diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..c905727
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,8 @@
+# 开发约定
+
+- 框架保持通用，不内置接入项目的业务类型、字段、错误码或业务规则。
+- 2026-09-25 用户要求：每次功能开发完成，必须同步维护根 README.md。README 需要覆盖当前全部公开功能，解释用途、基本用法，并提供可运行示例或链接到 examples 内的完整示例。
+- 新增、调整和删除功能都必须同步文档、示例、测试与发布说明。删除功能要明确说明已移除内容、影响范围和迁移步骤，不能继续把历史用法当作当前能力推荐。
+- examples 使用通用场景，避免依赖业务项目、私有数据库或线上服务。必要的外部基础设施配置应明确说明。
+- 2026-09-25 用户决定：移除 mappings/mappingFiles 及结构映射代码生成机制，改用可选 copyx 工具包。不得恢复另一套 JSON 或 Go 映射声明语言。
+- 深拷贝的自定义转换结果不得与输入共享可变引用；发现共享应报错，不能降级成浅拷贝或静默接受。
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6ef56c4..b928528 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,14 @@
 # Changelog
 
+## v0.19.0-preview（2026-09-25）
+
+- 新增通用可选 copyx：构造器、浅/深拷贝、精确类型转换、字段规则、nil/零值策略、并发复用。
+- 深拷贝拒绝自定义结果共享源可变引用；原子提交目标、保留错误链、限制遍历及估算分配。
+- 移除 JSON 结构映射配置与生成；提供明确迁移诊断，保留公共字段组合等其他生成能力。
+- 同步 README 全部能力索引、COPY.md、可运行示例和开发文档约定。
+- 验收与不兼容迁移见 [发布说明](RELEASE.md)、[copyx 验收](reports/copyxAcceptance.md)。v0.14–v0.18 的完整变更保留在发布说明历史段落。
+
+
 ## v0.13.0-preview（2026-09-24）
 
 - 新增通用 lifecycle.Controller，svc.RequestShutdown 支持依赖主动通知正常停止或致命故障，通知不阻塞，首个故障原因保留；生成入口排空 HTTP 后关闭依赖与日志，故障退出码为 1。
diff --git a/COPY.md b/COPY.md
new file mode 100644
index 0000000..43e0c75
--- /dev/null
+++ b/COPY.md
@@ -0,0 +1,141 @@
+# 可选拷贝工具 copyx
+
+v0.19 用普通 Go 调用取代 JSON 结构映射生成。`copyx` 只依赖标准库，不需要注册到 App，不执行 JSON 往返，也不会自动暴露数据库模型。普通 Logic 直接使用 `.api` 生成的 DTO；只有存在独立业务类型或需要隔离可变数据时才用它。
+
+完整可运行代码：[examples/copying](examples/copying)。在框架根目录运行：
+
+```sh
+go run ./examples/copying
+go test -race ./copyx ./examples/copying
+```
+
+## 最简单的调用
+
+```go
+import "git.yuntuo.hk/k2safe/go-omni/copyx"
+
+type Request struct { Name string; Enabled bool }
+type Input struct { Name string; Enabled bool }
+
+req := Request{Name: "sample", Enabled: false}
+var input Input
+if err := copyx.Copy(&input, req); err != nil { return err }
+```
+
+同名、同类型字段直接赋值。默认不会跳过 `false`、`0`、空字符串。目标字段没有来源时报错；多余源字段默认忽略，使用 `WithStrictFields()` 可要求源字段也全部使用或显式忽略。
+
+默认是浅拷贝：同类型指针、map、slice 共享引用，符合普通 Go 赋值。JSON tag 不参与字段匹配。不会自动调用方法、SQL Scanner/Valuer，或把 `int32`、`int64`、string、命名标量互相强转。
+
+新字段：普通接口只改 `.api` 和使用该字段的 Logic。独立 DTO/业务类型都需要此字段时，两边各声明一次；同名同类型不增加拷贝配置。检查在运行时发生，实际类型对必须有测试，不能把运行时工具当作旧生成器的编译期字段覆盖检查。
+
+## 深拷贝与构造器
+
+```go
+snapshot, err := copyx.Clone(source) // 保持源的静态类型，始终深拷贝
+if err != nil { return err }
+
+copier, err := copyx.New(copyx.WithDeepCopy(), copyx.WithStrictFields())
+if err != nil { return err }
+var result Output
+if err := copier.Copy(&result, source); err != nil { return err }
+```
+
+`Copy` 的目标必须是非 nil 指针；`Clone[T]` 返回 `(T, error)`。重复执行时在初始化阶段创建 Copier 并复用；配置之后不可变，每次调用独立持有遍历状态，可以并发使用。源、目标的并发读写仍由调用方同步，自定义函数也须支持并发。
+
+深拷贝会分配指针、map、slice，递归处理结构、数组、接口中的具体值。nil 集合与非 nil 空集合保持区别；slice 结果容量为长度，不复制长度之外的隐藏元素。普通循环和重复指针可处理。循环图应保留根指针，使用 `Clone(sourcePointer)` 或 `Copy(&targetPointer, sourcePointer)`；将循环指针根压成值结构会明确报错。
+
+它保证结果不引用输入中的可变对象，不保证保留所有底层内存布局关系：不同重叠 slice 视图会分别复制，内部指针指向某个切片元素的关系也不重建。字符串和零尺寸值可安全共享；`time.Time` 按 Go 不可变值使用（Location 不做独立复制）。不要通过 unsafe 或 uintptr 隐藏可变引用后要求工具识别。
+
+## 字段差异与自定义转换
+
+```go
+type Input struct { Name string; UpdatedAt time.Time; InternalID string }
+type View struct { DisplayName string; UpdatedAt string; LocalNote string }
+
+copier, err := copyx.New(
+    copyx.WithDeepCopy(),
+    copyx.WithStrictFields(),
+    copyx.WithFieldNames[Input, View](map[string]string{"Name": "DisplayName"}),
+    copyx.WithIgnoreSource[Input, View]("InternalID"),
+    copyx.WithIgnoreTarget[Input, View]("LocalNote"),
+    copyx.WithConverter(func(v time.Time) (string, error) {
+        return v.UTC().Format(time.RFC3339), nil
+    }),
+)
+if err != nil { return err }
+out := View{LocalNote: "preserve"}
+if err := copier.Copy(&out, input); err != nil { return err }
+```
+
+字段规则的类型参数必须是结构类型，字段名使用导出的 Go 字段名。构造时检查不存在的字段、重名及冲突。不支持字符串路径表达式；复杂嵌套差异为该嵌套类型注册 converter，或直接写 Go。
+
+`WithIgnoreSource` 只是声明该源字段不参与使用；目标同名字段若仍需保留，还需 `WithIgnoreTarget`。忽略目标会保留原目标值，Clone 中则为零值。深拷贝时如果保留值仍与源共享可变引用，也会拒绝。
+
+转换器的签名是 `func(S) (T, error)`，按**精确类型对**匹配，不能重复注册。金额、编号、日期格式由项目明确转换。需要逐字段不同规则时，给整个源/目标结构注册函数；函数返回独立的新目标。无需另一份映射配置或全局注册。
+
+精确 converter 优先于 nil/零值策略，能收到 typed nil；例如 `func(*Money) (Money, error)` 可自行决定 nil 是否允许。绑定到 `any` 字段的 converter 能接收 nil interface，但顶层未带类型的 `nil` 没有精确类型可匹配。浅拷贝中已经直接共享的同类型容器不会继续逐项转换其内部；需要遍历内部时选择深拷贝，或为该容器类型注册 converter。
+
+## 深拷贝不能原样返回可变引用
+
+```go
+copier, err := copyx.New(
+    copyx.WithDeepCopy(),
+    copyx.WithConverter(func(v []string) ([]string, error) {
+        return v, nil // 会返回 ErrSharedReference
+    }),
+)
+```
+
+检查覆盖完整源图与转换结果，包括新父对象引用旧子对象、原 map、重叠子切片、`source[:0]` 的可写容量、指向源数组元素的指针，以及未导出字段中的引用。会检查每个 converter 的结果和最终目标，不允许静默降级为浅拷贝。
+
+返回相同字符串、整数并不会报错，它们不是可变引用。正确切片 converter 可以写：
+
+```go
+copyx.WithConverter(func(v []string) ([]string, error) {
+    if v == nil { return nil, nil }
+    out := make([]string, len(v))
+    copy(out, v)
+    return out, nil
+})
+```
+
+第三方 Decimal/自定义 Money 如果含未导出的指针，默认深拷贝拒绝；注册该类型的 converter，使用它自己的构造/Clone API 创建独立值，避免转成 float64 损失精度。框架不内置某一金额库的规则。无法独立复制的类型直接返回错误。
+
+## nil、零值和错误
+
+| 选项 | 行为 |
+| --- | --- |
+| 默认 `NilError` | nil → 可空目标保留 nil；nil → 非可空目标报 `ErrNil` |
+| `WithNilPolicy(NilZero)` | 显式允许 nil → 零值；可空目标仍为 nil |
+| `WithNilPolicy(NilSkip)` | nil 保留已有目标；新集合元素没有旧目标，保留元素零值 |
+| `WithSkipZero()` | 显式跳过 Go 零值，包括 `false`、`0`、`""`；非 nil 空集合不是 Go 零值 |
+
+所有 nil 策略都不把不兼容类型自动变成兼容类型。非 nil 指针与值之间可以按对应元素转换；nil 到非可空目标仍需选择策略。局部更新不能默认使用 NilZero/SkipZero，它们可能改变清空字段或布尔值的业务语义。
+
+工具只能复制绑定后的 Go 值：如果输入类型已经将“缺失”和“JSON null”合并为 nil，无法恢复两者区别。需要三态时，应先设计包含 presence 信息的类型和绑定逻辑。
+
+赋值使用临时结果，成功后才替换目标；转换失败不会交付部分结果。`*copyx.Error` 包含 Go 字段/索引路径，`errors.Is/As` 保留内部错误链，工具不主动在错误中加入源值。converter 自己返回的错误文本仍由项目负责。
+
+converter 必须只读输入；其外部副作用、输入修改无法回滚，panic 原样传播。框架只检查与本次输入的共享引用，无法证明 converter 未返回外部全局缓存的引用。它是受信 Go 代码扩展，不是可运行不可信代码的沙箱。
+
+## 支持范围与资源限制
+
+- 支持结构体、指针、interface、slice、同长度 array、map。map key 转换后冲突或不可比较则报错。
+- 导出匿名结构字段可按提升后的无歧义名称访问；源嵌入指针为 nil 且需要其字段时明确报错。跨类型目标包含私有字段时拒绝；同类型私有纯值可作为整体保留。
+- 不克隆文件、数据库连接、网络连接、锁、原子状态。已知标准库资源/同步结构按值复制也拒绝；深拷贝中的非 nil func、chan、unsafe.Pointer 拒绝。其他封装资源类型应由项目排除，工具不能识别所有自定义句柄。
+- 单次遍历深度上限 256、节点上限 200,000；内置分配的估算预算为 64 MiB，超限返回 `ErrLimit`。预算不是进程堆内存硬限制，reflect 元数据和 converter 自行分配不计入。大对象流式读写应使用 IO/存储接口。
+- 只缓存不可变类型元数据，不缓存请求值、用户 converter 或实例策略。没有 `unsafe` 写入、JSON 往返、隐式数值截断或方法调用。
+- 这是运行时反射工具，会比直接 Go 赋值多检查与分配。热点应复用 Copier，并用真实数据测量；性能记录见 [本版验收](reports/copyxAcceptance.md)。
+
+## 从旧 mapping 迁移
+
+v0.19 **彻底移除**映射配置加载、Go 类型加载、映射代码生成及 `pointerResult` 等附属选项。公共 `.api` 字段组合、scalar、中间件工厂、Repository 开关继续存在。
+
+1. 先检查每个转换是否必要。普通 Logic 可直接使用生成 DTO；独立核心保留自己的类型。
+2. 将 `mapping.Xxx(...)` 调用改为普通 Go 或小型 `copyx` helper。字段改名、nil、金额规则写在该 helper 同一处。指针返回可直接 `var out *Response; err := copier.Copy(&out, input)`。
+3. 用真实类型对测试缺失/null/零值/空数组、字段覆盖、金额精度和错误链。需要源字段新增时提醒遗漏，启用 `WithStrictFields()` 并测试。
+4. 从 `omni.gen.json` 删除 `mappings` / `mappingFiles`，删除无其他用途的映射 JSON 文件。
+5. 确认已无调用，再删除 `internal/mapping/mappingsGen.go`。如之前手改过文件，先迁出手写内容。生成器遇到该旧文件会阻止生成并提示迁移，**不会静默删除**；其余业务文件照常保留。
+6. 升级框架与 CLI 到同版，执行 generate、generate --check、go test ./...；多个服务再执行 workspace generate/check。新 manifest 自动去掉已移除文件的所有权记录。
+
+历史发布记录保留旧能力说明，仅用于理解旧版本，不代表 v0.19 继续支持。
diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 594d3da..f4419e4 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -1,8 +1,8 @@
-# 通用业务开发指南（v0.18.0-preview）
+# 通用业务开发指南（v0.19.0-preview）
 
 从 [README](README.md) 创建服务后，业务主要维护 `.api`、配置、`svc.Init`、Logic、Repository 和项目中间件。本页说明通用接入能力；字段、错误码、权限、表结构和事务边界都由项目定义。
 
-本版新增的公共字段组合、可选结构映射、自动中间件工厂和 Repository 开关，见 [生成能力指南](GENERATION.md)。
+公共字段组合、自动中间件工厂和 Repository 开关，见 [生成能力指南](GENERATION.md)。必要的结构转换使用可选 [copyx](COPY.md)，v0.19 已移除旧 JSON 映射生成。
 
 ## 返回数组、可空对象和 null
 
@@ -278,7 +278,7 @@ go-omni workspace check --file omni.workspace.json
 
 ## v0.13 项目升级
 
-先使用与目标框架匹配的 CLI；CLI 会提示与 go.mod 不同的版本。当前生成模板至少需要 v0.18.0-preview（或显式引用当前源码）。
+先使用与目标框架匹配的 CLI；CLI 会提示与 go.mod 不同的版本。当前生成模板至少需要 v0.19.0-preview（或显式引用当前源码）。
 
 ```sh
 go-omni api upgrade --dir . --dry-run
diff --git a/GENERATION.md b/GENERATION.md
index 02b59c2..65d1366 100644
--- a/GENERATION.md
+++ b/GENERATION.md
@@ -1,18 +1,10 @@
-# 公共字段、结构映射与生成选项
+# 公共字段、中间件工厂与生成选项
 
-本页对应 `v0.18.0-preview`。CLI 与框架依赖固定到同一版本：
-
-```sh
-go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.18.0-preview
-# 已有业务项目内执行：
-go get git.yuntuo.hk/k2safe/go-omni@v0.18.0-preview
-```
-
-私有仓库访问设置见 [安装说明](README.md#准备环境与安装)。升级不会覆盖业务文件；已有中间件保持 handlers 模式，切换工厂模式按本页迁移步骤完成。
+本页对应 `v0.19.0-preview`。CLI 与框架依赖固定到同一版本，安装见 [README](README.md#准备环境与安装)。
 
 ## 一份项目生成配置
 
-新项目根目录生成开发者维护的 `omni.gen.json`：
+新项目根目录的 `omni.gen.json` 只描述生成选项：
 
 ```json
 {
@@ -21,32 +13,11 @@ go get git.yuntuo.hk/k2safe/go-omni@v0.18.0-preview
 }
 ```
 
-该文件与 `.api` 一起提交。每次 `api generate`、`--check`、`--dry-run` 和 `workspace generate/check` 都会读取；`api validate/export/format` 只处理契约，不加载业务 Go 类型。
-
-- `repository: none` 是默认值，不创建空 Repository 文件。`group` 按 `.api` 的 group 补齐 `internal/repository/<group>/repository.go`；文件始终属于业务。切回 none 后不再补骨架，已有文件不删除、不覆盖。实际 SQL、ORM 和仓储划分由项目决定。
-- `middleware: factories` 是新项目默认值，按下文自动初始化。`handlers` 保留原有 `Defaults()` 与 `func(next Handler) Handler` 接口，供既有项目逐步迁移。
-- `mappings` 可省略；只有明确列出的类型对才生成映射。未启用时不会运行 Go 类型加载命令，也不增加运行时依赖。
-- 升级首次遇到没有配置的旧 manifest 时，补一份 `middleware: handlers` 的配置，保留原有手写注册；Repository 默认 none。生成配置建立后不能直接删除，否则生成失败，避免误关闭映射或改变中间件模式。
-
-### 按模块拆分映射（v0.18 新增）
-
-主配置可以保留少量内联 `mappings`，也可以只列出文件：
-
-```json
-{
-  "repository": "none",
-  "middleware": "factories",
-  "mappingFiles": ["mappings/requests.json", "mappings/responses.json"]
-}
-```
-
-每个子文件只包含 `{"mappings": [...]}`，其中每条映射的写法与原来一致。先加载主配置内联定义，再按文件列表顺序加载；所有定义合并后统一校验，可以跨文件、向前引用 `mapping`。输出按映射名排序，文件拆分不改变函数名或语义。
-
-- 路径相对项目根目录，必须是明确列出的 `.json` 文件。不展开通配符，不允许越界路径、符号链接、重复文件或多层导入；子文件不能覆盖 repository/middleware 等项目选项。
-- 重名映射、指针辅助函数名冲突、未知映射与循环引用明确报错；文件之间不能用覆盖顺序隐藏冲突。重复定义会指出两个来源文件，字段生成错误也带来源文件。
-- 文件均由项目维护，重新生成不改写它们。原来的单文件 `mappings` 继续有效。迁移时将完整条目移到子文件并删除原位置，不能复制后保留两份同名定义。
-- 最多 64 个子文件、单文件 1 MiB、全部配置 4 MiB；合计仍最多 128 个映射。主配置和子文件一起提交 Git。
-- `api generate`、`--check`、`--dry-run` 与 `workspace generate/check` 使用同一加载逻辑。缺少子文件或不完整配置立即失败，check/预览不写入；生成期间重新核对所有配置输入，发生变化时要求重试。
+- `repository: none` 默认不创建空 Repository 文件；`group` 按 group 补齐可编辑骨架。已有文件始终保留；切回 none 不会删除业务文件。SQL、ORM 和仓储划分由项目决定。
+- `middleware: factories` 是新项目默认值，自动调用带依赖的工厂。`handlers` 保留原有 `Defaults()` 及手动注册方式，供既有项目迁移。
+- 该文件与 `.api` 一起提交。generate/check/dry-run 和 workspace 采用相同规则；validate/export/format 只处理接口契约。
+- 旧 manifest 没有配置时补 `middleware: handlers`、`repository: none`。已有配置不能直接删除，避免意外切换中间件模式。
+- v0.19 已删除 `mappings` 和 `mappingFiles`；遇到旧配置会明确报错，不读取子映射文件或执行映射生成。处理步骤见 [copyx 迁移](COPY.md#从旧-mapping-迁移)。
 
 ## 公共字段组合
 
@@ -73,151 +44,13 @@ type AdminRequest {
 
 允许多层组合，上限 32 层、单类型 4096 字段、全契约展开 65536 字段。Go 匿名指针嵌入并非本功能；生成 DTO 中不会使用匿名嵌入。
 
-## 可选结构映射
+## DTO 与业务类型
 
-`.api` 生成 DTO，业务独立维护输入/结果类型。项目明确选择需要自动赋值的类型对；不从数据库反向生成公开接口，不自动推断反向映射。
+普通 Logic 直接接收生成的 Request、返回生成的 Response，不额外创建相同结构。只有独立核心或明确不同的输入/输出职责才保留业务类型。
 
-假设 `types.AdminRequest` 有 `Name string`、`Salary amount.Money`、`CompanyID string`，业务的 `domain.EmployeeInput` 有 `EmployeeName string` 和同类型 `Salary`：
+必要转换直接写 Go，或用可选 `copyx.Copy(&target, source)`。同名同类型字段自动赋值，字段改名和类型变化通过 Go 参数、转换函数明确设置，见 [完整示例](examples/copying/main.go)。无需 JSON 映射配置、包路径字符串或额外生成文件。
 
-```json
-{
-  "repository": "none",
-  "middleware": "factories",
-  "mappings": [
-    {
-      "name": "ToEmployeeInput",
-      "source": {"package": "example.com/payroll/internal/types", "type": "AdminRequest"},
-      "target": {"package": "example.com/payroll/internal/domain", "type": "EmployeeInput"},
-      "fields": {
-        "EmployeeName": {"source": "Name"}
-      },
-      "ignoreSource": {
-        "CompanyID": "由 Logic 单独做企业范围授权，不属于请求体输入"
-      }
-    }
-  ]
-}
-```
-
-执行 `go-omni api generate` 后，产生独立的生成文件 `internal/mapping/mappingsGen.go`：
-
-```go
-func ToEmployeeInput(source types.AdminRequest) (domain.EmployeeInput, error) {
-    var result domain.EmployeeInput
-    result.EmployeeName = source.Name
-    result.Salary = source.Salary
-    return result, nil
-}
-```
-
-包别名由生成器决定。业务调用 `mapping.ToEmployeeInput(*req)`；反向响应映射按另一条 source/target 规则声明。两个类型完全相同时通常无需映射。
-
-### 类型与覆盖检查
-
-自动赋值要求同名且 **Go 类型一致**（类型别名按 Go 类型系统处理），字段名使用 Go 名称，不按 JSON 标签猜对应关系。int32 → int64、`*Money` → Money、数值 ID → string 都必须显式转换。不会暗中补零、解引用或执行数字强转。
-
-每个源字段必须被使用或出现在 `ignoreSource`；每个目标字段必须被赋值或出现在 `ignoreTarget`。忽略规则必须给出非空原因，目标忽略明确意味着保留零值；规则引用不存在的字段也会失败。新字段若无法自动匹配，会在生成阶段报错。两边同时添加的同名同类型字段会自动加入生成代码，`--check` 检出未重新生成的差异。
-
-根类型是项目可导入的具名结构；支持值类型匿名嵌入，规则可用 `Employee.EmployeeName` 这样的实际 Go 字段路径。同名提升歧义、未导出字段和匿名指针嵌入拒绝处理。普通具名嵌套字段使用独立映射或转换函数，不猜测内部结构。泛型声明不能直接作为根；具体字段类型按 Go 类型系统检查。
-
-配置变化、遗漏映射、类型错误会在写入前失败。映射生成与其他生成产物使用同一套文件所有权机制；手改映射生成文件会被拒绝覆盖。
-
-### 显式转换函数
-
-```json
-"fields": {
-  "Salary": {
-    "source": "Salary",
-    "convert": {"package": "example.com/payroll/internal/convert", "name": "SalaryValue"}
-  }
-}
-```
-
-支持这两种精确签名：
-
-```go
-func SalaryValue(source *amount.Money) amount.Money
-func SalaryValue(source *amount.Money) (amount.Money, error)
-```
-
-项目选择一种实现。nil、默认值、金额精度、日期格式和错误码由函数负责；若两边已经是同一个 Money 类型，无需再次解析或序列化。转换函数应仅负责值转换，不执行 SQL 或改变授权范围。
-
-错误通过 `%w` 加上映射名/目标字段路径，保留 `errors.Is/As` 和框架错误链；返回零目标值，不交付部分完成的结果。包装不主动添加源值或转换后的值。错误是否公开仍由项目错误目录和响应策略决定。
-
-### 嵌套对象、数组与引用
-
-`mapping` 指向同配置中的另一条映射，`elements` 明确要求逐项映射：
-
-```json
-"fields": {
-  "Summary": {"source": "Summary", "mapping": "ToSummary"},
-  "Items": {"source": "Items", "mapping": "ToItem", "elements": true}
-}
-```
-
-`mapping` 与 `convert` 互斥。`elements` 可以配合其中任意一种，也可以对类型相同的元素直接赋值；支持 slice→slice、等长 array→array，禁止隐式互转。nil slice 保持 nil，非 nil 空 slice 保持非 nil，逐项失败的错误包含索引，循环映射声明被拒绝。
-
-未选择 elements 的同类型指针、map、slice 使用普通 Go 赋值，**共享引用**，不做隐式深拷贝。elements 会分配新的目标 slice，但元素内的引用仍遵循其映射规则。需要深拷贝时显式提供转换函数。
-
-映射不保存原 JSON 的字段存在信息。普通 `*T` 在绑定后可能已把缺失和 null 合并为 nil；无法在转换阶段恢复区分。有三态需要的项目必须先使用能携带该信息的输入类型及绑定扩展；没有声明三态时，保持当前输入类型的语义。完整表单更新和局部更新由业务决定，框架不把 nil 自动解释成“保留旧值”。
-
-### 可空嵌套映射与显式 nil 策略（v0.18 新增）
-
-假设已有 `ToChild` 定义 `types.Child → domain.Child`。父对象的字段规则可以直接复用它：
-
-```json
-"fields": {
-  "Child": {"source": "Child", "mapping": "ToChild"},
-  "Children": {"source": "Children", "mapping": "ToChild", "elements": true}
-}
-```
-
-| 源字段 → 目标字段 | 明确选择 mapping 后的行为 |
-| --- | --- |
-| `S → T` | 调用原值映射 |
-| `*S → *T` | 默认保留 nil；非 nil 调用值映射，并分配新的目标对象；也可配置 `nil: "error"` 拒绝 nil |
-| `S → *T` | 调用值映射，成功后返回目标对象指针 |
-| `*S → T` | 必须选择 `nil: "zero"` 或 `nil: "error"`，不猜默认值 |
-
-`nil: "preserve"` 只适用于可空源和可空目标。`nil: "zero"` 只适用于可空源和非空目标：nil 直接产生目标 Go 零值，**不调用子映射或转换函数**。`nil: "error"` 在 nil 时返回带映射/字段路径的普通转换错误，HTTP 公开响应仍由项目的错误处理策略决定；需要领域错误码时使用项目 converter。
-
-同一规则适用于显式 `elements: true` 下的 slice/等长数组元素，包括 `[]*S → []*T`。nil slice、非 nil 空 slice、nil 元素分别保留；元素失败保留索引与内部错误链，整个映射返回零目标值，不交付部分结果。只支持这里列出的单层指针，不自动处理多层指针或递归对象图。
-
-普通同类型指针字段未指定 mapping 时仍直接赋值、共享引用；上述显式映射会创建目标子对象，但不承诺对其中所有引用深拷贝。业务不可变快照继续由项目设计。
-
-简单的 `*T → T` 也可以单独指定 nil 策略，减少重复解引用函数：
-
-```json
-"fields": {
-  "Title": {"source": "Title", "nil": "zero"},
-  "Count": {"source": "Count", "nil": "error"}
-}
-```
-
-这里必须是完全相同的 Go 元素类型，`*int32 → int64`、枚举 → string、数字编号 → string 仍需显式 converter。非 nil 的零值正常保留。`convert` 与 `nil` 不能同时设置，现有 converter 继续完整控制自己的空值、格式和错误语义。
-
-### 可选指针返回辅助（v0.18 新增）
-
-在映射条目上增加 `"pointerResult": true`，生成器保留 `ToResponse(source S) (T, error)`，另加：
-
-```go
-func ToResponsePtr(source S) (*T, error)
-```
-
-Logic 在业务调用成功后可直接写 `return mapping.ToResponsePtr(result)`。转换失败时返回 `nil, err`，错误链不变；成功才返回非 nil 指针。业务调用本身的错误仍由 Logic 处理，辅助函数不执行任何业务操作。
-
-辅助函数名称固定为映射名加 `Ptr`，与其他映射/辅助函数同名会在生成前报错。输入仍是原来的值类型 S，不用 nil 输入表达业务错误；关闭该选项会移除辅助函数，使用它的业务代码需同时调整。
-
-### 生成顺序与 CI
-
-1. 先从 `.api` 生成项目，添加业务结构、scalar 和转换函数，执行 `go mod tidy`。
-2. 在 `omni.gen.json` 列出映射，执行 `go-omni api generate`。
-3. Logic 调用生成函数。后续改字段后重复生成，不修改 `*Gen.go`。
-4. CI 同时运行 `go-omni api generate --check` 与 `go test ./...`。
-
-启用映射后，CLI 通过 `go list -deps -export` 加载明确声明的包与依赖，按当前构建环境做类型检查，不执行业务代码、init 或转换函数。采用待生成 DTO 的临时 overlay，避免“新增字段还看旧 DTO”。go.mod/go.sum 的副本及 overlay 都在临时目录，check 不修改项目文件；Go 自己的构建/模块缓存可能更新。使用当前 GOOS/GOARCH/GOFLAGS、`GOWORK=off`；依赖用 go.mod 与 replace 表达，生成超时为 90 秒。
-
-类型包/转换函数包不能依赖输出包 `internal/mapping`；把转换函数放在独立包中，避免导入环。若包本身无法编译，先运行 `go list -deps -export <相关包>` 排查；CLI 不回显可能含私有仓库凭据的 Go 下载输出。纯值字段转换只生成标准 Go 代码，不引入运行时反射搬运、JSON 往返、ORM 或队列依赖。
+`copyx` 在运行时检查类型和字段，**不提供旧映射生成阶段的静态字段覆盖保证**；CI 应给实际类型对添加测试。普通业务字段新增通常只改 `.api` 和 Logic；独立 DTO/领域类型都需要此字段时，两边各加一次，同名同类型无需追加拷贝配置。
 
 ## 中间件工厂自动注册
 
@@ -271,9 +104,13 @@ factory 模式不再在 Init 写 `Middlewares["..."]`；残留非空手写注册
 | 项目维护 | 生成器持续维护 |
 | --- | --- |
 | `.api` 公共字段与接口 | 展开后的 DTO、Handler、OpenAPI |
-| `omni.gen.json` 的映射与选项 | `internal/mapping/mappingsGen.go` |
-| Go 业务类型、scalar、转换函数 | 编译期可检查的赋值与调用代码 |
+| `omni.gen.json` 的 Repository/中间件选项 | 对应骨架和注册代码；已有手写骨架不覆盖 |
+| 独立 Go 业务类型、scalar、可选 copyx 调用和测试 | 不生成结构转换文件 |
 | middleware Dependencies、具名工厂、svc 访问器 | 中间件 registry、启动调用 |
-| Logic、按需 Repository、配置、svc 初始化/清理登记 | main、runtime、路由接入 |
+| Logic、Repository、配置、svc 初始化/清理登记 | main、runtime、路由接入 |
 
-回归样例位于 `cmd/go-omni/apigen/testdata/composition`，为独立三端服务，不导入任何 eTax 代码。
+独立三端工资契约测试位于 `cmd/go-omni/apigen/testdata/composition`，不导入任何接入项目。它验证公共字段、Money scalar、三端 Handler、copyx、重新生成保留业务内容，以及新增字段不需要更新转换规则。
+
+```sh
+GO_OMNI_SCAFFOLD_INTEGRATION=1 go test ./cmd/go-omni/apigen -run TestCopyxThreeEndpointConsumer -count=1
+```
diff --git a/PROJECT.md b/PROJECT.md
index f58bd4a..b8958b8 100644
--- a/PROJECT.md
+++ b/PROJECT.md
@@ -1,6 +1,6 @@
 # 生成项目与文件维护边界
 
-v0.18.0-preview 提供受管理的生成项目。安装同版远程 CLI，生成的项目直接引用该版本，无需本地 replace。根目录入口支持 `go run .` 和 `go build .`；框架本身仍然是可直接引用的库。安装和私有仓库访问见 [README](README.md#准备环境与安装)。
+v0.19.0-preview 提供受管理的生成项目。安装同版远程 CLI，生成的项目直接引用该版本，无需本地 replace。根目录入口支持 `go run .` 和 `go build .`；框架本身仍然是可直接引用的库。安装和私有仓库访问见 [README](README.md#准备环境与安装)。
 
 ## 创建和日常开发
 
@@ -54,14 +54,15 @@ ERROR [logicSignature] internal/logic/greet/greet.go:12 (GET /api/greet/:name):
 | `internal/logic/<group>/*.go` | 业务方法，使用标准 context.Context |
 | `internal/repository/<group>/*.go` | 数据访问；默认不补空骨架，可选 group 模式 |
 | `internal/middleware/*Factory.go`、`dependencies.go` | 中间件工厂与依赖小接口，svc 实现访问器 |
-| `omni.gen.json`、映射转换函数（支持 `mappingFiles` 引用子文件） | 生成选项、显式类型对与差异规则 |
+| `omni.gen.json` | Repository 和中间件生成选项；不再声明结构映射 |
+| 可选的 Go 转换函数 / copyx 调用 | 只有独立类型确实需要转换时维护，见 [copyx](COPY.md) |
 | 项目 Go 错误包 | 自行维护 Catalog 和常量，可跨服务共用 |
 | 自定义标量文件、`*Bind.go`、`*Manual.go` | 只有显式选择相应扩展时才生成/使用 |
 | 项目测试、迁移、部署脚本、go.mod/go.sum | 项目所有，生成器不重置其内容 |
 
 以上骨架只补缺失文件，既有内容按字节保留。删除已废弃接口后，对应业务文件也不会被自动删除；由开发者整理编译器指出的失效类型或签名。
 
-生成器持续管理：`internal/svc/runtimeGen.go`、`main.go`、`internal/handler/*Gen.go`、分组的 `handlersGen.go`、`internal/types/*Gen.go`、可选映射 `internal/mapping/mappingsGen.go`、中间件 `registryGen.go`、`docs/openapi.json`、`.goOmni/apiManifest.json`。如果在 `.api` 里选择声明错误，还会管理 `internal/apierrors/errorsGen.go`。文件标注 DO NOT EDIT；手改会被拒绝覆盖，需先移走自定义内容。
+生成器持续管理：`internal/svc/runtimeGen.go`、`main.go`、`internal/handler/*Gen.go`、分组的 `handlersGen.go`、`internal/types/*Gen.go`、中间件 `registryGen.go`、`docs/openapi.json`、`.goOmni/apiManifest.json`。如果在 `.api` 里选择声明错误，还会管理 `internal/apierrors/errorsGen.go`。文件标注 DO NOT EDIT；手改会被拒绝覆盖，需先移走自定义内容。
 
 Logic 实例在注册时创建并由请求并发复用；请求数据用方法参数和局部变量传递，不存入共享 Logic/svc 字段。
 
@@ -211,7 +212,7 @@ get /download (DownloadReq)
 
 ## 已有服务接入步骤
 
-每个独立服务生成一个项目，module 名称、上层目录和共享业务包由项目选择。接入时固定 CLI 与框架版本为 v0.18.0-preview：
+每个独立服务生成一个项目，module 名称、上层目录和共享业务包由项目选择。接入时固定 CLI 与框架版本为 v0.19.0-preview：
 
 1. 先保留旧服务，整理实际路由及现有响应、鉴权和超时要求。在新目录执行 `go-omni new --api /path/to/service.api --module example.com/service ./service`；不对旧入口强制覆盖。
 2. 在 `.api` 中选择 `@app(defaultResponse: ...)`，显式保留原项目的字段、成功码、错误码和 `dataMode`。需要独立回执的路由单独声明 raw/produces。普通路由、404/405 和提前返回的中间件一起验收。
diff --git a/README.md b/README.md
index 1d23b48..9a91868 100644
--- a/README.md
+++ b/README.md
@@ -2,17 +2,17 @@
 
 GoOmni 是面向多个业务项目复用的 Go 后端框架：用 `.api` 定义接口、请求和返回类型，生成项目目录、HTTP 接入代码及 OpenAPI，业务代码负责 Logic 和 Repository。也可以在已有项目中直接使用 `omni.New()`，或单独引入日志、存储等模块。
 
-**从这份 README 开始接入。** 当前版本 **`v0.18.0-preview`**，新生成项目采用根目录入口和 `config / svc / logic / handler`。可以固定版本开展业务接入；文件维护边界和已有服务迁移步骤见 [项目指南](PROJECT.md)，版本变化与验收见 [发布说明](RELEASE.md)。
+**从这份 README 开始接入。** 当前版本 **`v0.19.0-preview`**，新生成项目采用根目录入口和 `config / svc / logic / handler`。可以固定版本开展业务接入；文件维护边界和已有服务迁移步骤见 [项目指南](PROJECT.md)，版本变化与验收见 [发布说明](RELEASE.md)。
 
-**v0.17 提供**：公共字段组合、可选结构映射、带依赖的中间件工厂、按需 Repository 骨架，使用与迁移见 [生成能力指南](GENERATION.md)。
+**v0.19 改动**：新增可选 `copyx` 工具，用普通 Go 调用完成浅拷贝、深拷贝和显式类型转换；深拷贝会拒绝自定义转换中残留的源对象可变引用。**移除了 `mappings` / `mappingFiles` 和映射代码生成**，已有使用者须按 [迁移步骤](COPY.md#从旧-mapping-迁移) 调整，不能直接删除仍在调用的旧文件。
 
-**本版新增**：可空嵌套映射、映射配置按文件拆分、显式 nil 策略和可选指针返回辅助，见 [生成能力指南](GENERATION.md)。
+普通接口的流程是：**修改 `.api` → 生成 Request/Response → 写 Logic → 测试**。有独立职责的业务类型才需要转换；可直接写 Go，也可以按需使用 [copyx](COPY.md)。公共字段组合、中间件工厂、Repository 开关继续支持，见 [生成能力指南](GENERATION.md)。
 
 Go **1.22+**。框架不依赖 Gin，默认使用标准库网络层，提供可切换的 native HTTP/1.1 和实验性 HTTP/2 适配器。
 
 响应字段、业务码、登录方式、权限规则和数据库表结构由接入项目决定。文中的 `code/msg/data`、`200/9999` 都是示例配置，可以替换。
 
-本版补齐 `returns([]string/[]int64/[]bool/[]any)`、OpenAPI 公共引用、workspace 一次导出共享 Go 错误目录，以及统一环境变量别名覆盖。详细配置与升级步骤见 [业务开发指南](DEVELOPMENT.md)。
+契约支持 `returns([]string/[]int64/[]bool/[]any)`、OpenAPI 公共引用、workspace 一次导出共享 Go 错误目录，以及统一环境变量别名覆盖。详细配置与升级步骤见 [业务开发指南](DEVELOPMENT.md)。
 
 已有通用开发能力见 [业务开发指南](DEVELOPMENT.md)：数组/null、严格请求策略、声明式上传、完整配置环境覆盖、资源生命周期、共享契约和升级工具。MySQL 直接使用 [官方适配器](database/mysql/README.md)。
 
@@ -20,6 +20,40 @@ Go **1.22+**。框架不依赖 Gin，默认使用标准库网络层，提供可
 
 使用 GORM 的项目可以选择 [gormx 适配器](database/gormx/README.md)，复用数据库初始化和连接池，并将 SQL 日志接入 logx。
 
+## 当前功能与使用入口
+
+下表是当前公开能力的索引。每项给出调用入口和完整说明；模块按需使用，`omni.New()` 不会自动初始化数据库、Redis、ORM、队列或云存储。示例中的 import 统一以 `git.yuntuo.hk/k2safe/go-omni/` 开头。
+
+| 功能与用途 | 怎么用 | 解释与示例 |
+| --- | --- | --- |
+| 项目、接口与文档生成 | `go-omni new`；改 `.api` 后 `api generate`；`--check` 检查漂移 | [下方快速开始](#新项目生成并运行)、[CLI](cmd/go-omni/README.md)、[完整生成项目](examples/managedService/README.md) |
+| 公共字段与跨服务共享契约 | `.api` 组合对象字段；`omni.imports.json` 声明共享根；workspace 批量生成 | [公共字段示例](GENERATION.md#公共字段组合)、[共享契约与 workspace](DEVELOPMENT.md) |
+| 中间件依赖工厂、可选 Repository | `omni.gen.json` 选择 factories / none；在 `New<Name>(deps)` 写一次实现 | [配置与完整工厂示例](GENERATION.md) |
+| 路由、分组、请求上下文 | `omni.New()`、`app.GET` / `Group` / `Use`；业务使用 `context.Context` | [基本服务](examples/basic/main.go)、[已有项目接入](#已有项目按模块接入) |
+| HTTP 网络与扩展适配 | 配置 transport 为 nethttp / native / http2；自定义 Router/Runner | [网络层配置与契约](transport/README.md)、[性能与限制](PERFORMANCE.md) |
+| HTTP 老接口桥接 | 通过官方 Handler/Middleware 适配器接入标准 `net/http`，跟踪实际响应状态 | [接入说明](MIGRATION.md)、[桥接/上传/自定义 ID 示例](examples/compatibility/main.go) |
+| 请求校验、动态 JSON、自定义标量 | `.api` 声明来源/校验/scalar；手写契约用 `contract.New[T]`；简单绑定可用 `validate.JSON/Query/URI` | [语法与例子](API.md)、[请求策略](DEVELOPMENT.md) |
+| 数组、null、原始请求、上传下载 | `.api` 声明数组/可空返回、body/multipart 与大小限制；必要时使用 Bind/Manual 扩展 | [契约示例](examples/contracts)、[含上传/回调/下载的项目](examples/managedService/README.md) |
+| 公共响应与特殊协议 | `.api` 定义 response 并 `@app(defaultResponse: ...)`；Go 用 `WithResponse` / Encoder | [响应配置](RESPONSE.md)、[响应模板契约](examples/contracts/responses.api) |
+| 错误目录与动态提示 | `WithErrors(catalog)` 注册一次；`ByCode(...).WithParams(...).WithCause(err)` | [错误目录](errors/README.md)、[模板参数示例](examples/contracts/errorParams.api) |
+| OpenAPI 与错误公共引用 | `.api` 自动生成；手写接口可使用 `openapi` 注册器；Go 错误目录显式导出 | [契约工具](DEVELOPMENT.md)、[注册示例](examples/platform/main.go) |
+| 结构化业务日志 | `logx.Info/Error`、`logx.From(ctx)`、`logx.New`；支持轮转、脱敏、慢请求和级别更新 | [下方日志示例](#日志)、[完整配置](logx/README.md) |
+| 文件配置与环境覆盖 | 默认值→JSON/YAML→环境；完整业务结构用 `config.LoadProject[T]` / 环境别名 | [配置详解与例子](DEVELOPMENT.md)、[动态级别](ADVANCED.md#配置与日志热更新) |
+| 生命周期与健康检查 | svc 登记 OnClose/OnStop/OnDrain，RequestShutdown 通知故障；健康路径/开关可配 | [生命周期用法](lifecycle/README.md)、[健康检查](health/README.md)、[生成项目扩展](PROJECT.md) |
+| 数据库、连接池与事务 | `database.Open` / `OpenConnector`；事务与检查由项目显式调用 | [通用数据库](database/README.md)、[MySQL TLS/Logger](database/mysql/README.md) |
+| 可选 GORM 与迁移 | gormx 复用已有连接池；`go-omni migrate` 预览，显式 apply | [GORM 示例](database/gormx/README.md)、[迁移用法](ADVANCED.md#迁移审计与分页) |
+| 认证与权限接口 | 注入 Authenticator / Policy；JWT 或 Session 只是可选实现 | [认证说明](auth/README.md)、[鉴权完整例子](examples/platform/README.md) |
+| 缓存 | `cache.NewMemory` 或 Redis 实现；业务面向 Store 的 Get/Set/Delete | [缓存配置/代码](MODULES.md)、[可运行模块服务](examples/modules/README.md) |
+| 出站 HTTP、熔断 | `httpc.New` 复用连接池与截止时间；`resilience.New` 隔离故障依赖 | [HTTP 用法](MODULES.md)、[熔断/观测](ADVANCED.md#熔断与观测) |
+| CORS、日志、恢复、限流、幂等、超时 | `app.Use(...)` 按需组合 middleware；跨副本选择 Redis 实现 | [模块说明与限制](MODULES.md)、[分布式实现](ADVANCED.md#分布式限流与幂等) |
+| 本地后台任务与调度 | `task.New`、Submit、Every；有界队列、排空关闭 | [task 示例与生命周期](MODULES.md#后台执行task) |
+| 持久队列 | 业务使用 Publisher / Consumer；Redis Streams 提供至少一次交付 | [队列初始化/消费示例](ADVANCED.md#可靠队列) |
+| 文件存储、直传、云端分片 | Store 的 Put/Get/Delete；Local、S3/R2、OSS 按配置装配；扩展接口提供分片续传 | [存储接口与完整例子](storage/README.md)、[本地存储服务](examples/platform/README.md) |
+| 日志关联、指标与链路 | `metrics.New().Middleware()`；telemetry 注入 OTel exporter/reader | [观测用法](ADVANCED.md#熔断与观测)、[完整接入](examples/platform/main.go) |
+| 审计与分页 | `audit.New` 注入 Sink/白名单；`pagination.Parse` / `NewResult` | [解释与调用例子](ADVANCED.md#迁移审计与分页) |
+| 可选结构转换与深拷贝 | `copyx.Copy` / `Clone` / `New`；Go converter 处理差异 | [下方示例](#可选结构转换与深拷贝)、[完整 copyx 指南](COPY.md)、[可运行代码](examples/copying) |
+| 自定义适配器验收 | `transporttest.Run`、`storagetest.Run` / `RunUploads` 验证扩展契约 | [网络契约测试入口](transport/transporttest/router.go)、[存储契约测试入口](storage/storagetest/contract.go) |
+
 ## 选择接入方式
 
 | 你的项目 | 从哪里开始 |
@@ -40,7 +74,7 @@ module 地址是 `git.yuntuo.hk/k2safe/go-omni`。先确保本机 Go 和 Git 可
 
 ```sh
 export GOPRIVATE="$(go env GOPRIVATE),git.yuntuo.hk"
-go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.18.0-preview
+go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.19.0-preview
 export PATH="$(go env GOPATH)/bin:$PATH"
 go-omni --help
 ```
@@ -197,7 +231,7 @@ go-omni new --api catalog.api \
 在业务项目的 **go.mod 所在目录**执行：
 
 ```sh
-go get git.yuntuo.hk/k2safe/go-omni@v0.18.0-preview
+go get git.yuntuo.hk/k2safe/go-omni@v0.19.0-preview
 ```
 
 已有项目可直接复用现有目录、Service、Repository 和数据库连接，先选择一个接口接入。也可以只用 `logx`、`storage` 等包，暂时保留原来的 HTTP 框架。希望入口和 HTTP 接入都交给生成器的项目，按 [已有服务接入步骤](PROJECT.md#已有服务接入步骤) 在新目录生成后迁入业务代码。
@@ -391,6 +425,38 @@ return apierrors.TextTooLong("企业名称", 100)
 
 更详细的配置、作用域和升级步骤见 [统一错误目录](errors/README.md)。
 
+### 可选结构转换与深拷贝
+
+普通接口不需要任何拷贝配置，直接使用生成的 Request/Response。独立业务结构之间有转换需求时：
+
+```go
+// import "git.yuntuo.hk/k2safe/go-omni/copyx"
+var input DomainInput
+if err := copyx.Copy(&input, req); err != nil { return err }
+
+// 源与目标之间的指针、map、slice 需要隔离时：
+snapshot, err := copyx.Clone(source)
+if err != nil { return err }
+```
+
+默认浅拷贝，同名同类型字段自动赋值，保留零值；默认不会把 nil 填成非可空目标的零值。不要为使用工具新增一套重复模型。
+
+需要重复使用或自定义规则时创建 Copier：
+
+```go
+copier, err := copyx.New(
+    copyx.WithDeepCopy(),
+    copyx.WithFieldNames[Input, View](map[string]string{"Name": "DisplayName"}),
+    copyx.WithConverter(func(v time.Time) (string, error) {
+        return v.UTC().Format(time.RFC3339), nil
+    }),
+)
+if err != nil { return err }
+if err := copier.Copy(&view, input); err != nil { return err }
+```
+
+自定义函数的源/目标类型由 Go 泛型确定。深拷贝时返回原指针、原 map、子切片或嵌套旧引用都会报错；字符串/整数原值可以返回。差异规则、nil 策略、字段覆盖、资源限制和原 mapping 移除步骤见 [copyx 指南](COPY.md)，完整类型及可运行代码见 [examples/copying](examples/copying/main.go)。工具使用运行时检查，类型对需测试；深拷贝不适用于连接、锁等资源。
+
 ### 数据库、存储及其他模块
 
 生成项目在 `internal/svc` 中创建依赖，提供给 Logic/Repository，并用 `c.OnClose(db.Close)` 登记自有资源。生成的 main 在 HTTP 排空后关闭 svc，再关闭日志。直接使用框架的手写项目则可以用 `app.OnShutdown(db.Close)`；不要对同一资源重复登记。
@@ -467,7 +533,7 @@ go test ./...
 
 `main.go`、`Gen.go`、`docs/openapi.json` 和 manifest 由生成器管理，手动修改会报告冲突。Logic、Repository、中间件实现、配置和依赖装配属于项目，重复生成保留手写内容。契约变化会提示受影响的 Logic 文件和 DTO 字段，明确的签名错误会给出原签名与期望签名；生成后 `--check` 仍能检出未修复的问题。将 `.api`、`omni.gen.json`、生成文件和 `.goOmni/apiManifest.json` 一起提交，CI 同时运行 `generate --check` 与 `go test ./...`。详见 [契约变更提示与检查边界](PROJECT.md#契约变更提示)。
 
-CLI 与业务 module 固定使用 `v0.18.0-preview`。v0.14.x 项目升级依赖与 CLI 后重新生成，框架维护的 main/runtimeGen 自动更新；v0.13 及更早项目按 [升级预览](DEVELOPMENT.md#v013-项目升级) 处理，不直接覆盖手写入口或业务文件。升级后执行生成检查与业务回归。版本变化、迁移边界和验收记录见 [发布说明](RELEASE.md)。
+CLI 与业务 module 固定使用 `v0.19.0-preview`。v0.14.x 项目升级依赖与 CLI 后重新生成，框架维护的 main/runtimeGen 自动更新；v0.13 及更早项目按 [升级预览](DEVELOPMENT.md#v013-项目升级) 处理，不直接覆盖手写入口或业务文件。使用过旧 mapping 的项目必须先完成 [移除迁移](COPY.md#从旧-mapping-迁移)，旧配置或旧生成文件会阻止生成。升级后执行生成检查与业务回归。版本变化、迁移边界和验收记录见 [发布说明](RELEASE.md)。
 
 ## 按需深入
 
@@ -483,3 +549,7 @@ CLI 与业务 module 固定使用 `v0.18.0-preview`。v0.14.x 项目升级依赖
 | 网络性能、测试条件与适用范围 | [性能说明](PERFORMANCE.md)、[HTTP/2 验收](transport/native/HTTP2.md) |
 
 当前版本可用于固定版本接入与业务验证，仍标记为 preview。`.api` 借鉴 go-zero 的接口开发方式，支持范围以本仓库文档为准，不是完整 goctl 语法兼容层；HTTP/2 保持实验状态，OSS/R2 云账号实网验收不属于本次发布范围。
+
+## 后续开发约定
+
+每次功能开发完成，同步更新这份功能索引、用法说明、`examples/` 和发布记录；删除或改变功能必须注明影响与迁移。代码、示例和文档一起回归后再发布。约定已记录在 [AGENTS.md](AGENTS.md)，后续开发继续遵循。
diff --git a/RELEASE.md b/RELEASE.md
index f8e9e28..18248ae 100644
--- a/RELEASE.md
+++ b/RELEASE.md
@@ -1,4 +1,31 @@
-# v0.18.0-preview
+# v0.19.0-preview
+
+将可选结构转换改为直接 Go 调用，减少业务项目需要维护的配置。普通接口继续使用 `.api` 生成 DTO，不要求增加独立模型或任何拷贝规则。
+
+- 新增只依赖标准库的 `copyx`：Copy、Clone、可复用 Copier；浅/深拷贝、严格字段覆盖、nil/零值策略、字段改名、忽略字段、精确类型 converter。没有全局注册和隐式数字强转。
+- 深拷贝检查整个输入和输出图。自定义 converter 原样返回指针、map、slice，或新对象仍嵌套旧引用时返回错误；保留普通循环图，拒绝资源对象及超出遍历/估算分配预算的输入。
+- 转换失败不提交部分目标；保留错误路径和原始错误链。并发复用只共享不可变类型元数据；源/目标读写和 converter 副作用由调用方负责。
+- **不兼容变更：删除 mappings / mappingFiles、Go 类型加载与映射代码生成。** 检出旧配置/旧生成文件时给出迁移提示；不会静默删除业务正在使用的代码。公共字段组合、scalar、中间件工厂、Repository 选项保留。
+- README 补齐当前能力入口、解释和用法，新增 [完整 copyx 指南](COPY.md)、[可运行示例](examples/copying)；[AGENTS.md](AGENTS.md) 记录每次修改同步文档/示例/移除说明的约定。
+
+```sh
+go get git.yuntuo.hk/k2safe/go-omni@v0.19.0-preview
+go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.19.0-preview
+# 如用过旧 mapping，先按 COPY.md 完成迁移：
+go-omni api generate
+go-omni api generate --check
+go test ./...
+```
+
+迁移步骤和语义边界见 [copyx](COPY.md#从旧-mapping-迁移)。新工具做运行时检查，不能声称具备旧生成器的编译期字段覆盖保证；实际类型对必须有测试。独立三端工资示例验证金额精度、缺失/null/零值、空集合、错误链和字段新增；不修改或代替接入项目的完整业务回归。
+
+46 个测试包的全量 race（含实际生成项目）、vet/build、Go 1.22 兼容测试通过；30 秒 fuzz 无失败，14 种基准场景各测量三轮。验收条件、性能数据及本轮未覆盖的外部环境见 [v0.19 验收记录](reports/copyxAcceptance.md)。本版仍为 preview。
+
+---
+
+以下是历史版本记录，其中 mapping 功能已在 v0.19 移除，不应继续作为当前接入方式。
+
+# v0.18.0-preview（历史版本）
 
 补齐可空嵌套映射和按模块拆分配置，减少重复转换代码，业务空值规则仍由项目显式选择：
 
diff --git a/ROADMAP.md b/ROADMAP.md
index 8c55fe7..4e8bf70 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -1,5 +1,8 @@
 # GoOmni 成熟度计划
 
+当前发布基线为 v0.19.0-preview：普通接口通过 `.api` → DTO → Logic 开发；独立类型需要转换时可选 copyx。旧 JSON mapping 生成已移除，见 [迁移说明](COPY.md)。当前能力、使用入口和限制以 [README](README.md) 与 [发布记录](RELEASE.md) 为准。下文保留阶段性建设记录。
+
+
 当前进展：`v0.14.0-preview` 已完成契约驱动的业务开发能力、通用 Runtime/配置和官方 MySQL 适配器，并通过全量 race、实际生成服务及空缓存远程验收。新项目/升级以 [README](README.md) 和 [开发指南](DEVELOPMENT.md) 为准；下方为历史阶段记录，完整本轮验收见 [报告](reports/businessDevelopmentAcceptance.md)。具体 eTax/ePay 业务迁移与业务回归仍由接入项目完成。
 
 ## 1. 新项目启动与发布流程（已完成，v0.1.1）
diff --git a/cmd/go-omni/README.md b/cmd/go-omni/README.md
index 7ea2973..ea60944 100644
--- a/cmd/go-omni/README.md
+++ b/cmd/go-omni/README.md
@@ -1,8 +1,8 @@
 # go-omni CLI
 
-v0.18 新增：可空嵌套映射、`mappingFiles` 配置拆分、显式 nil 策略和可选 `pointerResult`。原 v0.17 配置继续有效，见 [生成能力指南](../../GENERATION.md)。
+v0.19 移除结构映射生成：`omni.gen.json` 只保留 Repository 和中间件选项。普通接口直接使用生成 DTO；需要类型转换时用普通 Go 或可选 [copyx](../../COPY.md)。旧 `mappings` / `mappingFiles` 必须按迁移步骤清理，CLI 不会静默删除仍在调用的旧生成文件。
 
-v0.17 增加公共字段组合、可选结构映射、自动中间件工厂和按需 Repository。配置和迁移见 [生成能力指南](../../GENERATION.md)。
+公共字段组合、中间件工厂和按需 Repository 继续支持，见 [生成能力指南](../../GENERATION.md)。
 
 v0.16 增加基础类型/动态 JSON 数组返回、OpenAPI 公共引用和 workspace Go Catalog 统一导出。见 [接入与筛选规则](../../DEVELOPMENT.md#同一份-go-错误目录供多个服务生成)。
 
@@ -14,7 +14,7 @@ v0.14 新增 `api format [--check]`、`api upgrade [--dry-run|--preview <空目
 
 ```sh
 # 仓库读取权限与 PATH 配置见根目录 README
-go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.18.0-preview
+go install git.yuntuo.hk/k2safe/go-omni/cmd/go-omni@v0.19.0-preview
 go-omni new --module example.com/hello ./hello
 
 # 从自己的契约生成；service.api 及其相对 import 文件需要在本地存在
@@ -49,14 +49,14 @@ main、Gen.go、OpenAPI 和 manifest 由生成器维护；业务文件按字节
 
 ## 版本与迁移
 
-CLI 与框架依赖固定使用 v0.18.0-preview。远程安装的 CLI 默认把自身版本写入 go.mod，不添加本地 replace；`--framework-version` 可显式指定已发布的兼容版本。仅在开发框架源码时使用本地替换：
+CLI 与框架依赖固定使用 v0.19.0-preview。远程安装的 CLI 默认把自身版本写入 go.mod，不添加本地 replace；`--framework-version` 可显式指定已发布的兼容版本。仅在开发框架源码时使用本地替换：
 
 ```sh
 # 在 go-omni 源码仓库中执行
 go run ./cmd/go-omni new --module example.com/hello --framework-dir . ../hello
 ```
 
-当前模板与依赖以 v0.18.0-preview 为基线，继续使用 manifest v2；GORM 可选适配器从 v0.14.1-preview 提供。已有项目使用 [定点升级与预览](../../DEVELOPMENT.md#v013-项目升级)：原始模板可自动替换，含业务修改的基础文件按预览合并；通用清理由 Runtime 负责。独立工具命令不会被删除。受管理项目通过 `.api` 模块导入增加业务，不使用旧 `add` 命令的手动路由装配。
+当前模板与依赖以 v0.19.0-preview 为基线，继续使用 manifest v2；GORM 可选适配器从 v0.14.1-preview 提供。已有项目使用 [定点升级与预览](../../DEVELOPMENT.md#v013-项目升级)：原始模板可自动替换，含业务修改的基础文件按预览合并；通用清理由 Runtime 负责。独立工具命令不会被删除。受管理项目通过 `.api` 模块导入增加业务，不使用旧 `add` 命令的手动路由装配。
 
 ## 数据库迁移命令
 
diff --git a/cmd/go-omni/apigen/copyConsumer_test.go b/cmd/go-omni/apigen/copyConsumer_test.go
new file mode 100644
index 0000000..629a907
--- /dev/null
+++ b/cmd/go-omni/apigen/copyConsumer_test.go
@@ -0,0 +1,95 @@
+package apigen
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+)
+
+func runConsumerGo(t *testing.T, dir string, args ...string) {
+	t.Helper()
+	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, "go", args...)
+	cmd.Dir = dir
+	cmd.Env = append(os.Environ(), "GOWORK=off")
+	if out, err := cmd.CombinedOutput(); err != nil {
+		t.Fatalf("go %v: %v\n%s", args, err, out)
+	}
+}
+func TestCopyxThreeEndpointConsumer(t *testing.T) {
+	if os.Getenv("GO_OMNI_SCAFFOLD_INTEGRATION") != "1" {
+		t.Skip("set GO_OMNI_SCAFFOLD_INTEGRATION=1")
+	}
+	dir := filepath.Join(t.TempDir(), "app")
+	o := Options{API: filepath.Join(frameworkRoot(t), "cmd/go-omni/apigen/testdata/composition/service.api"), Dir: dir, Module: "example.com/composition", FrameworkDir: frameworkRoot(t)}
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	for path, fixture := range map[string]string{
+		"internal/amount/money.go": "amount.go", "internal/domain/employee.go": "domain.go", "internal/convert/fields.go": "converters.go", "internal/convert/copy.go": "copy.go",
+		"internal/middleware/dependencies.go": "dependencies.go", "internal/middleware/accessFactory.go": "accessFactory.go", "internal/svc/client.go": "client.go", "consumer_test.go": "consumer_test.go",
+	} {
+		writeFile(t, filepath.Join(dir, path), readFile(t, "testdata/composition/"+fixture))
+	}
+	svcFile := filepath.Join(dir, "internal/svc/serviceContext.go")
+	source := strings.Replace(readFile(t, svcFile), "type ServiceContext struct {", "type ServiceContext struct {\n client *Client", 1)
+	source = strings.Replace(source, "return nil", "return c.initClient(ctx)", 1)
+	writeFile(t, svcFile, source)
+	configFile := filepath.Join(dir, "internal/config/config.go")
+	writeFile(t, configFile, strings.Replace(readFile(t, configFile), "type Config struct {", "type Config struct {\n FactoryMode string `json:\"factoryMode\"`", 1))
+	for _, group := range []string{"Enterprise", "Tenant", "Admin"} {
+		text := fmt.Sprintf(`package %s
+import("context";"example.com/composition/internal/types";"example.com/composition/internal/convert";"example.com/composition/internal/domain")
+func(s *Logic)Save(ctx context.Context,req *types.%sRequest)(*types.EmployeeResponse,error){
+ input,err:=convert.Employee(*req);if err!=nil{return nil,err}
+ result,err:=convert.Response(domain.Result{Employee:input,ID:9007199254740993});if err!=nil{return nil,err};return &result,nil
+}
+`, strings.ToLower(group), group)
+		writeFile(t, filepath.Join(dir, "internal/logic", strings.ToLower(group), "save.go"), text)
+	}
+	runConsumerGo(t, dir, "mod", "tidy")
+	runConsumerGo(t, dir, "test", "-race", "-count=1", "./...")
+	o.API = filepath.Join(dir, "api/service.api")
+	before := snapshot(t, dir)
+	o.DryRun = true
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	o.DryRun = false
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	o.Check = true
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	if !sameFiles(before, snapshot(t, dir)) {
+		t.Fatal("generation changed business files")
+	}
+	if _, err := os.Stat(filepath.Join(dir, "internal/mapping")); !os.IsNotExist(err) {
+		t.Fatal("mapping directory generated")
+	}
+	// Adding a common field requires one contract edit and one independent
+	// business field. Three endpoint converters need no new rules.
+	contract := readFile(t, o.API)
+	contract = strings.Replace(contract, "type SalaryFields {", "type SalaryFields {\n Note string `json:\"note,optional\"`", 1)
+	writeFile(t, o.API, contract)
+	domainPath := filepath.Join(dir, "internal/domain/employee.go")
+	writeFile(t, domainPath, strings.Replace(readFile(t, domainPath), "type Employee struct {", "type Employee struct {\n Note string", 1))
+	o.Check = false
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	o.Check = true
+	if err := generateManagedTestProject(t, o); err != nil {
+		t.Fatal(err)
+	}
+	runConsumerGo(t, dir, "test", "-race", "-count=1", "./...")
+	runConsumerGo(t, dir, "build", ".")
+}
diff --git a/cmd/go-omni/apigen/generate.go b/cmd/go-omni/apigen/generate.go
index 659bd9c..8509872 100644
--- a/cmd/go-omni/apigen/generate.go
+++ b/cmd/go-omni/apigen/generate.go
@@ -19,7 +19,7 @@ import (
 )
 
 const frameworkModule = "git.yuntuo.hk/k2safe/go-omni"
-const minimumVersion = "v0.18.0-preview"
+const minimumVersion = "v0.19.0-preview"
 const generatedHeader = "// Code generated by go-omni api. DO NOT EDIT.\n"
 
 type Options struct {
@@ -252,9 +252,6 @@ func generate(o Options, c *Compiled, starter bool) (Output, error) {
 			}
 		}
 	}
-	if err := renderMappings(o, generated, seeds); err != nil {
-		return Output{}, err
-	}
 	currentConfig, stillExists, err := readGeneratorConfig(directory)
 	if err != nil {
 		return Output{}, err
diff --git a/cmd/go-omni/apigen/generatorConfig.go b/cmd/go-omni/apigen/generatorConfig.go
index fc118ab..7a55c37 100644
--- a/cmd/go-omni/apigen/generatorConfig.go
+++ b/cmd/go-omni/apigen/generatorConfig.go
@@ -15,14 +15,11 @@ import (
 
 const generatorConfigFile = "omni.gen.json"
 
-// GeneratorConfig is developer-owned and checked on every generation. Mapping
-// rules never change the public API or infer a persistence model.
+// GeneratorConfig contains developer-owned scaffolding options only.
 type GeneratorConfig struct {
-	Repository   string    `json:"repository,omitempty"`
-	Middleware   string    `json:"middleware,omitempty"`
-	Mappings     []Mapping `json:"mappings,omitempty"`
-	MappingFiles []string  `json:"mappingFiles,omitempty"`
-	inputDigest  string
+	Repository  string `json:"repository,omitempty"`
+	Middleware  string `json:"middleware,omitempty"`
+	inputDigest string
 }
 
 func readGeneratorConfig(root string) (GeneratorConfig, bool, error) {
@@ -40,7 +37,7 @@ func readGeneratorConfig(root string) (GeneratorConfig, bool, error) {
 				return cfg, false, err
 			}
 			if previous.GeneratorConfig {
-				return cfg, false, errors.New("omni.gen.json is missing; restore the project-owned generation options and mappings before regenerating")
+				return cfg, false, errors.New("omni.gen.json is missing; restore the project-owned generation options before regenerating")
 			}
 			cfg.Middleware = "handlers"
 		} else if !errors.Is(e, os.ErrNotExist) {
@@ -54,72 +51,36 @@ func readGeneratorConfig(root string) (GeneratorConfig, bool, error) {
 	if !stat.Mode().IsRegular() || stat.Size() > 1<<20 {
 		return cfg, false, errors.New("omni.gen.json must be a regular file of at most 1 MiB")
 	}
-	raw, err := readMappingConfigFile(root, generatorConfigFile)
+	raw, err := readGeneratorConfigFile(root, generatorConfigFile)
 	if err != nil {
 		return cfg, false, err
 	}
+	var keys map[string]json.RawMessage
+	if err = apierrors.DecodeCatalogJSON(raw, &keys); err != nil {
+		return cfg, false, fmt.Errorf("omni.gen.json: %w", err)
+	}
+	for _, key := range []string{"mappings", "mappingFiles"} {
+		if _, exists := keys[key]; exists {
+			return cfg, false, errors.New("mapping generation was removed: migrate callers to copyx or ordinary Go, remove mappings/mappingFiles from omni.gen.json, then remove internal/mapping/mappingsGen.go; see COPY.md")
+		}
+	}
 	if err = apierrors.DecodeCatalogJSON(raw, &cfg); err != nil {
 		return cfg, false, fmt.Errorf("omni.gen.json: %w", err)
 	}
-	// Child files only declare mappings. No recursive imports, globs, implicit
-	// directory scans or access outside the project are supported.
-	if len(cfg.MappingFiles) > 64 {
-		return cfg, false, errors.New("omni.gen.json: at most 64 mappingFiles supported")
-	}
-	digest := sha256.New()
-	fmt.Fprintf(digest, "%s:%d:", generatorConfigFile, len(raw))
-	digest.Write(raw)
-	total := len(raw)
-	for i := range cfg.Mappings {
-		cfg.Mappings[i].origin = generatorConfigFile
-	}
-	seen := map[string]bool{generatorConfigFile: true}
-	for _, name := range cfg.MappingFiles {
-		key := strings.ToLower(name)
-		if seen[key] {
-			return cfg, false, fmt.Errorf("omni.gen.json: duplicate mapping file %q", name)
-		}
-		seen[key] = true
-		if !strings.HasSuffix(name, ".json") {
-			return cfg, false, fmt.Errorf("mapping file %q must have a .json extension", name)
-		}
-		data, err := readMappingConfigFile(root, name)
-		if err != nil {
-			return cfg, false, err
-		}
-		total += len(data)
-		if total > 4<<20 {
-			return cfg, false, errors.New("mapping configuration exceeds 4 MiB in total")
-		}
-		var file struct {
-			Mappings []Mapping `json:"mappings"`
-		}
-		if err = apierrors.DecodeCatalogJSON(data, &file); err != nil {
-			return cfg, false, fmt.Errorf("%s: %w (mapping files only support mappings; nested imports are not supported)", name, err)
-		}
-		for i := range file.Mappings {
-			file.Mappings[i].origin = name
-		}
-		cfg.Mappings = append(cfg.Mappings, file.Mappings...)
-		fmt.Fprintf(digest, "%s:%d:", name, len(data))
-		digest.Write(data)
-	}
-	cfg.inputDigest = fmt.Sprintf("%x", digest.Sum(nil))
+	digest := sha256.Sum256(raw)
+	cfg.inputDigest = fmt.Sprintf("%x", digest)
 	if cfg.Repository != "none" && cfg.Repository != "group" {
 		return cfg, false, errors.New("omni.gen.json: repository must be none or group")
 	}
 	if cfg.Middleware != "factories" && cfg.Middleware != "handlers" {
 		return cfg, false, errors.New("omni.gen.json: middleware must be factories or handlers")
 	}
-	if len(cfg.Mappings) > 128 {
-		return cfg, false, errors.New("omni.gen.json: at most 128 mappings supported")
-	}
 	return cfg, true, nil
 }
 
 // Read through a bounded reader as well as checking stat: a growing file cannot
 // make configuration loading unbounded. safePath also rejects symlink escapes.
-func readMappingConfigFile(root, name string) ([]byte, error) {
+func readGeneratorConfigFile(root, name string) ([]byte, error) {
 	if err := safePath(root, name); err != nil {
 		return nil, err
 	}
diff --git a/cmd/go-omni/apigen/generatorConfig_test.go b/cmd/go-omni/apigen/generatorConfig_test.go
index 069ad16..a797528 100644
--- a/cmd/go-omni/apigen/generatorConfig_test.go
+++ b/cmd/go-omni/apigen/generatorConfig_test.go
@@ -2,140 +2,95 @@ package apigen
 
 import (
 	"encoding/json"
-	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
 	"testing"
 )
 
-func TestMappingFileConfiguration(t *testing.T) {
-	dir := t.TempDir()
-	defs := nullableMappings()
-	writeGeneratorConfig(t, dir, GeneratorConfig{Repository: "none", Middleware: "factories", Mappings: defs[:1], MappingFiles: []string{"mappings/a.json", "mappings/b.json"}})
-	writeMappingFile(t, dir, "mappings/a.json", defs[1:5])
-	writeMappingFile(t, dir, "mappings/b.json", defs[5:])
-	first, exists, err := readGeneratorConfig(dir)
-	if err != nil || !exists || len(first.Mappings) != len(defs) {
-		t.Fatal(first, err)
-	}
-	for i, m := range first.Mappings {
-		if m.Name != defs[i].Name {
-			t.Fatal("non-deterministic load order")
+func TestWorkspaceRejectsRemovedMappingWithoutWrites(t *testing.T) {
+	root := t.TempDir()
+	for _, name := range []string{"one", "two"} {
+		if _, err := New(Options{Dir: filepath.Join(root, name), Module: "example.com/" + name, FrameworkDir: frameworkRoot(t)}); err != nil {
+			t.Fatal(err)
 		}
 	}
-	second, _, err := readGeneratorConfig(dir)
-	if err != nil || first.inputDigest != second.inputDigest {
-		t.Fatal("unstable config digest", err)
-	}
-	path := filepath.Join(dir, "mappings/a.json")
-	writeFile(t, path, readFile(t, path)+"\n")
-	changed, _, err := readGeneratorConfig(dir)
-	if err != nil || changed.inputDigest == first.inputDigest {
-		t.Fatal("child file change invisible to generation guard", err)
-	}
-	// Duplicate definitions name both files instead of silently overriding.
-	writeMappingFile(t, dir, "mappings/b.json", defs[1:2])
-	cfg, _, err := readGeneratorConfig(dir)
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = validateMappings(cfg.Mappings, "example.com/nullable")
-	if err == nil || !strings.Contains(err.Error(), "mappings/a.json") || !strings.Contains(err.Error(), "mappings/b.json") {
-		t.Fatal(err)
+	firstAPI := filepath.Join(root, "one/api/service.api")
+	writeFile(t, firstAPI, strings.Replace(readFile(t, firstAPI), "Greet a visitor", "Changed description", 1))
+	writeFile(t, filepath.Join(root, "two", generatorConfigFile), `{"mappingFiles":["../../private.json"]}`)
+	workspace := filepath.Join(root, "omni.workspace.json")
+	writeFile(t, workspace, `{"services":[{"dir":"one"},{"dir":"two"}]}`)
+	before := snapshot(t, root)
+	for _, operation := range []string{"generate", "check"} {
+		if err := Workspace(workspace, operation, io.Discard); err == nil || !strings.Contains(err.Error(), "mapping generation was removed") {
+			t.Fatal(operation, err)
+		}
+		if !sameFiles(before, snapshot(t, root)) {
+			t.Fatal("workspace migration failure wrote files")
+		}
 	}
 }
 
-func TestMappingFileRejection(t *testing.T) {
-	for _, tc := range []struct{ name, root, child, want string }{
-		{"missing", `{"mappingFiles":["maps.json"]}`, "", "maps.json"},
-		{"escape", `{"mappingFiles":["../maps.json"]}`, "", "unsafe"},
-		{"absolute", `{"mappingFiles":["/maps.json"]}`, "", "unsafe"},
-		{"nonCanonical", `{"mappingFiles":["sub/../maps.json"]}`, "", "unsafe"},
-		{"duplicate", `{"mappingFiles":["maps.json","maps.json"]}`, `{"mappings":[]}`, "duplicate mapping file"},
-		{"caseDuplicate", `{"mappingFiles":["maps.json","MAPS.json"]}`, `{"mappings":[]}`, "duplicate mapping file"},
-		{"self", `{"mappingFiles":["omni.gen.json"]}`, "", "duplicate mapping file"},
-		{"recursive", `{"mappingFiles":["maps.json"]}`, `{"mappingFiles":["omni.gen.json"]}`, "nested imports are not supported"},
-		{"childSettings", `{"mappingFiles":["maps.json"]}`, `{"repository":"none","mappings":[]}`, "maps.json"},
-		{"duplicateKeys", `{"mappingFiles":["maps.json"]}`, `{"mappings":[],"mappings":[]}`, "duplicate key"},
-		{"rootNull", `null`, "", "JSON object"},
-		{"childNull", `{"mappingFiles":["maps.json"]}`, `null`, "JSON object"},
-		{"unknownPolicy", `{"mappingFiles":["maps.json"]}`, `{"mappings":[{"unknown":true}]}`, "unknown field"},
-		{"trailingValue", `{"mappingFiles":["maps.json"]}`, `{"mappings":[]} {}`, "maps.json"},
-		{"tooLarge", `{"mappingFiles":["maps.json"]}`, strings.Repeat(" ", 1<<20) + `{}`, "1 MiB"},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			dir := t.TempDir()
-			writeFile(t, filepath.Join(dir, generatorConfigFile), tc.root)
-			if tc.child != "" {
-				writeFile(t, filepath.Join(dir, "maps.json"), tc.child)
-			}
-			before := snapshot(t, dir)
-			_, _, err := readGeneratorConfig(dir)
-			if err == nil || !strings.Contains(err.Error(), tc.want) {
+func TestRemovedMappingConfiguration(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "project")
+	if _, err := New(Options{Dir: dir, Module: "example.com/removed", FrameworkDir: frameworkRoot(t)}); err != nil {
+		t.Fatal(err)
+	}
+	for _, raw := range []string{`{"mappings":[]}`, `{"mappingFiles":[]}`, `{"mappings":null}`, `{"mappingFiles":["../../private.json"]}`} {
+		writeFile(t, filepath.Join(dir, generatorConfigFile), raw)
+		before := snapshot(t, dir)
+		for _, o := range []Options{{Dir: dir}, {Dir: dir, Check: true}, {Dir: dir, DryRun: true}} {
+			o.API = filepath.Join(dir, "api/service.api")
+			if _, err := Generate(o); err == nil || !strings.Contains(err.Error(), "mapping generation was removed") {
 				t.Fatal(err)
 			}
 			if !sameFiles(before, snapshot(t, dir)) {
-				t.Fatal("read changed configuration")
+				t.Fatal("rejected config wrote project")
 			}
-		})
-	}
-	for _, directory := range []bool{false, true} {
-		t.Run(fmt.Sprintf("symlinkDirectory%t", directory), func(t *testing.T) {
-			dir := t.TempDir()
-			outside := t.TempDir()
-			writeMappingFile(t, outside, "maps.json", nil)
-			name := "maps.json"
-			target := filepath.Join(outside, name)
-			link := filepath.Join(dir, name)
-			if directory {
-				name = "linked/maps.json"
-				target = outside
-				link = filepath.Join(dir, "linked")
-			}
-			if err := os.Symlink(target, link); err != nil {
-				t.Fatal(err)
-			}
-			writeGeneratorConfig(t, dir, GeneratorConfig{Repository: "none", Middleware: "factories", MappingFiles: []string{name}})
-			if _, _, err := readGeneratorConfig(dir); err == nil || !strings.Contains(err.Error(), "symlink") {
-				t.Fatal(err)
-			}
-		})
+		}
 	}
 }
-
-func TestMappingFileBounds(t *testing.T) {
-	dir := t.TempDir()
-	files := make([]string, 65)
-	for i := range files {
-		files[i] = fmt.Sprintf("maps%d.json", i)
-	}
-	writeGeneratorConfig(t, dir, GeneratorConfig{Repository: "none", Middleware: "factories", MappingFiles: files})
-	if _, _, err := readGeneratorConfig(dir); err == nil || !strings.Contains(err.Error(), "64") {
+func TestOldMappingFileRequiresExplicitMigration(t *testing.T) {
+	dir := filepath.Join(t.TempDir(), "project")
+	if _, err := New(Options{Dir: dir, Module: "example.com/removed", FrameworkDir: frameworkRoot(t)}); err != nil {
 		t.Fatal(err)
 	}
-	writeGeneratorConfig(t, dir, GeneratorConfig{Repository: "none", Middleware: "factories", MappingFiles: files[:4]})
-	for _, name := range files[:4] {
-		writeFile(t, filepath.Join(dir, name), `{"mappings":[]}`+strings.Repeat(" ", (1<<20)-len(`{"mappings":[]}`)))
-	}
-	if _, _, err := readGeneratorConfig(dir); err == nil || !strings.Contains(err.Error(), "4 MiB") {
+	name := "internal/mapping/mappingsGen.go"
+	body := generatedHeader + "package mapping\n"
+	writeFile(t, filepath.Join(dir, name), body)
+	var m manifest
+	if err := json.Unmarshal([]byte(readFile(t, filepath.Join(dir, manifestPath))), &m); err != nil {
 		t.Fatal(err)
 	}
-	// The definition limit applies after merging, not separately to each file.
-	defs := make([]Mapping, 129)
-	for i := range defs {
-		defs[i] = nullableMappings()[0]
-		defs[i].Name = fmt.Sprintf("Map%d", i)
+	m.Generated[name] = digest([]byte(body))
+	raw, _ := json.Marshal(m)
+	writeFile(t, filepath.Join(dir, manifestPath), string(raw))
+	before := snapshot(t, dir)
+	o := Options{Dir: dir, API: filepath.Join(dir, "api/service.api")}
+	for _, mode := range []string{"generate", "check", "dry-run"} {
+		o.Check = mode == "check"
+		o.DryRun = mode == "dry-run"
+		if _, err := Generate(o); err == nil || !strings.Contains(err.Error(), "mapping generation was removed") {
+			t.Fatal(err)
+		}
+		if !sameFiles(before, snapshot(t, dir)) {
+			t.Fatal("legacy file deleted or project changed")
+		}
 	}
-	writeGeneratorConfig(t, dir, GeneratorConfig{Repository: "none", Middleware: "factories", MappingFiles: files[:2]})
-	writeMappingFile(t, dir, files[0], defs[:65])
-	writeMappingFile(t, dir, files[1], defs[65:])
-	if _, _, err := readGeneratorConfig(dir); err == nil || !strings.Contains(err.Error(), "128") {
+	if err := os.Remove(filepath.Join(dir, name)); err != nil {
 		t.Fatal(err)
 	}
-	// Origins/digests are loader metadata, never serialized into user configuration.
-	raw, err := json.Marshal(GeneratorConfig{inputDigest: "private"})
-	if err != nil || strings.Contains(string(raw), "private") {
-		t.Fatal(string(raw), err)
+	o.Check = false
+	o.DryRun = false
+	if _, err := Generate(o); err != nil {
+		t.Fatal(err)
+	}
+	o.Check = true
+	if _, err := Generate(o); err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(readFile(t, filepath.Join(dir, manifestPath)), name) {
+		t.Fatal("old ownership retained")
 	}
 }
diff --git a/cmd/go-omni/apigen/mapping.go b/cmd/go-omni/apigen/mapping.go
deleted file mode 100644
index fea2733..0000000
--- a/cmd/go-omni/apigen/mapping.go
+++ /dev/null
@@ -1,453 +0,0 @@
-package apigen
-
-import (
-	"fmt"
-	"go/ast"
-	"go/format"
-	goparser "go/parser"
-	gotoken "go/token"
-	"go/types"
-	"sort"
-	"strconv"
-	"strings"
-
-	"golang.org/x/mod/module"
-)
-
-// GoTypeRef names an existing, exported, non-generic Go struct.
-type GoTypeRef struct {
-	Package string `json:"package"`
-	Type    string `json:"type"`
-}
-type GoFunctionRef struct {
-	Package string `json:"package"`
-	Name    string `json:"name"`
-}
-type MappingField struct {
-	Source   string         `json:"source"`
-	Convert  *GoFunctionRef `json:"convert,omitempty"`
-	Mapping  string         `json:"mapping,omitempty"`
-	Elements bool           `json:"elements,omitempty"`
-	Nil      string         `json:"nil,omitempty"`
-}
-type Mapping struct {
-	Name          string `json:"name"`
-	PointerResult bool   `json:"pointerResult,omitempty"`
-	origin        string
-	Source        GoTypeRef               `json:"source"`
-	Target        GoTypeRef               `json:"target"`
-	Fields        map[string]MappingField `json:"fields,omitempty"`
-	IgnoreSource  map[string]string       `json:"ignoreSource,omitempty"`
-	IgnoreTarget  map[string]string       `json:"ignoreTarget,omitempty"`
-}
-type mappingField struct {
-	path, name string
-	typ        types.Type
-}
-type mappingTypes struct{ source, target types.Type }
-type mappingRenderer struct {
-	importer    types.Importer
-	imports     map[string]string
-	definitions map[string]Mapping
-	types       map[string]mappingTypes
-}
-
-func renderMappings(o Options, generated, seeds map[string][]byte) error {
-	if len(o.generation.Mappings) == 0 {
-		return nil
-	}
-	refs, err := validateMappings(o.generation.Mappings, o.Module)
-	if err != nil {
-		return err
-	}
-	importer, close, err := loadMappingTypes(o, refs, generated, seeds)
-	if err != nil {
-		return err
-	}
-	defer close()
-	r := mappingRenderer{importer: importer, imports: map[string]string{}, definitions: map[string]Mapping{}, types: map[string]mappingTypes{}}
-	for _, m := range o.generation.Mappings {
-		source, err := r.lookup(m.Source)
-		if err != nil {
-			return err
-		}
-		target, err := r.lookup(m.Target)
-		if err != nil {
-			return err
-		}
-		r.definitions[m.Name] = m
-		r.types[m.Name] = mappingTypes{source, target}
-	}
-	names := make([]string, 0, len(r.definitions))
-	for name := range r.definitions {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-	var body strings.Builder
-	for _, name := range names {
-		source, err := r.render(r.definitions[name])
-		if err != nil {
-			return fmt.Errorf("%s: mapping %s: %w", mappingOrigin(r.definitions[name]), name, err)
-		}
-		body.WriteString(source)
-	}
-	imports := make([]string, 0, len(r.imports))
-	for path := range r.imports {
-		imports = append(imports, path)
-	}
-	sort.Strings(imports)
-	text := generatedHeader + "package mapping\nimport(\n"
-	for _, path := range imports {
-		text += r.imports[path] + " " + strconv.Quote(path) + "\n"
-	}
-	text += ")\n" + body.String()
-	code, err := format.Source([]byte(text))
-	if err != nil {
-		return fmt.Errorf("format mappings: %w", err)
-	}
-	// The generated package is type-checked before it is written. No application
-	// code (including init or converters) is executed during generation.
-	fset := gotoken.NewFileSet()
-	file, err := goparser.ParseFile(fset, "mappingsGen.go", code, 0)
-	if err != nil {
-		return err
-	}
-	check := types.Config{Importer: importer}
-	if _, err = check.Check(o.Module+"/internal/mapping", fset, []*ast.File{file}, nil); err != nil {
-		return fmt.Errorf("generated mapping type check: %w", err)
-	}
-	generated["internal/mapping/mappingsGen.go"] = code
-	return nil
-}
-
-func validateMappings(defs []Mapping, project string) ([]string, error) {
-	refs := map[string]bool{}
-	names := map[string]string{}
-	validPackage := func(path string) bool {
-		if module.CheckImportPath(path) != nil || path == project+"/internal/mapping" {
-			return false
-		}
-		// go/types does not enforce the compiler's internal import visibility.
-		if strings.HasPrefix(path, "internal/") {
-			return false
-		}
-		if i := strings.LastIndex(path, "/internal/"); i >= 0 {
-			return strings.HasPrefix(project+"/internal/mapping", path[:i]+"/")
-		}
-		return true
-	}
-	for _, m := range defs {
-		if !gotoken.IsIdentifier(m.Name) || !gotoken.IsExported(m.Name) {
-			return nil, fmt.Errorf("mapping name %q must be unique and exported", m.Name)
-		}
-		functions := []string{m.Name}
-		if m.PointerResult {
-			functions = append(functions, m.Name+"Ptr")
-		}
-		for _, name := range functions {
-			if prior, exists := names[name]; exists {
-				return nil, fmt.Errorf("mapping function %q must be unique: %s conflicts with %s", name, mappingOrigin(m), prior)
-			}
-			names[name] = mappingOrigin(m)
-		}
-		for _, ref := range []GoTypeRef{m.Source, m.Target} {
-			if !validPackage(ref.Package) || !gotoken.IsIdentifier(ref.Type) || !gotoken.IsExported(ref.Type) {
-				return nil, fmt.Errorf("mapping %s: invalid Go type reference", m.Name)
-			}
-			refs[ref.Package] = true
-		}
-		if len(m.Fields) > 4096 || len(m.IgnoreSource) > 4096 || len(m.IgnoreTarget) > 4096 {
-			return nil, fmt.Errorf("mapping %s: field rule limit exceeded", m.Name)
-		}
-		for target, f := range m.Fields {
-			if target == "" || f.Source == "" {
-				return nil, fmt.Errorf("mapping %s: explicit field rule requires target and source paths", m.Name)
-			}
-			if f.Nil != "" && f.Nil != "preserve" && f.Nil != "zero" && f.Nil != "error" {
-				return nil, fmt.Errorf("mapping %s.%s: nil must be preserve, zero or error", m.Name, target)
-			}
-			if f.Convert != nil && f.Nil != "" {
-				return nil, fmt.Errorf("mapping %s.%s: nil policy cannot be combined with a converter; the converter owns nil behavior", m.Name, target)
-			}
-			if f.Convert != nil {
-				if f.Mapping != "" || !validPackage(f.Convert.Package) || !gotoken.IsIdentifier(f.Convert.Name) || !gotoken.IsExported(f.Convert.Name) {
-					return nil, fmt.Errorf("mapping %s.%s: invalid or conflicting converter", m.Name, target)
-				}
-				refs[f.Convert.Package] = true
-			}
-		}
-	}
-	visiting, done := map[string]bool{}, map[string]bool{}
-	byName := map[string]Mapping{}
-	for _, m := range defs {
-		byName[m.Name] = m
-	}
-	var visit func(string) error
-	visit = func(name string) error {
-		if done[name] {
-			return nil
-		}
-		if visiting[name] {
-			return fmt.Errorf("mapping cycle at %s", name)
-		}
-		m, ok := byName[name]
-		if !ok {
-			return fmt.Errorf("unknown mapping %s", name)
-		}
-		visiting[name] = true
-		for _, f := range m.Fields {
-			if f.Mapping != "" {
-				if err := visit(f.Mapping); err != nil {
-					return err
-				}
-			}
-		}
-		delete(visiting, name)
-		done[name] = true
-		return nil
-	}
-	for _, m := range defs {
-		if err := visit(m.Name); err != nil {
-			return nil, err
-		}
-	}
-	out := make([]string, 0, len(refs))
-	for path := range refs {
-		out = append(out, path)
-	}
-	sort.Strings(out)
-	return out, nil
-}
-
-func (r *mappingRenderer) qualifier(p *types.Package) string {
-	if alias, ok := r.imports[p.Path()]; ok {
-		return alias
-	}
-	alias := fmt.Sprintf("pkg%d", len(r.imports))
-	r.imports[p.Path()] = alias
-	return alias
-}
-func (r *mappingRenderer) typeName(t types.Type) string { return types.TypeString(t, r.qualifier) }
-func (r *mappingRenderer) lookup(ref GoTypeRef) (types.Type, error) {
-	pkg, err := r.importer.Import(ref.Package)
-	if err != nil {
-		return nil, fmt.Errorf("mapping type %s.%s: %w", ref.Package, ref.Type, err)
-	}
-	obj, ok := pkg.Scope().Lookup(ref.Type).(*types.TypeName)
-	if !ok {
-		return nil, fmt.Errorf("mapping type %s.%s not found", ref.Package, ref.Type)
-	}
-	typ := obj.Type()
-	if n, ok := typ.(*types.Named); ok && n.TypeParams() != nil && n.TypeParams().Len() > 0 {
-		return nil, fmt.Errorf("mapping root %s must be a non-generic struct", ref.Type)
-	}
-	if _, ok := typ.Underlying().(*types.Struct); !ok {
-		return nil, fmt.Errorf("mapping root %s must be a struct", ref.Type)
-	}
-	return typ, nil
-}
-
-func mappingFields(typ types.Type) (map[string]mappingField, error) {
-	out := map[string]mappingField{}
-	leaves := map[string]string{}
-	var walk func(types.Type, string, int) error
-	walk = func(typ types.Type, prefix string, depth int) error {
-		if depth > 32 {
-			return fmt.Errorf("embedded field nesting exceeds 32")
-		}
-		st, ok := typ.Underlying().(*types.Struct)
-		if !ok {
-			return fmt.Errorf("embedded field %s must be a value struct", prefix)
-		}
-		for i := 0; i < st.NumFields(); i++ {
-			f := st.Field(i)
-			path := prefix + f.Name()
-			if !f.Exported() {
-				return fmt.Errorf("unexported field %s cannot be mapped; use an explicit converter on the containing value", path)
-			}
-			if f.Embedded() {
-				if err := walk(f.Type(), path+".", depth+1); err != nil {
-					return err
-				}
-				continue
-			}
-			if previous, exists := leaves[f.Name()]; exists {
-				return fmt.Errorf("ambiguous embedded fields %s and %s", previous, path)
-			}
-			leaves[f.Name()] = path
-			out[path] = mappingField{path, f.Name(), f.Type()}
-			if len(out) > 4096 {
-				return fmt.Errorf("mapping field limit exceeded")
-			}
-		}
-		return nil
-	}
-	if err := walk(typ, "", 0); err != nil {
-		return nil, err
-	}
-	return out, nil
-}
-
-func (r *mappingRenderer) render(m Mapping) (string, error) {
-	mt := r.types[m.Name]
-	source, err := mappingFields(mt.source)
-	if err != nil {
-		return "", err
-	}
-	target, err := mappingFields(mt.target)
-	if err != nil {
-		return "", err
-	}
-	for key, reason := range m.IgnoreSource {
-		if _, ok := source[key]; !ok || strings.TrimSpace(reason) == "" {
-			return "", fmt.Errorf("ignoreSource %s requires an existing field and reason", key)
-		}
-	}
-	for key, reason := range m.IgnoreTarget {
-		if _, ok := target[key]; !ok || strings.TrimSpace(reason) == "" {
-			return "", fmt.Errorf("ignoreTarget %s requires an existing field and reason", key)
-		}
-	}
-	for key := range m.Fields {
-		if _, ok := target[key]; !ok {
-			return "", fmt.Errorf("unknown target field %s", key)
-		}
-		if _, ignored := m.IgnoreTarget[key]; ignored {
-			return "", fmt.Errorf("target %s is both mapped and ignored", key)
-		}
-	}
-	names := make([]string, 0, len(target))
-	for name := range target {
-		names = append(names, name)
-	}
-	sort.Strings(names)
-	used := map[string]bool{}
-	text := fmt.Sprintf("// %s maps one value. Pointer/map/slice assignments retain Go reference semantics.\nfunc %s(source %s)(%s,error){\nvar result %s\n", m.Name, m.Name, r.typeName(mt.source), r.typeName(mt.target), r.typeName(mt.target))
-	for _, path := range names {
-		dst := target[path]
-		if reason, ignored := m.IgnoreTarget[path]; ignored {
-			text += "// Target " + path + " is intentionally left at zero; see omni.gen.json.\n"
-			_ = reason
-			continue
-		}
-		rule, explicit := m.Fields[path]
-		if !explicit {
-			for key, f := range source {
-				if f.name == dst.name {
-					rule.Source = key
-					break
-				}
-			}
-		}
-		src, ok := source[rule.Source]
-		if !ok {
-			return "", fmt.Errorf("target %s has no source; add a field rule or ignoreTarget reason", path)
-		}
-		if _, ignored := m.IgnoreSource[src.path]; ignored {
-			return "", fmt.Errorf("source %s is both mapped and ignored", src.path)
-		}
-		used[src.path] = true
-		from, to := src.typ, dst.typ
-		srcExpr, dstExpr := "source."+src.path, "result."+path
-		if rule.Elements {
-			switch d := to.Underlying().(type) {
-			case *types.Slice:
-				s, ok := from.Underlying().(*types.Slice)
-				if !ok {
-					return "", fmt.Errorf("%s: elements requires slice to slice or equal-length array to array", path)
-				}
-				text += fmt.Sprintf("if %s!=nil {\n%s=make(%s,len(%s))\nfor index:=range %s {\n", srcExpr, dstExpr, r.typeName(to), srcExpr, srcExpr)
-				from, to = s.Elem(), d.Elem()
-			case *types.Array:
-				s, ok := from.Underlying().(*types.Array)
-				if !ok || s.Len() != d.Len() {
-					return "", fmt.Errorf("%s: array lengths must match", path)
-				}
-				text += fmt.Sprintf("for index:=range %s {\n", srcExpr)
-				from, to = s.Elem(), d.Elem()
-			default:
-				return "", fmt.Errorf("%s: elements requires a slice or array", path)
-			}
-			srcExpr += "[index]"
-			dstExpr += "[index]"
-		}
-		expr, fallible, err := r.expression(rule, from, to, srcExpr)
-		if err != nil {
-			return "", fmt.Errorf("%s -> %s: %w", src.path, path, err)
-		}
-		if fallible {
-			fmtPkg, err := r.importer.Import("fmt")
-			if err != nil {
-				return "", err
-			}
-			alias := r.qualifier(fmtPkg)
-			message := m.Name + "." + path + ": %w"
-			args := "err"
-			if rule.Elements {
-				message = m.Name + "." + path + "[%d]: %w"
-				args = "index,err"
-			}
-			text += fmt.Sprintf("{ value,err:=%s\nif err!=nil{var zero %s;return zero,%s.Errorf(%q,%s)}\n%s=value\n}\n", expr, r.typeName(mt.target), alias, message, args, dstExpr)
-		} else {
-			text += dstExpr + "=" + expr + "\n"
-		}
-		if rule.Elements {
-			text += "}\n"
-			if _, ok := dst.typ.Underlying().(*types.Slice); ok {
-				text += "}\n"
-			}
-		}
-	}
-	keys := make([]string, 0, len(source))
-	for key := range source {
-		keys = append(keys, key)
-	}
-	sort.Strings(keys)
-	for _, key := range keys {
-		if !used[key] {
-			if _, ignored := m.IgnoreSource[key]; !ignored {
-				return "", fmt.Errorf("unmapped source field %s; map it or provide an ignoreSource reason", key)
-			}
-		}
-	}
-	text += "return result,nil\n}\n"
-	if m.PointerResult {
-		text += fmt.Sprintf("// %sPtr returns nil on conversion failure and otherwise a pointer to the result.\nfunc %sPtr(source %s)(*%s,error){\nvalue,err:=%s(source)\nif err!=nil{return nil,err}\nreturn &value,nil\n}\n", m.Name, m.Name, r.typeName(mt.source), r.typeName(mt.target), m.Name)
-	}
-	return text, nil
-}
-
-func (r *mappingRenderer) expression(rule MappingField, from, to types.Type, source string) (string, bool, error) {
-	if rule.Mapping != "" {
-		return r.nestedExpression(rule, from, to, source)
-	}
-	if rule.Nil != "" {
-		return r.dereferenceExpression(rule, from, to, source)
-	}
-	if rule.Convert != nil {
-		pkg, err := r.importer.Import(rule.Convert.Package)
-		if err != nil {
-			return "", false, err
-		}
-		fn, ok := pkg.Scope().Lookup(rule.Convert.Name).(*types.Func)
-		if !ok {
-			return "", false, fmt.Errorf("converter function %s not found", rule.Convert.Name)
-		}
-		sig := fn.Type().(*types.Signature)
-		if sig.Variadic() || (sig.TypeParams() != nil && sig.TypeParams().Len() > 0) || sig.Params().Len() != 1 || sig.Results().Len() < 1 || sig.Results().Len() > 2 {
-			return "", false, fmt.Errorf("converter must have signature func(Source) Target or func(Source) (Target,error)")
-		}
-		if !types.Identical(sig.Params().At(0).Type(), from) || !types.Identical(sig.Results().At(0).Type(), to) {
-			return "", false, fmt.Errorf("converter signature does not match field types")
-		}
-		fallible := sig.Results().Len() == 2
-		if fallible && !types.Identical(sig.Results().At(1).Type(), types.Universe.Lookup("error").Type()) {
-			return "", false, fmt.Errorf("converter second result must be error")
-		}
-		return r.qualifier(pkg) + "." + rule.Convert.Name + "(" + source + ")", fallible, nil
-	}
-	if !types.Identical(from, to) {
-		return "", false, fmt.Errorf("types %s and %s differ; provide an explicit converter", types.TypeString(from, nil), types.TypeString(to, nil))
-	}
-	return source, false, nil
-}
diff --git a/cmd/go-omni/apigen/mappingLoad.go b/cmd/go-omni/apigen/mappingLoad.go
deleted file mode 100644
index 320df90..0000000
--- a/cmd/go-omni/apigen/mappingLoad.go
+++ /dev/null
@@ -1,175 +0,0 @@
-package apigen
-
-import (
-	"bytes"
-	"context"
-	"encoding/json"
-	"errors"
-	"fmt"
-	"go/importer"
-	gotoken "go/token"
-	"go/types"
-	"io"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"sort"
-	"strings"
-	"time"
-
-	"golang.org/x/mod/modfile"
-)
-
-// loadMappingTypes uses the Go compiler's export data, including the pending
-// DTOs via an overlay. Module files and sum updates remain in a temporary dir.
-// It compiles only explicitly selected packages and their dependencies; never
-// runs project code. Build tags/GOOS follow the caller; GOWORK is disabled.
-func loadMappingTypes(o Options, refs []string, generated, seeds map[string][]byte) (types.Importer, func(), error) {
-	// go list resolves its working directory (notably /var -> /private/var on
-	// macOS). Overlay keys must name that same physical path or stale DTOs win.
-	o.Dir = canonical(o.Dir)
-	temp, err := os.MkdirTemp("", "go-omni-mapping-*")
-	if err != nil {
-		return nil, nil, err
-	}
-	cleanup := func() { _ = os.RemoveAll(temp) }
-	fail := func(err error) (types.Importer, func(), error) { cleanup(); return nil, nil, err }
-	raw, err := os.ReadFile(filepath.Join(o.Dir, "go.mod"))
-	if err != nil {
-		return fail(errors.New("mapping generation requires an existing Go module; scaffold first and resolve dependencies"))
-	}
-	mf, err := modfile.Parse("go.mod", raw, nil)
-	if err != nil {
-		return fail(err)
-	}
-	replacements := append([]*modfile.Replace(nil), mf.Replace...)
-	for _, r := range replacements {
-		if r.New.Version == "" && !filepath.IsAbs(r.New.Path) {
-			if err = mf.AddReplace(r.Old.Path, r.Old.Version, filepath.Join(o.Dir, r.New.Path), ""); err != nil {
-				return fail(err)
-			}
-		}
-	}
-	raw, err = mf.Format()
-	if err != nil {
-		return fail(err)
-	}
-	modPath := filepath.Join(temp, "go.mod")
-	if err = os.WriteFile(modPath, raw, 0600); err != nil {
-		return fail(err)
-	}
-	if sums, e := os.ReadFile(filepath.Join(o.Dir, "go.sum")); e == nil {
-		if err = os.WriteFile(filepath.Join(temp, "go.sum"), sums, 0600); err != nil {
-			return fail(err)
-		}
-	} else if !errors.Is(e, os.ErrNotExist) {
-		return fail(e)
-	}
-	overlay := map[string]string{}
-	// Hide stale owned Go files, which may otherwise redeclare a renamed DTO.
-	var previous manifest
-	if data, e := os.ReadFile(filepath.Join(o.Dir, manifestPath)); e == nil {
-		if err = json.Unmarshal(data, &previous); err != nil {
-			return fail(err)
-		}
-		for name := range previous.Generated {
-			if strings.HasSuffix(name, ".go") {
-				if !ownedPath(name) {
-					return fail(fmt.Errorf("invalid owned path %s", name))
-				}
-				if err = safePath(o.Dir, name); err != nil {
-					return fail(err)
-				}
-				if _, ok := generated[name]; !ok {
-					overlay[filepath.Join(o.Dir, filepath.FromSlash(name))] = ""
-				}
-			}
-		}
-	} else if !errors.Is(e, os.ErrNotExist) {
-		return fail(e)
-	}
-	for i, files := range []map[string][]byte{generated, seeds} {
-		names := make([]string, 0, len(files))
-		for name := range files {
-			if strings.HasSuffix(name, ".go") {
-				names = append(names, name)
-			}
-		}
-		sort.Strings(names)
-		for _, name := range names {
-			if err = safePath(o.Dir, name); err != nil {
-				return fail(err)
-			}
-			path := filepath.Join(o.Dir, filepath.FromSlash(name))
-			if i == 1 {
-				if _, e := os.Stat(path); e == nil {
-					continue
-				} else if !errors.Is(e, os.ErrNotExist) {
-					return fail(e)
-				}
-			}
-			backing := filepath.Join(temp, fmt.Sprintf("overlay%d.go", len(overlay)))
-			if err = os.WriteFile(backing, files[name], 0600); err != nil {
-				return fail(err)
-			}
-			overlay[path] = backing
-		}
-	}
-	raw, err = json.Marshal(map[string]any{"Replace": overlay})
-	if err != nil {
-		return fail(err)
-	}
-	overlayPath := filepath.Join(temp, "overlay.json")
-	if err = os.WriteFile(overlayPath, raw, 0600); err != nil {
-		return fail(err)
-	}
-	args := []string{"list", "-deps", "-export", "-json", "-mod=readonly", "-modfile", modPath, "-overlay", overlayPath}
-	// fmt is used for fallible conversions even if neither struct imports it.
-	args = append(args, "fmt")
-	args = append(args, refs...)
-	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
-	defer cancel()
-	cmd := exec.CommandContext(ctx, "go", args...)
-	cmd.Dir = o.Dir
-	cmd.Env = append(os.Environ(), "GOWORK=off")
-	cmd.WaitDelay = 2 * time.Second
-	stdout := &limitedCatalogBuffer{limit: 32 << 20}
-	stderr := &limitedCatalogBuffer{limit: 64 << 10}
-	cmd.Stdout = stdout
-	cmd.Stderr = stderr
-	if err = cmd.Run(); err != nil {
-		if ctx.Err() != nil {
-			return fail(fmt.Errorf("mapping type loading: %w", ctx.Err()))
-		}
-		// Go download errors may contain authenticated remote URLs. Keep arbitrary
-		// command output out of diagnostics; exact mapping errors follow type loading.
-		return fail(fmt.Errorf("mapping type loading failed (%v); run go list -deps -export for the configured source/target/converter packages; check dependencies, build tags and import cycles", err))
-	}
-	exports := map[string]string{}
-	dec := json.NewDecoder(bytes.NewReader(stdout.Bytes()))
-	for {
-		var p struct {
-			ImportPath, Export string
-			Error              *struct{ Err string }
-		}
-		if err = dec.Decode(&p); err == io.EOF {
-			break
-		} else if err != nil {
-			return fail(err)
-		}
-		if p.Error != nil {
-			return fail(fmt.Errorf("mapping package %s could not be compiled", p.ImportPath))
-		}
-		if p.Export != "" {
-			exports[p.ImportPath] = p.Export
-		}
-	}
-	imp := importer.ForCompiler(gotoken.NewFileSet(), "gc", func(path string) (io.ReadCloser, error) {
-		file, ok := exports[path]
-		if !ok {
-			return nil, fmt.Errorf("no export data for mapping dependency %s", path)
-		}
-		return os.Open(file)
-	})
-	return imp, cleanup, nil
-}
diff --git a/cmd/go-omni/apigen/mappingNullable_test.go b/cmd/go-omni/apigen/mappingNullable_test.go
deleted file mode 100644
index 23b1e53..0000000
--- a/cmd/go-omni/apigen/mappingNullable_test.go
+++ /dev/null
@@ -1,250 +0,0 @@
-package apigen
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"strings"
-	"testing"
-	"time"
-)
-
-func nullableMappings() []Mapping {
-	pkg := "example.com/nullable/internal/"
-	ref := func(p, name string) GoTypeRef { return GoTypeRef{pkg + p, name} }
-	child := Mapping{Name: "ToChild", Source: ref("types", "Child"), Target: ref("domain", "Child"), Fields: map[string]MappingField{
-		"Name": {Source: "Name", Convert: &GoFunctionRef{pkg + "convert", "Name"}},
-	}}
-	parent := Mapping{Name: "ToParent", PointerResult: true, Source: ref("types", "Parent"), Target: ref("domain", "Parent"), Fields: map[string]MappingField{
-		"Child": {Source: "Child", Mapping: "ToChild"}, "Children": {Source: "Children", Mapping: "ToChild", Elements: true},
-	}}
-	defs := []Mapping{child, parent,
-		{Name: "ToWireChild", Source: ref("domain", "Child"), Target: ref("types", "Child")},
-		{Name: "ToWire", PointerResult: true, Source: ref("domain", "Parent"), Target: ref("types", "Parent"), Fields: map[string]MappingField{
-			"Child": {Source: "Child", Mapping: "ToWireChild"}, "Children": {Source: "Children", Mapping: "ToWireChild", Elements: true},
-		}},
-		{Name: "ToChildDTO", Source: ref("domain", "Child"), Target: ref("domain", "ChildDTO"), Fields: map[string]MappingField{"Name": {Source: "Name", Convert: &GoFunctionRef{pkg + "convert", "Name"}}}},
-		{Name: "Lift", Source: ref("domain", "ValueHolder"), Target: ref("domain", "PointerHolder"), Fields: map[string]MappingField{"Child": {Source: "Child", Mapping: "ToChildDTO"}}},
-		{Name: "Batch", Source: ref("domain", "InputBatch"), Target: ref("domain", "OutputBatch"), Fields: map[string]MappingField{"Fixed": {Source: "Fixed", Mapping: "ToChildDTO", Elements: true}}},
-		{Name: "ShallowCopy", Source: ref("domain", "Parent"), Target: ref("domain", "Parent")},
-		{Name: "RequirePointer", Source: ref("types", "Parent"), Target: ref("domain", "Parent"), Fields: map[string]MappingField{
-			"Child": {Source: "Child", Mapping: "ToChild", Nil: "error"}, "Children": {Source: "Children", Mapping: "ToChild", Elements: true},
-		}},
-	}
-	for _, p := range []struct{ name, policy string }{{"RequiredZero", "zero"}, {"RequiredError", "error"}} {
-		defs = append(defs, Mapping{Name: p.name, Source: ref("types", "Parent"), Target: ref("domain", "Required"), Fields: map[string]MappingField{
-			"Child": {Source: "Child", Mapping: "ToChild", Nil: p.policy},
-		}, IgnoreSource: map[string]string{"Children": "this explicit projection only includes the child"}})
-	}
-	for _, p := range []struct{ name, policy string }{{"ScalarZero", "zero"}, {"ScalarError", "error"}} {
-		m := Mapping{Name: p.name, Source: ref("domain", "ScalarInput"), Target: ref("domain", "ScalarOutput"), Fields: map[string]MappingField{}}
-		for _, name := range []string{"Text", "Count", "Enabled"} {
-			m.Fields[name] = MappingField{Source: name, Nil: p.policy}
-		}
-		defs = append(defs, m)
-	}
-	return defs
-}
-
-func writeMappingFile(t *testing.T, root, name string, defs []Mapping) {
-	t.Helper()
-	raw, err := json.MarshalIndent(struct {
-		Mappings []Mapping `json:"mappings"`
-	}{defs}, "", "  ")
-	if err != nil {
-		t.Fatal(err)
-	}
-	writeFile(t, filepath.Join(root, name), string(raw)+"\n")
-}
-
-func TestNullableMappingConsumer(t *testing.T) {
-	if os.Getenv("GO_OMNI_SCAFFOLD_INTEGRATION") != "1" {
-		t.Skip("set GO_OMNI_SCAFFOLD_INTEGRATION=1")
-	}
-	root := t.TempDir()
-	dir := filepath.Join(root, "app")
-	o := Options{API: filepath.Join(frameworkRoot(t), "cmd/go-omni/apigen/testdata/nullable/service.api"), Dir: dir, Module: "example.com/nullable", FrameworkDir: frameworkRoot(t)}
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	for path, fixture := range map[string]string{"internal/domain/model.go": "domain.go", "internal/convert/value.go": "convert.go"} {
-		writeFile(t, filepath.Join(dir, path), readFile(t, "testdata/nullable/"+fixture))
-	}
-	runCompositionGo(t, dir, "mod", "tidy")
-	defs := nullableMappings()
-	// References go across files, including forward references to ToChild.
-	writeMappingFile(t, dir, "mappings/parents.json", defs[1:])
-	writeMappingFile(t, dir, "mappings/children.json", defs[:1])
-	cfg := GeneratorConfig{Repository: "none", Middleware: "factories", MappingFiles: []string{"mappings/parents.json", "mappings/children.json"}}
-	writeGeneratorConfig(t, dir, cfg)
-	o.API = filepath.Join(dir, "api/service.api")
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	writeFile(t, filepath.Join(dir, "internal/logic/probe/roundTrip.go"), `package probe
-import("context";"example.com/nullable/internal/types";"example.com/nullable/internal/mapping")
-func(s *Logic)RoundTrip(ctx context.Context,req *types.Parent)(*types.Parent,error){
- value,err:=mapping.ToParent(*req);if err!=nil{return nil,err}
- return mapping.ToWirePtr(value)
-}
-`)
-	writeFile(t, filepath.Join(dir, "consumer_test.go"), readFile(t, "testdata/nullable/consumer_test.go"))
-	before := snapshot(t, dir)
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("regeneration changed business/config files")
-	}
-	o.Check = true
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("check wrote files")
-	}
-	runCompositionGo(t, dir, "test", "-race", "-count=1", "./...")
-	runCompositionGo(t, dir, "build", ".")
-	// Workspace preflight and check use the same split configuration loader.
-	workspace := filepath.Join(root, "omni.workspace.json")
-	writeFile(t, workspace, `{"services":[{"dir":"app"}]}`)
-	for _, command := range []string{"format", "generate", "check"} {
-		if err := nullableWorkspace(t, workspace, command); err != nil {
-			t.Fatal(command, err)
-		}
-	}
-	// All invalid configurations fail before either writing or previewing output.
-	for _, tc := range []struct {
-		name, want string
-		edit       func([]Mapping) []Mapping
-	}{
-		{"missingNilPolicy", "requires explicit nil", func(d []Mapping) []Mapping {
-			d[9].Fields["Child"] = MappingField{Source: "Child", Mapping: "ToChild"}
-			return d
-		}},
-		{"preserveValue", "requires explicit nil", func(d []Mapping) []Mapping {
-			d[9].Fields["Child"] = MappingField{Source: "Child", Mapping: "ToChild", Nil: "preserve"}
-			return d
-		}},
-		{"zeroPointer", "pointer target", func(d []Mapping) []Mapping {
-			d[1].Fields["Child"] = MappingField{Source: "Child", Mapping: "ToChild", Nil: "zero"}
-			return d
-		}},
-		{"scalarMismatch", "identical *T to T", func(d []Mapping) []Mapping {
-			d[11].Fields["Text"] = MappingField{Source: "Count", Nil: "zero"}
-			return d
-		}},
-		{"valueNil", "requires a pointer source", func(d []Mapping) []Mapping {
-			d[5].Fields["Child"] = MappingField{Source: "Child", Mapping: "ToChildDTO", Nil: "zero"}
-			return d
-		}},
-		{"converterNil", "cannot be combined", func(d []Mapping) []Mapping {
-			f := d[0].Fields["Name"]
-			f.Nil = "error"
-			d[0].Fields["Name"] = f
-			return d
-		}},
-		{"pointerNameCollision", "must be unique", func(d []Mapping) []Mapping { m := d[0]; m.Name = "ToParentPtr"; return append(d, m) }},
-		{"mappingCycle", "cycle", func(d []Mapping) []Mapping {
-			d[0].Fields["Name"] = MappingField{Source: "Name", Mapping: "ToParent"}
-			return d
-		}},
-		{"unknownMapping", "unknown mapping", func(d []Mapping) []Mapping {
-			d[1].Fields["Child"] = MappingField{Source: "Child", Mapping: "Missing"}
-			return d
-		}},
-		{"unhandledField", "unmapped source", func(d []Mapping) []Mapping { d[9].IgnoreSource = nil; return d }},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			changed := tc.edit(nullableMappings())
-			writeMappingFile(t, dir, "mappings/parents.json", changed[1:])
-			writeMappingFile(t, dir, "mappings/children.json", changed[:1])
-			defer writeMappingFile(t, dir, "mappings/parents.json", defs[1:])
-			defer writeMappingFile(t, dir, "mappings/children.json", defs[:1])
-			before := snapshot(t, dir)
-			for _, mode := range []string{"check", "preview", "generate"} {
-				current := o
-				current.Check = mode == "check"
-				current.DryRun = mode == "preview"
-				err := generateManagedTestProject(t, current)
-				if err == nil || !strings.Contains(err.Error(), tc.want) {
-					t.Fatal(mode, err)
-				}
-				if !sameFiles(before, snapshot(t, dir)) {
-					t.Fatal("invalid mapping wrote files")
-				}
-			}
-		})
-	}
-	// An edit inside a child file is picked up by --check; the config is never rewritten.
-	changed := nullableMappings()
-	changed[0].PointerResult = true
-	writeMappingFile(t, dir, "mappings/children.json", changed[:1])
-	before = snapshot(t, dir)
-	if err := generateManagedTestProject(t, o); err == nil {
-		t.Fatal("check missed child mapping drift")
-	}
-	if err := nullableWorkspace(t, workspace, "check"); err == nil {
-		t.Fatal("workspace missed child mapping drift")
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("drift check wrote files")
-	}
-	preview := o
-	preview.Check = false
-	preview.DryRun = true
-	if err := generateManagedTestProject(t, preview); err != nil {
-		t.Fatal(err)
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("preview wrote files")
-	}
-	if err := nullableWorkspace(t, workspace, "generate"); err != nil {
-		t.Fatal(err)
-	}
-	if err := nullableWorkspace(t, workspace, "check"); err != nil {
-		t.Fatal(err)
-	}
-	if os.Getenv("GO_OMNI_RELEASE_CLI") != "" {
-		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-		defer cancel()
-		cmd := exec.CommandContext(ctx, "go", "list", "-m", "-json", frameworkModule)
-		cmd.Dir = dir
-		cmd.Env = append(os.Environ(), "GOWORK=off")
-		data, err := cmd.CombinedOutput()
-		if err != nil {
-			t.Fatal(err, string(data))
-		}
-		var dependency struct {
-			Version, Sum string
-			Replace      any
-		}
-		if err = json.Unmarshal(data, &dependency); err != nil {
-			t.Fatal(err)
-		}
-		if dependency.Version != os.Getenv("GO_OMNI_RELEASE_VERSION") || dependency.Replace != nil || dependency.Sum == "" {
-			t.Fatal("not a fixed remote consumer")
-		}
-		t.Logf("remote framework %s checksum %s; no local replace", dependency.Version, dependency.Sum)
-	}
-}
-
-func nullableWorkspace(t *testing.T, path, command string) error {
-	t.Helper()
-	cli := os.Getenv("GO_OMNI_RELEASE_CLI")
-	if cli == "" {
-		return Workspace(path, command, io.Discard)
-	}
-	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
-	defer cancel()
-	cmd := exec.CommandContext(ctx, cli, "workspace", command, "--file", path)
-	cmd.Dir = filepath.Dir(path)
-	if data, err := cmd.CombinedOutput(); err != nil {
-		return fmt.Errorf("released workspace CLI: %w\n%s", err, data)
-	}
-	return nil
-}
diff --git a/cmd/go-omni/apigen/mappingPointer.go b/cmd/go-omni/apigen/mappingPointer.go
deleted file mode 100644
index 10eb23a..0000000
--- a/cmd/go-omni/apigen/mappingPointer.go
+++ /dev/null
@@ -1,97 +0,0 @@
-package apigen
-
-import (
-	"fmt"
-	"go/types"
-)
-
-func mappingOrigin(m Mapping) string {
-	if m.origin != "" {
-		return m.origin
-	}
-	return generatorConfigFile
-}
-
-// Pointer adaptation is only selected by an explicit nested mapping. Ordinary
-// same-type pointer assignments retain their existing reference semantics.
-func (r *mappingRenderer) nestedExpression(rule MappingField, from, to types.Type, source string) (string, bool, error) {
-	m := r.types[rule.Mapping]
-	fromValue, toValue := from, to
-	src, sourcePointer := from.Underlying().(*types.Pointer)
-	dst, targetPointer := to.Underlying().(*types.Pointer)
-	if sourcePointer {
-		fromValue = src.Elem()
-	}
-	if targetPointer {
-		toValue = dst.Elem()
-	}
-	if !types.Identical(fromValue, m.source) || !types.Identical(toValue, m.target) {
-		return "", false, fmt.Errorf("nested mapping %s has incompatible types", rule.Mapping)
-	}
-	if !sourcePointer && rule.Nil != "" {
-		return "", false, fmt.Errorf("nil policy requires a pointer source")
-	}
-	if !sourcePointer && !targetPointer {
-		return rule.Mapping + "(" + source + ")", true, nil
-	}
-	policy := rule.Nil
-	if sourcePointer {
-		if targetPointer {
-			if policy == "" {
-				policy = "preserve"
-			}
-			if policy != "preserve" && policy != "error" {
-				return "", false, fmt.Errorf("pointer target requires nil preserve or error")
-			}
-		} else if policy != "zero" && policy != "error" {
-			return "", false, fmt.Errorf("pointer to value mapping requires explicit nil policy zero or error")
-		}
-	}
-	// Keep a typed local input so the source is evaluated once. The surrounding
-	// renderer adds the mapping/field/index error path and returns a zero parent.
-	body := "var zero " + r.typeName(to) + "\n"
-	input := "input"
-	if sourcePointer {
-		nilResult, err := r.nilResult(policy)
-		if err != nil {
-			return "", false, err
-		}
-		body += "if input==nil {" + nilResult + "}\n"
-		input = "*input"
-	}
-	body += "value,err:=" + rule.Mapping + "(" + input + ")\nif err!=nil{return zero,err}\n"
-	if targetPointer {
-		body += "return &value,nil\n"
-	} else {
-		body += "return value,nil\n"
-	}
-	return "func(input " + r.typeName(from) + ")(" + r.typeName(to) + ",error){\n" + body + "}(" + source + ")", true, nil
-}
-
-// A nil policy without a converter/mapping is deliberately limited to *T -> T.
-// It never casts numbers, changes named types, or invents business defaults.
-func (r *mappingRenderer) dereferenceExpression(rule MappingField, from, to types.Type, source string) (string, bool, error) {
-	pointer, ok := from.Underlying().(*types.Pointer)
-	if !ok || !types.Identical(pointer.Elem(), to) {
-		return "", false, fmt.Errorf("nil policy without a mapping requires identical *T to T types")
-	}
-	if rule.Nil != "zero" && rule.Nil != "error" {
-		return "", false, fmt.Errorf("pointer to value conversion requires nil zero or error")
-	}
-	nilResult, err := r.nilResult(rule.Nil)
-	if err != nil {
-		return "", false, err
-	}
-	return "func(input " + r.typeName(from) + ")(" + r.typeName(to) + ",error){\nvar zero " + r.typeName(to) + "\nif input==nil{" + nilResult + "}\nreturn *input,nil\n}(" + source + ")", true, nil
-}
-
-func (r *mappingRenderer) nilResult(policy string) (string, error) {
-	if policy != "error" {
-		return "return zero,nil", nil
-	}
-	pkg, err := r.importer.Import("fmt")
-	if err != nil {
-		return "", err
-	}
-	return "return zero," + r.qualifier(pkg) + ".Errorf(\"nil source is not allowed\")", nil
-}
diff --git a/cmd/go-omni/apigen/mapping_test.go b/cmd/go-omni/apigen/mapping_test.go
deleted file mode 100644
index 448aa5c..0000000
--- a/cmd/go-omni/apigen/mapping_test.go
+++ /dev/null
@@ -1,266 +0,0 @@
-package apigen
-
-import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"os"
-	"os/exec"
-	"path/filepath"
-	"strings"
-	"testing"
-	"time"
-)
-
-func compositionConfig() GeneratorConfig {
-	pkg := "example.com/composition/internal/"
-	cfg := GeneratorConfig{Repository: "none", Middleware: "factories"}
-	for _, name := range []string{"Enterprise", "Tenant", "Admin"} {
-		fields := map[string]MappingField{
-			"EmployeeName": {Source: "Name", Convert: &GoFunctionRef{pkg + "convert", "Name"}},
-			"Salary":       {Source: "Salary", Convert: &GoFunctionRef{pkg + "convert", "Money"}},
-			"Enabled":      {Source: "Enabled", Convert: &GoFunctionRef{pkg + "convert", "Bool"}},
-		}
-		m := Mapping{Name: "From" + name, Source: GoTypeRef{pkg + "types", name + "Request"}, Target: GoTypeRef{pkg + "domain", "Employee"}, Fields: fields}
-		if name != "Enterprise" {
-			m.IgnoreSource = map[string]string{"CompanyID": "Authorized separately by Logic; never copy path scope into body"}
-		}
-		cfg.Mappings = append(cfg.Mappings, m)
-	}
-	cfg.Mappings = append(cfg.Mappings, Mapping{Name: "ToResponse", Source: GoTypeRef{pkg + "domain", "Result"}, Target: GoTypeRef{pkg + "types", "EmployeeResponse"}, Fields: map[string]MappingField{"ID": {Source: "ID", Convert: &GoFunctionRef{pkg + "convert", "ID"}}}})
-	cfg.Mappings = append(cfg.Mappings, Mapping{Name: "ToRow", Source: GoTypeRef{pkg + "domain", "Row"}, Target: GoTypeRef{pkg + "domain", "RowDTO"}})
-	cfg.Mappings = append(cfg.Mappings, Mapping{Name: "ToBatch", Source: GoTypeRef{pkg + "domain", "Batch"}, Target: GoTypeRef{pkg + "domain", "BatchDTO"}, Fields: map[string]MappingField{
-		"Rows": {Source: "Rows", Mapping: "ToRow", Elements: true}, "Fixed": {Source: "Fixed", Mapping: "ToRow", Elements: true},
-	}})
-	return cfg
-}
-func writeGeneratorConfig(t *testing.T, dir string, cfg GeneratorConfig) {
-	t.Helper()
-	raw, err := json.MarshalIndent(cfg, "", "  ")
-	if err != nil {
-		t.Fatal(err)
-	}
-	writeFile(t, filepath.Join(dir, generatorConfigFile), string(raw)+"\n")
-}
-func runCompositionGo(t *testing.T, dir string, args ...string) {
-	t.Helper()
-	ctx, cancel := context.WithTimeout(context.Background(), 90*time.Second)
-	defer cancel()
-	cmd := exec.CommandContext(ctx, "go", args...)
-	cmd.Dir = dir
-	cmd.Env = append(os.Environ(), "GOWORK=off")
-	if out, err := cmd.CombinedOutput(); err != nil {
-		t.Fatalf("go %v: %v\n%s", args, err, out)
-	}
-}
-
-func TestCompositionMappingConsumer(t *testing.T) {
-	if os.Getenv("GO_OMNI_SCAFFOLD_INTEGRATION") != "1" {
-		t.Skip("set GO_OMNI_SCAFFOLD_INTEGRATION=1")
-	}
-	dir := filepath.Join(t.TempDir(), "app")
-	o := Options{API: filepath.Join(frameworkRoot(t), "cmd/go-omni/apigen/testdata/composition/service.api"), Dir: dir, Module: "example.com/composition", FrameworkDir: frameworkRoot(t)}
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	fixtures := map[string]string{
-		"internal/amount/money.go": "amount.go", "internal/domain/employee.go": "domain.go", "internal/convert/fields.go": "converters.go",
-		"internal/middleware/dependencies.go": "dependencies.go", "internal/middleware/accessFactory.go": "accessFactory.go", "internal/svc/client.go": "client.go", "consumer_test.go": "consumer_test.go",
-	}
-	for path, fixture := range fixtures {
-		writeFile(t, filepath.Join(dir, path), readFile(t, "testdata/composition/"+fixture))
-	}
-	svcFile := filepath.Join(dir, "internal/svc/serviceContext.go")
-	source := strings.Replace(readFile(t, svcFile), "type ServiceContext struct {", "type ServiceContext struct {\n client *Client", 1)
-	source = strings.Replace(source, "return nil", "return c.initClient(ctx)", 1)
-	writeFile(t, svcFile, source)
-	configFile := filepath.Join(dir, "internal/config/config.go")
-	writeFile(t, configFile, strings.Replace(readFile(t, configFile), "type Config struct {", "type Config struct {\n FactoryMode string `json:\"factoryMode\"`", 1))
-	// Resolve dependencies before opting into compile-time mapping. The first
-	// generation creates DTOs; the second sees current DTOs through an overlay.
-	// Logic does not yet import the generated mapping package.
-	testSource := readFile(t, filepath.Join(dir, "consumer_test.go"))
-	if err := os.Remove(filepath.Join(dir, "consumer_test.go")); err != nil {
-		t.Fatal(err)
-	}
-	runCompositionGo(t, dir, "mod", "tidy")
-	cfg := compositionConfig()
-	writeGeneratorConfig(t, dir, cfg)
-	o.API = filepath.Join(dir, "api/service.api")
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	writeFile(t, filepath.Join(dir, "consumer_test.go"), testSource)
-	for _, group := range []string{"Enterprise", "Tenant", "Admin"} {
-		text := fmt.Sprintf(`package %s
-import("context";"example.com/composition/internal/types";"example.com/composition/internal/mapping";"example.com/composition/internal/domain")
-func(s *Logic)Save(ctx context.Context,req *types.%sRequest)(*types.EmployeeResponse,error){
- input,err:=mapping.From%s(*req);if err!=nil{return nil,err}
- result,err:=mapping.ToResponse(domain.Result{Employee:input,ID:9007199254740993});if err!=nil{return nil,err};return &result,nil
-}
-`, strings.ToLower(group), group, group)
-		writeFile(t, filepath.Join(dir, "internal/logic", strings.ToLower(group), "save.go"), text)
-	}
-	before := snapshot(t, dir)
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("regeneration changed project")
-	}
-	o.Check = true
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if !sameFiles(before, snapshot(t, dir)) {
-		t.Fatal("check changed project")
-	}
-	runCompositionGo(t, dir, "test", "-race", "-count=1", "./...")
-	runCompositionGo(t, dir, "build", ".")
-	generated := readFile(t, filepath.Join(dir, "internal/mapping/mappingsGen.go"))
-	if strings.Contains(generated, "encoding/json") || strings.Contains(generated, "reflect") || !strings.Contains(generated, "result.EmployeeName = value") {
-		t.Fatal("mapping does not emit typed assignments")
-	}
-	// Adding a source or target field is detected before any files are written.
-	for _, tc := range []struct{ name, path, before, after, want string }{
-		{"source", o.API, "Name *string", "NewField *string `json:\"newField,optional\"`\n Name *string", "unmapped source field NewField"},
-		{"target", filepath.Join(dir, "internal/domain/employee.go"), "EmployeeName string", "Unmapped string\n EmployeeName string", "target Unmapped has no source"},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			original := readFile(t, tc.path)
-			writeFile(t, tc.path, strings.Replace(original, tc.before, tc.after, 1))
-			defer writeFile(t, tc.path, original)
-			snap := snapshot(t, dir)
-			if err := generateManagedTestProject(t, o); err == nil || !strings.Contains(err.Error(), tc.want) {
-				t.Fatal(err)
-			}
-			if !sameFiles(snap, snapshot(t, dir)) {
-				t.Fatal("failed check wrote files")
-			}
-			o.Check = false
-			defer func() { o.Check = true }()
-			if err := generateManagedTestProject(t, o); err == nil {
-				t.Fatal("generate accepted missing mapping")
-			}
-			if !sameFiles(snap, snapshot(t, dir)) {
-				t.Fatal("failed generate wrote files")
-			}
-		})
-	}
-	for _, tc := range []struct {
-		name string
-		edit func(*GeneratorConfig)
-		want string
-	}{
-		{"pointerPolicy", func(c *GeneratorConfig) { delete(c.Mappings[0].Fields, "Salary") }, "provide an explicit converter"},
-		{"unknownSource", func(c *GeneratorConfig) { c.Mappings[0].Fields["Salary"] = MappingField{Source: "Missing"} }, "has no source"},
-		{"wrongConverter", func(c *GeneratorConfig) {
-			f := c.Mappings[0].Fields["Salary"]
-			f.Convert.Name = "ID"
-			c.Mappings[0].Fields["Salary"] = f
-		}, "signature does not match"},
-		{"unhandledScope", func(c *GeneratorConfig) { c.Mappings[1].IgnoreSource = nil }, "unmapped source field CompanyID"},
-		{"badIgnore", func(c *GeneratorConfig) { c.Mappings[1].IgnoreSource["Missing"] = "stale rule" }, "ignoreSource Missing"},
-		{"arrayLength", func(c *GeneratorConfig) {
-			f := c.Mappings[5].Fields["Fixed"]
-			f.Source = "Rows"
-			c.Mappings[5].Fields["Fixed"] = f
-		}, "array lengths must match"},
-	} {
-		t.Run(tc.name, func(t *testing.T) {
-			changed := compositionConfig()
-			tc.edit(&changed)
-			writeGeneratorConfig(t, dir, changed)
-			defer writeGeneratorConfig(t, dir, cfg)
-			snap := snapshot(t, dir)
-			if err := generateManagedTestProject(t, o); err == nil || !strings.Contains(err.Error(), tc.want) {
-				t.Fatal(err)
-			}
-			if !sameFiles(snap, snapshot(t, dir)) {
-				t.Fatal("invalid rule wrote files")
-			}
-		})
-	}
-	// All diagnostics exercise current DTOs, not stale exported generated types.
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	// Exercise the repository switch with the same actual CLI as the mapper.
-	if _, err := os.Stat(filepath.Join(dir, "internal/repository")); !os.IsNotExist(err) {
-		t.Fatalf("default repository skeleton: %v", err)
-	}
-	o.Check = false
-	cfg.Repository = "group"
-	writeGeneratorConfig(t, dir, cfg)
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	repo := filepath.Join(dir, "internal/repository/enterprise/repository.go")
-	writeFile(t, repo, readFile(t, repo)+"\n// Project-owned persistence.\n")
-	cfg.Repository = "none"
-	writeGeneratorConfig(t, dir, cfg)
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if !strings.Contains(readFile(t, repo), "Project-owned persistence.") {
-		t.Fatal("disabling skeleton overwrote business code")
-	}
-	o.Check = true
-	if err := generateManagedTestProject(t, o); err != nil {
-		t.Fatal(err)
-	}
-	if os.Getenv("GO_OMNI_RELEASE_CLI") != "" {
-		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
-		defer cancel()
-		cmd := exec.CommandContext(ctx, "go", "list", "-m", "-json", frameworkModule)
-		cmd.Dir = dir
-		cmd.Env = append(os.Environ(), "GOWORK=off")
-		data, err := cmd.CombinedOutput()
-		if err != nil {
-			t.Fatal(err, string(data))
-		}
-		var dependency struct {
-			Version, Sum string
-			Replace      any
-		}
-		if err = json.Unmarshal(data, &dependency); err != nil {
-			t.Fatal(err)
-		}
-		if dependency.Version != os.Getenv("GO_OMNI_RELEASE_VERSION") || dependency.Replace != nil || dependency.Sum == "" {
-			t.Fatal("not a fixed remote consumer")
-		}
-		t.Logf("remote framework %s checksum %s; no local replace", dependency.Version, dependency.Sum)
-	}
-}
-
-func TestMappingConfigurationRejection(t *testing.T) {
-	cases := []struct {
-		name string
-		edit func(*GeneratorConfig)
-		want string
-	}{
-		{"cycle", func(c *GeneratorConfig) {
-			c.Mappings[4].Fields = map[string]MappingField{"Value": {Source: "Value", Mapping: "ToRow"}}
-		}, "cycle"},
-		{"unknown", func(c *GeneratorConfig) {
-			c.Mappings[5].Fields["Rows"] = MappingField{Source: "Rows", Mapping: "Missing", Elements: true}
-		}, "unknown mapping"},
-		{"conflict", func(c *GeneratorConfig) {
-			f := c.Mappings[0].Fields["Salary"]
-			f.Mapping = "ToRow"
-			c.Mappings[0].Fields["Salary"] = f
-		}, "conflicting converter"},
-		{"internal", func(c *GeneratorConfig) { c.Mappings[0].Source.Package = "example.net/private/internal/types" }, "invalid Go type"},
-		{"outputCycle", func(c *GeneratorConfig) { c.Mappings[0].Source.Package = "example.com/composition/internal/mapping" }, "invalid Go type"},
-		{"duplicates", func(c *GeneratorConfig) { c.Mappings[1].Name = c.Mappings[0].Name }, "must be unique"},
-	}
-	for _, tc := range cases {
-		t.Run(tc.name, func(t *testing.T) {
-			cfg := compositionConfig()
-			tc.edit(&cfg)
-			if _, err := validateMappings(cfg.Mappings, "example.com/composition"); err == nil || !strings.Contains(err.Error(), tc.want) {
-				t.Fatal(err)
-			}
-		})
-	}
-}
diff --git a/cmd/go-omni/apigen/templates.go b/cmd/go-omni/apigen/templates.go
index c1bfee6..1c53758 100644
--- a/cmd/go-omni/apigen/templates.go
+++ b/cmd/go-omni/apigen/templates.go
@@ -56,10 +56,11 @@ factories for new projects. Named middleware factories run after svc.Init;
 implement Dependencies accessors on ServiceContext and New<Name>(deps) once.
 Unimplemented/nil factories fail startup and clean registered dependencies.
 Existing projects retain middleware: handlers until explicitly migrated.
-Optional mappings generate typed assignments in internal/mapping/mappingsGen.go;
-configure source/target types and explicit conversion rules after resolving module
-dependencies. Missing fields fail generation and --check. See GENERATION.md in
-the framework repository for composition, null/reference semantics and migration.
+Ordinary Logic uses the generated Request/Response types directly. Where an
+independent business type is needed, use ordinary Go or the optional copyx package.
+There are no mappings/mappingFiles settings or generated mapping files in v0.19.
+See COPY.md in the framework repository for copy policies and migration steps,
+and GENERATION.md for field composition and middleware factories.
 
 ## Run
 
@@ -145,8 +146,7 @@ internal/handler/<group>/     # generated binding and Logic adapters
 internal/logic/<group>/      # developer-owned business operations
 internal/repository/<group>/  # optional; repository: group creates editable seeds
 internal/middleware/         # typed dependency interface, factories and registry
-omni.gen.json                # developer-owned generator options and mappings
-internal/mapping/*Gen.go      # optional compile-checked struct mappings
+omni.gen.json                # developer-owned repository/middleware options
 docs/openapi.json             # generated OpenAPI 3.0.3
 .goOmni/apiManifest.json      # ownership and content hashes
 `+"```"+`
diff --git a/cmd/go-omni/apigen/testdata/composition/consumer_test.go b/cmd/go-omni/apigen/testdata/composition/consumer_test.go
index ee451d0..2eec80a 100644
--- a/cmd/go-omni/apigen/testdata/composition/consumer_test.go
+++ b/cmd/go-omni/apigen/testdata/composition/consumer_test.go
@@ -18,7 +18,6 @@ import (
 	"example.com/composition/internal/convert"
 	"example.com/composition/internal/domain"
 	"example.com/composition/internal/handler"
-	"example.com/composition/internal/mapping"
 	"example.com/composition/internal/middleware"
 	"example.com/composition/internal/svc"
 	"example.com/composition/internal/types"
@@ -86,16 +85,16 @@ func TestHTTPComposition(t *testing.T) {
 		}
 	}
 }
-func TestFullFormAndMappingSemantics(t *testing.T) {
+func TestFullFormAndCopySemantics(t *testing.T) {
 	name := "employee"
 	money := amount.Money("2.00")
 	yes := true
 	req := types.EnterpriseRequest{Name: &name, Salary: &money, Enabled: &yes, Labels: []string{"one"}}
-	first, e := mapping.FromEnterprise(req)
+	first, e := convert.Employee(req)
 	if e != nil {
 		t.Fatal(e)
 	}
-	second, e := mapping.FromEnterprise(types.EnterpriseRequest{})
+	second, e := convert.Employee(types.EnterpriseRequest{})
 	if e != nil {
 		t.Fatal(e)
 	}
@@ -108,26 +107,26 @@ func TestFullFormAndMappingSemantics(t *testing.T) {
 		t.Fatal("unexpected implicit deep copy")
 	}
 	req.Employer = &money
-	first, e = mapping.FromEnterprise(req)
+	first, e = convert.Employee(req)
 	if e != nil || first.Employer != req.Employer {
 		t.Fatal("nullable pointer changed", e)
 	}
 	bad := "reject"
-	failed, e := mapping.FromEnterprise(types.EnterpriseRequest{Name: &bad})
+	failed, e := convert.Employee(types.EnterpriseRequest{Name: &bad})
 	if !errors.Is(e, convert.ErrName) || failed.EmployeeName != "" || !strings.Contains(e.Error(), "EmployeeName") {
 		t.Fatal("converter cause/zero result lost", e)
 	}
-	empty, e := mapping.ToBatch(domain.Batch{})
+	empty, e := convert.ToBatch(domain.Batch{})
 	if e != nil || empty.Rows != nil {
 		t.Fatal("nil slice changed", e)
 	}
 	src := domain.Batch{Rows: []domain.Row{}, Fixed: [2]domain.Row{{Value: "a"}, {Value: "b"}}, Optional: &name}
-	out, e := mapping.ToBatch(src)
+	out, e := convert.ToBatch(src)
 	if e != nil || out.Rows == nil || len(out.Rows) != 0 || out.Fixed[1].Value != "b" || out.Optional != src.Optional {
 		t.Fatal(out, e)
 	}
 	src.Rows = []domain.Row{{Value: "one"}}
-	out, e = mapping.ToBatch(src)
+	out, e = convert.ToBatch(src)
 	if e != nil || out.Rows[0].Value != "one" {
 		t.Fatal(out, e)
 	}
@@ -140,7 +139,7 @@ func TestFullFormAndMappingSemantics(t *testing.T) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
-			result, err := mapping.FromEnterprise(types.EnterpriseRequest{Name: &name, Salary: &money})
+			result, err := convert.Employee(types.EnterpriseRequest{Name: &name, Salary: &money})
 			if err != nil || result.EmployeeName != name || result.Salary != money {
 				t.Error(result, err)
 			}
diff --git a/cmd/go-omni/apigen/testdata/composition/converters.go b/cmd/go-omni/apigen/testdata/composition/converters.go
index c26a9ca..f3c520f 100644
--- a/cmd/go-omni/apigen/testdata/composition/converters.go
+++ b/cmd/go-omni/apigen/testdata/composition/converters.go
@@ -2,7 +2,6 @@ package convert
 
 import (
 	"errors"
-	"example.com/composition/internal/amount"
 	"strconv"
 )
 
@@ -19,11 +18,4 @@ func Name(value *string) (string, error) {
 	}
 	return *value, nil
 }
-func Money(value *amount.Money) amount.Money {
-	if value == nil {
-		return ""
-	}
-	return *value
-}
-func Bool(value *bool) bool { return value != nil && *value }
 func ID(value int64) string { return strconv.FormatInt(value, 10) }
diff --git a/cmd/go-omni/apigen/testdata/composition/copy.go b/cmd/go-omni/apigen/testdata/composition/copy.go
new file mode 100644
index 0000000..1bd8c8c
--- /dev/null
+++ b/cmd/go-omni/apigen/testdata/composition/copy.go
@@ -0,0 +1,29 @@
+package convert
+
+import (
+	"example.com/composition/internal/domain"
+	"example.com/composition/internal/types"
+	"git.yuntuo.hk/k2safe/go-omni/copyx"
+)
+
+// The three endpoints reuse one ordinary Go helper and their existing scalar.
+// There is no field list or package/type name JSON to keep in sync.
+func Employee[S any](source S) (domain.Employee, error) {
+	var target domain.Employee
+	err := copyx.Copy(&target, source,
+		copyx.WithFieldNames[S, domain.Employee](map[string]string{"Name": "EmployeeName"}),
+		copyx.WithNilPolicy(copyx.NilZero),
+		copyx.WithConverter(Name),
+	)
+	return target, err
+}
+func Response(source domain.Result) (types.EmployeeResponse, error) {
+	var target types.EmployeeResponse
+	err := copyx.Copy(&target, source, copyx.WithConverter(func(v int64) (string, error) { return ID(v), nil }))
+	return target, err
+}
+func ToBatch(source domain.Batch) (domain.BatchDTO, error) {
+	var target domain.BatchDTO
+	err := copyx.Copy(&target, source)
+	return target, err
+}
diff --git a/cmd/go-omni/apigen/testdata/composition/domain.go b/cmd/go-omni/apigen/testdata/composition/domain.go
index 25c891b..6400079 100644
--- a/cmd/go-omni/apigen/testdata/composition/domain.go
+++ b/cmd/go-omni/apigen/testdata/composition/domain.go
@@ -14,7 +14,7 @@ type Result struct {
 	ID int64
 }
 
-// Distinct container item types exercise explicitly selected element mappings.
+// Distinct container item types exercise explicit Go collection copying.
 type Row struct{ Value string }
 type RowDTO struct{ Value string }
 type Batch struct {
diff --git a/cmd/go-omni/apigen/testdata/nullable/consumer_test.go b/cmd/go-omni/apigen/testdata/nullable/consumer_test.go
deleted file mode 100644
index 1a552cf..0000000
--- a/cmd/go-omni/apigen/testdata/nullable/consumer_test.go
+++ /dev/null
@@ -1,170 +0,0 @@
-package main
-
-import (
-	"context"
-	"encoding/json"
-	"errors"
-	"io"
-	"net/http/httptest"
-	"strings"
-	"sync"
-	"testing"
-
-	"example.com/nullable/internal/convert"
-	"example.com/nullable/internal/domain"
-	"example.com/nullable/internal/handler"
-	"example.com/nullable/internal/mapping"
-	"example.com/nullable/internal/svc"
-	"example.com/nullable/internal/types"
-	"git.yuntuo.hk/k2safe/go-omni/logx"
-)
-
-func TestNullableMappings(t *testing.T) {
-	for _, src := range []types.Parent{{}, {Children: []*types.Child{}}, {Child: &types.Child{}, Children: []*types.Child{nil, {Name: "two"}}}} {
-		out, err := mapping.ToParent(src)
-		if err != nil || (src.Child == nil) != (out.Child == nil) || (src.Children == nil) != (out.Children == nil) || len(src.Children) != len(out.Children) {
-			t.Fatal(src, out, err)
-		}
-		if src.Child != nil && out.Child.Name != src.Child.Name {
-			t.Fatal("zero child changed")
-		}
-		if len(out.Children) > 0 && (out.Children[0] != nil || out.Children[1].Name != "two") {
-			t.Fatal(out)
-		}
-	}
-	src := types.Parent{Child: &types.Child{Name: "one"}, Children: []*types.Child{{Name: "two"}}}
-	out, err := mapping.ToParentPtr(src)
-	if err != nil || out == nil || out.Child.Name != "one" {
-		t.Fatal(out, err)
-	}
-	out.Child.Name = "changed"
-	out.Children[0].Name = "changed"
-	if src.Child.Name != "one" || src.Children[0].Name != "two" {
-		t.Fatal("nested mapped values alias input")
-	}
-	plain := domain.Parent{Child: &domain.Child{Name: "shared"}}
-	copy, err := mapping.ShallowCopy(plain)
-	if err != nil || copy.Child != plain.Child {
-		t.Fatal("ordinary assignment semantics changed", err)
-	}
-	zero, err := mapping.RequiredZero(types.Parent{})
-	if err != nil || zero.Child.Name != "" {
-		t.Fatal(zero, err)
-	}
-	for _, fn := range []func(types.Parent) (domain.Required, error){mapping.RequiredZero, mapping.RequiredError} {
-		out, err := fn(types.Parent{Child: &types.Child{Name: "required"}})
-		if err != nil || out.Child.Name != "required" {
-			t.Fatal(out, err)
-		}
-	}
-	_, err = mapping.RequiredError(types.Parent{})
-	if err == nil || !strings.Contains(err.Error(), "RequiredError.Child") {
-		t.Fatal(err)
-	}
-	_, err = mapping.RequirePointer(types.Parent{})
-	if err == nil || !strings.Contains(err.Error(), "RequirePointer.Child") {
-		t.Fatal(err)
-	}
-	lift, err := mapping.Lift(domain.ValueHolder{Child: domain.Child{Name: "lift"}})
-	if err != nil || lift.Child == nil || lift.Child.Name != "lift" {
-		t.Fatal(lift, err)
-	}
-	batch, err := mapping.Batch(domain.InputBatch{Fixed: [2]*domain.Child{nil, {Name: "array"}}})
-	if err != nil || batch.Fixed[0] != nil || batch.Fixed[1].Name != "array" {
-		t.Fatal(batch, err)
-	}
-	_, err = mapping.Batch(domain.InputBatch{Fixed: [2]*domain.Child{nil, {Name: "bad"}}})
-	if !errors.Is(err, convert.ErrValue) || !strings.Contains(err.Error(), "Batch.Fixed[1]") {
-		t.Fatal(err)
-	}
-	for _, input := range []types.Parent{{Child: &types.Child{Name: "bad"}}, {Children: []*types.Child{nil, {Name: "bad"}}}} {
-		failed, err := mapping.ToParentPtr(input)
-		if failed != nil || !errors.Is(err, convert.ErrValue) || !strings.Contains(err.Error(), "ToChild.Name") {
-			t.Fatal(failed, err)
-		}
-		if len(input.Children) > 0 && !strings.Contains(err.Error(), "ToParent.Children[1]") {
-			t.Fatal(err)
-		}
-		value, err := mapping.ToParent(input)
-		if value.Child != nil || value.Children != nil || !errors.Is(err, convert.ErrValue) {
-			t.Fatal("partial result escaped", err)
-		}
-	}
-}
-
-func TestExplicitNilAndConcurrentCalls(t *testing.T) {
-	zero, err := mapping.ScalarZero(domain.ScalarInput{})
-	if err != nil || zero != (domain.ScalarOutput{}) {
-		t.Fatal(zero, err)
-	}
-	_, err = mapping.ScalarError(domain.ScalarInput{})
-	if err == nil {
-		t.Fatal("nil accepted")
-	}
-	text, count, enabled := "", int64(0), false
-	out, err := mapping.ScalarError(domain.ScalarInput{Text: &text, Count: &count, Enabled: &enabled})
-	if err != nil || out != (domain.ScalarOutput{}) {
-		t.Fatal("non-nil zero rejected", out, err)
-	}
-	var wg sync.WaitGroup
-	for i := 0; i < 32; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			out, err := mapping.ToParent(types.Parent{Child: &types.Child{Name: "parallel"}})
-			if err != nil || out.Child == nil || out.Child.Name != "parallel" {
-				t.Error(out, err)
-			}
-		}()
-	}
-	wg.Wait()
-}
-
-func TestHTTPNullableMapping(t *testing.T) {
-	cfg := logx.Default()
-	cfg.Writer = io.Discard
-	logger, err := logx.New(cfg)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer logger.Close()
-	deps, err := svc.New(context.Background(), logger)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer deps.Close()
-	app, err := handler.NewApp(deps)
-	if err != nil {
-		t.Fatal(err)
-	}
-	defer app.Close()
-	for _, body := range []string{`{}`, `{"child":null}`, `{"child":{"name":""}}`, `{"child":{"name":"one"},"children":[null,{"name":"two"}]}`, `{"children":[]}`} {
-		w := httptest.NewRecorder()
-		req := httptest.NewRequest("POST", "/", strings.NewReader(body))
-		req.Header.Set("Content-Type", "application/json")
-		app.Engine().ServeHTTP(w, req)
-		if w.Code != 200 {
-			t.Fatal(w.Code, w.Body.String())
-		}
-		var input, output types.Parent
-		if err := json.Unmarshal([]byte(body), &input); err != nil {
-			t.Fatal(err)
-		}
-		if err := json.Unmarshal(w.Body.Bytes(), &output); err != nil {
-			t.Fatal(err)
-		}
-		if (input.Child == nil) != (output.Child == nil) || (input.Children == nil) != (output.Children == nil) || len(input.Children) != len(output.Children) {
-			t.Fatal(body, w.Body.String())
-		}
-		if input.Child != nil && input.Child.Name != output.Child.Name {
-			t.Fatal(w.Body.String())
-		}
-	}
-	w := httptest.NewRecorder()
-	req := httptest.NewRequest("POST", "/", strings.NewReader(`{"child":{"name":"bad"}}`))
-	req.Header.Set("Content-Type", "application/json")
-	app.Engine().ServeHTTP(w, req)
-	if w.Code != 500 || strings.Contains(w.Body.String(), convert.ErrValue.Error()) || strings.Contains(w.Body.String(), "ToChild") {
-		t.Fatal("private cause leaked", w.Code, w.Body.String())
-	}
-}
diff --git a/cmd/go-omni/apigen/testdata/nullable/convert.go b/cmd/go-omni/apigen/testdata/nullable/convert.go
deleted file mode 100644
index 6b008cc..0000000
--- a/cmd/go-omni/apigen/testdata/nullable/convert.go
+++ /dev/null
@@ -1,15 +0,0 @@
-package convert
-
-import (
-	"errors"
-	"fmt"
-)
-
-var ErrValue = errors.New("private conversion cause")
-
-func Name(value string) (string, error) {
-	if value == "bad" {
-		return "", fmt.Errorf("conversion refused: %w", ErrValue)
-	}
-	return value, nil
-}
diff --git a/cmd/go-omni/apigen/testdata/nullable/domain.go b/cmd/go-omni/apigen/testdata/nullable/domain.go
deleted file mode 100644
index afb172e..0000000
--- a/cmd/go-omni/apigen/testdata/nullable/domain.go
+++ /dev/null
@@ -1,23 +0,0 @@
-package domain
-
-type Child struct{ Name string }
-type ChildDTO struct{ Name string }
-type Parent struct {
-	Child    *Child
-	Children []*Child
-}
-type Required struct{ Child Child }
-type ValueHolder struct{ Child Child }
-type PointerHolder struct{ Child *ChildDTO }
-type InputBatch struct{ Fixed [2]*Child }
-type OutputBatch struct{ Fixed [2]*ChildDTO }
-type ScalarInput struct {
-	Text    *string
-	Count   *int64
-	Enabled *bool
-}
-type ScalarOutput struct {
-	Text    string
-	Count   int64
-	Enabled bool
-}
diff --git a/cmd/go-omni/apigen/testdata/nullable/service.api b/cmd/go-omni/apigen/testdata/nullable/service.api
deleted file mode 100644
index a41cda3..0000000
--- a/cmd/go-omni/apigen/testdata/nullable/service.api
+++ /dev/null
@@ -1,15 +0,0 @@
-type Child {
-    Name string `json:"name"`
-}
-type Parent {
-    Child *Child `json:"child,optional"`
-    Children []*Child `json:"children,optional"`
-}
-@server (
-    group: probe
-    response: raw
-)
-service probe {
-    @handler roundTrip
-    post / (Parent) returns (Parent)
-}
diff --git a/cmd/go-omni/apigen/write.go b/cmd/go-omni/apigen/write.go
index f273777..1d80e7d 100644
--- a/cmd/go-omni/apigen/write.go
+++ b/cmd/go-omni/apigen/write.go
@@ -117,6 +117,17 @@ func apply(root, module, entry string, generated, seeds map[string][]byte, check
 	var changes []change
 	// Check ALL previous outputs, even stale ones, before writing any new file.
 	for name, hash := range old.Generated {
+		// Migration guard only; old mappings are never regenerated or silently
+		// deleted. Once the project removes them, forget the stale ownership.
+		if name == "internal/mapping/mappingsGen.go" {
+			if err = safePath(root, name); err != nil {
+				return result, err
+			}
+			if _, e := os.Lstat(filepath.Join(root, name)); !errors.Is(e, os.ErrNotExist) {
+				return result, errors.New("mapping generation was removed: migrate callers to copyx or ordinary Go and remove internal/mapping/mappingsGen.go before generating; see COPY.md")
+			}
+			continue
+		}
 		if !ownedPath(name) {
 			return result, fmt.Errorf("api: invalid owned path %q", name)
 		}
@@ -273,9 +284,6 @@ func apply(root, module, entry string, generated, seeds map[string][]byte, check
 }
 func digest(data []byte) string { sum := sha256.Sum256(data); return hex.EncodeToString(sum[:]) }
 func ownedPath(name string) bool {
-	if name == "internal/mapping/mappingsGen.go" {
-		return true
-	}
 	if strings.HasPrefix(name, "internal/types/dto") && strings.HasSuffix(name, "Gen.go") && goName.MatchString(strings.TrimSuffix(filepath.Base(name), ".go")) {
 		return true
 	}
diff --git a/cmd/go-omni/main_test.go b/cmd/go-omni/main_test.go
index 4265713..89848b9 100644
--- a/cmd/go-omni/main_test.go
+++ b/cmd/go-omni/main_test.go
@@ -8,7 +8,7 @@ import (
 )
 
 func TestNewWithRemoteFrameworkVersion(t *testing.T) {
-	for _, flag := range [][]string{{"--framework-version", "v0.18.0-preview"}, {"--framework-version=v0.18.0-preview"}} {
+	for _, flag := range [][]string{{"--framework-version", "v0.19.0-preview"}, {"--framework-version=v0.19.0-preview"}} {
 		project := filepath.Join(t.TempDir(), "billing")
 		args := append([]string{"--module", "example.com/billing"}, flag...)
 		if err := runNew(append(args, project)); err != nil {
@@ -18,7 +18,7 @@ func TestNewWithRemoteFrameworkVersion(t *testing.T) {
 		if err != nil {
 			t.Fatal(err)
 		}
-		if !strings.Contains(string(content), "go-omni v0.18.0-preview") || strings.Contains(string(content), "replace ") {
+		if !strings.Contains(string(content), "go-omni v0.19.0-preview") || strings.Contains(string(content), "replace ") {
 			t.Fatalf("CLI did not pin remote dependency: %s", content)
 		}
 	}
diff --git a/cmd/go-omni/scaffold/version.go b/cmd/go-omni/scaffold/version.go
index 59a5160..45b5802 100644
--- a/cmd/go-omni/scaffold/version.go
+++ b/cmd/go-omni/scaffold/version.go
@@ -10,7 +10,7 @@ const frameworkModule = "git.yuntuo.hk/k2safe/go-omni"
 // Source builds can carry an unpublished VCS version (including +dirty).
 // Keep this fallback in sync with the next release; installed CLIs use their
 // downloaded module version, which also has a module checksum.
-const defaultFrameworkVersion = "v0.18.0-preview"
+const defaultFrameworkVersion = "v0.19.0-preview"
 
 // This target is not a claim that the release already exists. Source users
 // select a local framework checkout until the module templates are published.
diff --git a/copyx/benchmark_test.go b/copyx/benchmark_test.go
new file mode 100644
index 0000000..f82e5f7
--- /dev/null
+++ b/copyx/benchmark_test.go
@@ -0,0 +1,117 @@
+package copyx_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	"git.yuntuo.hk/k2safe/go-omni/copyx"
+)
+
+func BenchmarkScenarios(b *testing.B) {
+	type request struct {
+		Name   string
+		Count  int64
+		Active bool
+	}
+	type result struct {
+		Label  string
+		Count  int64
+		Active bool
+	}
+	source := request{"sample", 9007199254740993, true}
+	option := copyx.WithFieldNames[request, result](map[string]string{"Name": "Label"})
+	copier, err := copyx.New(option)
+	if err != nil {
+		b.Fatal(err)
+	}
+	for _, reuse := range []bool{false, true} {
+		b.Run(fmt.Sprintf("struct/reuse%t", reuse), func(b *testing.B) {
+			b.ReportAllocs()
+			for i := 0; i < b.N; i++ {
+				var target result
+				var err error
+				if reuse {
+					err = copier.Copy(&target, source)
+				} else {
+					err = copyx.Copy(&target, source, option)
+				}
+				if err != nil {
+					b.Fatal(err)
+				}
+			}
+		})
+	}
+	deep, _ := copyx.New(copyx.WithDeepCopy())
+	b.Run("bytes64KiB", func(b *testing.B) {
+		src := make([]byte, 64<<10)
+		b.SetBytes(int64(len(src)))
+		b.ReportAllocs()
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			var dst []byte
+			if err := deep.Copy(&dst, src); err != nil {
+				b.Fatal(err)
+			}
+		}
+	})
+	src := map[string][]int{}
+	for i := 0; i < 100; i++ {
+		src[fmt.Sprint(i)] = []int{1, 2, 3}
+	}
+	b.Run("map100", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			var dst map[string][]int
+			if err := deep.Copy(&dst, src); err != nil {
+				b.Fatal(err)
+			}
+		}
+	})
+	cycle := &detail{Values: []int{1, 2, 3}}
+	cycle.Next = cycle
+	b.Run("cycle", func(b *testing.B) {
+		b.ReportAllocs()
+		for i := 0; i < b.N; i++ {
+			var dst *detail
+			if err := deep.Copy(&dst, cycle); err != nil {
+				b.Fatal(err)
+			}
+		}
+	})
+	b.Run("parallelCycle", func(b *testing.B) {
+		b.ReportAllocs()
+		b.RunParallel(func(pb *testing.PB) {
+			for pb.Next() {
+				var dst *detail
+				if err := deep.Copy(&dst, cycle); err != nil {
+					b.Error(err)
+					return
+				}
+			}
+		})
+	})
+	for _, fresh := range []bool{false, true} {
+		b.Run(fmt.Sprintf("converter/fresh%t", fresh), func(b *testing.B) {
+			c, err := copyx.New(copyx.WithDeepCopy(), copyx.WithConverter(func(v []int) ([]int, error) {
+				if fresh {
+					return append([]int(nil), v...), nil
+				}
+				return v, nil
+			}))
+			if err != nil {
+				b.Fatal(err)
+			}
+			src := []int{1, 2, 3}
+			b.ReportAllocs()
+			b.ResetTimer()
+			for i := 0; i < b.N; i++ {
+				var dst []int
+				err := c.Copy(&dst, src)
+				if fresh && err != nil || !fresh && !errors.Is(err, copyx.ErrSharedReference) {
+					b.Fatal(err)
+				}
+			}
+		})
+	}
+}
diff --git a/copyx/copy.go b/copyx/copy.go
new file mode 100644
index 0000000..97417d3
--- /dev/null
+++ b/copyx/copy.go
@@ -0,0 +1,537 @@
+package copyx
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"runtime"
+	"sort"
+	"sync"
+)
+
+var (
+	ErrType            = errors.New("copyx: incompatible types")
+	ErrNil             = errors.New("copyx: nil cannot fill a non-nullable target")
+	ErrField           = errors.New("copyx: unmatched field")
+	ErrUnsupported     = errors.New("copyx: unsupported value; provide an explicit data converter")
+	ErrSharedReference = errors.New("copyx: deep copy retains a mutable source reference")
+	ErrLimit           = errors.New("copyx: traversal limit exceeded")
+)
+
+// Error describes a field/index path without recording the source value.
+type Error struct {
+	Path  string
+	Cause error
+}
+
+func (e *Error) Error() string        { return e.Path + ": " + e.Cause.Error() }
+func (e *Error) Unwrap() error        { return e.Cause }
+func at(path string, err error) error { return &Error{Path: path, Cause: err} }
+
+func Copy(target, source any, options ...Option) error {
+	c, err := New(options...)
+	if err != nil {
+		return err
+	}
+	return c.Copy(target, source)
+}
+
+// Clone always makes a deep copy. Nil and empty collections stay distinct.
+func Clone[T any](source T, options ...Option) (T, error) {
+	var target T
+	options = append(append([]Option(nil), options...), WithDeepCopy())
+	err := Copy(&target, source, options...)
+	return target, err
+}
+
+// Copy stages the complete result and only assigns target on success. User
+// converter side effects (including mutation of source) cannot be rolled back.
+// Caller must synchronize concurrent access to source and target themselves.
+func (c *Copier) Copy(target, source any) error {
+	// Alias indexes contain addresses only. Keep the original graph alive until
+	// validation and commit finish so the GC cannot recycle any indexed address.
+	defer func() { runtime.KeepAlive(source) }()
+	if c == nil {
+		return errors.New("copyx: nil Copier")
+	}
+	dst := reflect.ValueOf(target)
+	if !dst.IsValid() || dst.Kind() != reflect.Pointer || dst.IsNil() {
+		return errors.New("copyx: target must be a non-nil pointer")
+	}
+	src := reflect.ValueOf(source)
+	s := state{options: &c.options, seen: map[visit]reflect.Value{}}
+	if c.options.deep {
+		var err error
+		s.graph, err = sourceGraph(src)
+		if err != nil {
+			return err
+		}
+		if src.IsValid() && src.Kind() == reflect.Pointer && !src.IsNil() && dst.Elem().Kind() == reflect.Struct {
+			id := identity(src)
+			s.valueRoot = &id
+		}
+	}
+	out, err := s.walk(src, dst.Elem(), dst.Elem().Type(), "$", 0)
+	if err != nil {
+		return err
+	}
+	if s.graph != nil {
+		if err = s.graph.audit(out); err != nil {
+			return err
+		}
+	}
+	dst.Elem().Set(out)
+	return nil
+}
+
+type visit struct {
+	reference
+	target reflect.Type
+}
+type state struct {
+	options   *settings
+	seen      map[visit]reflect.Value
+	graph     *graph
+	nodes     int
+	allocated uint64
+	valueRoot *reference
+}
+
+func (s *state) reserve(count int, size uintptr, path string) error {
+	if count < 0 || (count > 0 && uint64(size) > maxCopyBytes/uint64(count)) {
+		return at(path, ErrLimit)
+	}
+	s.allocated += uint64(count) * uint64(size)
+	if s.allocated > maxCopyBytes {
+		return at(path, ErrLimit)
+	}
+	return nil
+}
+
+func nullable(k reflect.Kind) bool {
+	switch k {
+	case reflect.Pointer, reflect.Map, reflect.Slice, reflect.Interface, reflect.Func, reflect.Chan:
+		return true
+	}
+	return false
+}
+func baseValue(base reflect.Value, t reflect.Type) reflect.Value {
+	if base.IsValid() && base.Type() == t {
+		return base
+	}
+	return reflect.Zero(t)
+}
+func (s *state) walk(src, base reflect.Value, t reflect.Type, path string, depth int) (reflect.Value, error) {
+	s.nodes++
+	if depth > maxDepth || s.nodes > maxNodes {
+		return reflect.Value{}, at(path, ErrLimit)
+	}
+	base = baseValue(base, t)
+	if !shallowSafe(t) {
+		return reflect.Value{}, at(path, ErrUnsupported)
+	}
+	if src.IsValid() && !src.CanInterface() {
+		return reflect.Value{}, at(path, ErrUnsupported)
+	}
+	// Exact converters also receive typed nils and zeros. No method calls,
+	// Scanner/Valuer invocation or implicit numeric conversion is attempted.
+	if src.IsValid() {
+		if convert, ok := s.options.converters[pair{src.Type(), t}]; ok {
+			out, err := convert(src)
+			if err != nil {
+				return reflect.Value{}, at(path, err)
+			}
+			if s.graph != nil {
+				if err = s.graph.audit(out); err != nil {
+					return reflect.Value{}, at(path, err)
+				}
+			}
+			return out, nil
+		}
+	}
+	if !src.IsValid() || (nullable(src.Kind()) && src.IsNil()) {
+		if src.IsValid() && !s.nilCompatible(src.Type(), t, map[pair]bool{}) {
+			return reflect.Value{}, at(path, ErrType)
+		}
+		if s.options.nilPolicy == NilSkip {
+			return base, nil
+		}
+		if nullable(t.Kind()) || s.options.nilPolicy == NilZero {
+			return reflect.Zero(t), nil
+		}
+		return reflect.Value{}, at(path, ErrNil)
+	}
+	if s.options.skipZero && src.IsZero() {
+		if !s.nilCompatible(src.Type(), t, map[pair]bool{}) {
+			return reflect.Value{}, at(path, ErrType)
+		}
+		return base, nil
+	}
+	if src.Type() == t && len(s.options.converters) == 0 && len(s.options.fields) == 0 && !s.options.skipZero && s.options.nilPolicy != NilSkip {
+		if !s.options.deep || simpleValue(t) {
+			return src, nil
+		}
+	}
+	if src.Kind() == reflect.Interface {
+		return s.walk(src.Elem(), base, t, path, depth+1)
+	}
+	if t.Kind() == reflect.Interface {
+		if !src.Type().Implements(t) {
+			return reflect.Value{}, at(path, ErrType)
+		}
+		out, err := s.walk(src, reflect.Value{}, src.Type(), path, depth+1)
+		if err != nil {
+			return reflect.Value{}, err
+		}
+		v := reflect.New(t).Elem()
+		v.Set(out)
+		return v, nil
+	}
+	if s.options.deep && forbidden(t) {
+		return reflect.Value{}, at(path, ErrUnsupported)
+	}
+	if src.Kind() == reflect.Pointer && t.Kind() != reflect.Pointer {
+		return s.walk(src.Elem(), base, t, path, depth+1)
+	}
+	if t.Kind() == reflect.Pointer {
+		if !s.options.deep && src.Type() == t {
+			return src, nil
+		}
+		if src.Kind() == reflect.Pointer {
+			key := visit{identity(src), t}
+			if s.valueRoot != nil && key.reference == *s.valueRoot {
+				return reflect.Value{}, at(path, fmt.Errorf("%w: cyclic root must retain its pointer; use Clone(source) or Copy(&targetPointer, source)", ErrUnsupported))
+			}
+			if prior, ok := s.seen[key]; ok {
+				return prior, nil
+			}
+		}
+		if err := s.reserve(1, t.Elem().Size(), path); err != nil {
+			return reflect.Value{}, err
+		}
+		out := reflect.New(t.Elem())
+		if out.Type() != t {
+			out = out.Convert(t)
+		}
+		if src.Kind() == reflect.Pointer {
+			key := visit{identity(src), t}
+			s.seen[key] = out
+			src = src.Elem()
+		}
+		var childBase reflect.Value
+		if !base.IsNil() {
+			childBase = base.Elem()
+		}
+		value, err := s.walk(src, childBase, t.Elem(), path, depth+1)
+		if err != nil {
+			return reflect.Value{}, err
+		}
+		out.Elem().Set(value)
+		return out, nil
+	}
+	if src.Kind() != t.Kind() {
+		return reflect.Value{}, at(path, fmt.Errorf("%w: %s -> %s", ErrType, src.Type(), t))
+	}
+	if t == timeType && src.Type() == t {
+		return src, nil
+	}
+	switch t.Kind() {
+	case reflect.Struct:
+		return s.structure(src, base, t, path, depth)
+	case reflect.Slice:
+		if !s.options.deep && src.Type() == t {
+			return src, nil
+		}
+		key := visit{identity(src), t}
+		if prior, ok := s.seen[key]; ok {
+			return prior, nil
+		}
+		if err := s.reserve(src.Len(), t.Elem().Size(), path); err != nil {
+			return reflect.Value{}, err
+		}
+		out := reflect.MakeSlice(t, src.Len(), src.Len())
+		s.seen[key] = out
+		if src.Type() == t && len(s.options.converters) == 0 && len(s.options.fields) == 0 && simpleValue(t.Elem()) {
+			reflect.Copy(out, src)
+			return out, nil
+		}
+		for i := 0; i < src.Len(); i++ {
+			v, err := s.walk(src.Index(i), reflect.Value{}, t.Elem(), fmt.Sprintf("%s[%d]", path, i), depth+1)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			out.Index(i).Set(v)
+		}
+		return out, nil
+	case reflect.Array:
+		if src.Len() != t.Len() {
+			return reflect.Value{}, at(path, ErrType)
+		}
+		if err := s.reserve(1, t.Size(), path); err != nil {
+			return reflect.Value{}, err
+		}
+		out := reflect.New(t).Elem()
+		for i := 0; i < src.Len(); i++ {
+			v, err := s.walk(src.Index(i), base.Index(i), t.Elem(), fmt.Sprintf("%s[%d]", path, i), depth+1)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			out.Index(i).Set(v)
+		}
+		return out, nil
+	case reflect.Map:
+		if !s.options.deep && src.Type() == t {
+			return src, nil
+		}
+		key := visit{identity(src), t}
+		if prior, ok := s.seen[key]; ok {
+			return prior, nil
+		}
+		if err := s.reserve(src.Len(), t.Key().Size()+t.Elem().Size()+32, path); err != nil {
+			return reflect.Value{}, err
+		}
+		out := reflect.MakeMapWithSize(t, src.Len())
+		s.seen[key] = out
+		it := src.MapRange()
+		for it.Next() {
+			k, err := s.walk(it.Key(), reflect.Value{}, t.Key(), path+"[key]", depth+1)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			if !k.Comparable() {
+				return reflect.Value{}, at(path+"[key]", ErrType)
+			}
+			if out.MapIndex(k).IsValid() {
+				return reflect.Value{}, at(path+"[key]", errors.New("copyx: key conversion collision"))
+			}
+			v, err := s.walk(it.Value(), reflect.Value{}, t.Elem(), path+"[value]", depth+1)
+			if err != nil {
+				return reflect.Value{}, err
+			}
+			out.SetMapIndex(k, v)
+		}
+		return out, nil
+	case reflect.Func, reflect.Chan, reflect.UnsafePointer:
+		if s.options.deep {
+			return reflect.Value{}, at(path, ErrUnsupported)
+		}
+	}
+	if src.Type() != t {
+		return reflect.Value{}, at(path, fmt.Errorf("%w: %s -> %s", ErrType, src.Type(), t))
+	}
+	return src, nil
+}
+
+var fieldTypes sync.Map
+
+func exportedFields(t reflect.Type) map[string]reflect.StructField {
+	if known, ok := fieldTypes.Load(t); ok {
+		return known.(map[string]reflect.StructField)
+	}
+	out := map[string]reflect.StructField{}
+	for _, f := range reflect.VisibleFields(t) {
+		if f.PkgPath != "" {
+			continue
+		}
+		kind := f.Type.Kind()
+		if kind == reflect.Pointer {
+			kind = f.Type.Elem().Kind()
+		}
+		if f.Anonymous && kind == reflect.Struct {
+			continue
+		}
+		out[f.Name] = f
+	}
+	actual, _ := fieldTypes.LoadOrStore(t, out)
+	return actual.(map[string]reflect.StructField)
+}
+
+func (s *state) nilCompatible(from, to reflect.Type, seen map[pair]bool) bool {
+	key := pair{from, to}
+	if seen[key] {
+		return true
+	}
+	seen[key] = true
+	if from == to {
+		return true
+	}
+	if _, ok := s.options.converters[key]; ok {
+		return true
+	}
+	if to.Kind() == reflect.Interface {
+		return from.Implements(to)
+	}
+	if from.Kind() == reflect.Pointer {
+		return s.nilCompatible(from.Elem(), to, seen)
+	}
+	if to.Kind() == reflect.Pointer {
+		return s.nilCompatible(from, to.Elem(), seen)
+	}
+	if from.Kind() != to.Kind() {
+		return false
+	}
+	switch from.Kind() {
+	case reflect.Struct:
+		// Nil must not hide a structurally incompatible type pair. There are no
+		// field values to visit, but coverage and conversion types still apply.
+		for i := 0; i < to.NumField(); i++ {
+			if to.Field(i).PkgPath != "" {
+				return false
+			}
+		}
+		sources, targets := exportedFields(from), exportedFields(to)
+		rules := s.options.fields[key]
+		if rules == nil {
+			rules = &fields{}
+		}
+		reverse, used := map[string]string{}, map[string]bool{}
+		for a, b := range rules.names {
+			reverse[b] = a
+		}
+		for name, target := range targets {
+			if rules.ignoreTarget[name] {
+				continue
+			}
+			srcName := name
+			if renamed, ok := reverse[name]; ok {
+				srcName = renamed
+			}
+			source, ok := sources[srcName]
+			if !ok || rules.ignoreSource[srcName] || !s.nilCompatible(source.Type, target.Type, seen) {
+				return false
+			}
+			used[srcName] = true
+		}
+		if s.options.strict {
+			for name := range sources {
+				if !used[name] && !rules.ignoreSource[name] {
+					return false
+				}
+			}
+		}
+		return true
+	case reflect.Slice:
+		return s.nilCompatible(from.Elem(), to.Elem(), seen)
+	case reflect.Map:
+		return s.nilCompatible(from.Key(), to.Key(), seen) && s.nilCompatible(from.Elem(), to.Elem(), seen)
+	case reflect.Array:
+		return from.Len() == to.Len() && s.nilCompatible(from.Elem(), to.Elem(), seen)
+	}
+	return false
+}
+func fieldValue(v reflect.Value, index []int) (reflect.Value, bool) {
+	for _, i := range index {
+		if v.Kind() == reflect.Pointer {
+			if v.IsNil() {
+				return reflect.Value{}, false
+			}
+			v = v.Elem()
+		}
+		v = v.Field(i)
+	}
+	return v, true
+}
+func setField(v reflect.Value, index []int, value reflect.Value) error {
+	for j, i := range index {
+		field := v.Field(i)
+		if !field.CanSet() {
+			return ErrUnsupported
+		}
+		if j == len(index)-1 {
+			field.Set(value)
+			return nil
+		}
+		if field.Kind() == reflect.Pointer {
+			// Detach embedded destination pointers before editing promoted fields.
+			fresh := reflect.New(field.Type().Elem())
+			if !field.IsNil() {
+				fresh.Elem().Set(field.Elem())
+			}
+			field.Set(fresh)
+			v = fresh.Elem()
+		} else {
+			v = field
+		}
+	}
+	return nil
+}
+func (s *state) structure(src, base reflect.Value, t reflect.Type, path string, depth int) (reflect.Value, error) {
+	if err := s.reserve(1, t.Size(), path); err != nil {
+		return reflect.Value{}, err
+	}
+	out := reflect.New(t).Elem()
+	out.Set(base)
+	if src.Type() == t {
+		// Private scalar state may be assigned as part of its whole value; mutable
+		// private state requires a converter, never unsafe writes or silent loss.
+		for i := 0; i < t.NumField(); i++ {
+			f := t.Field(i)
+			if f.PkgPath != "" && s.options.deep && privateMutable(f.Type) {
+				return reflect.Value{}, at(path+"."+f.Name, ErrUnsupported)
+			}
+		}
+		out.Set(src)
+	} else {
+		for i := 0; i < t.NumField(); i++ {
+			if t.Field(i).PkgPath != "" {
+				return reflect.Value{}, at(path, ErrUnsupported)
+			}
+		}
+	}
+	from, to := exportedFields(src.Type()), exportedFields(t)
+	rules := s.options.fields[pair{src.Type(), t}]
+	if rules == nil {
+		rules = &fields{map[string]string{}, map[string]bool{}, map[string]bool{}}
+	}
+	reverse := map[string]string{}
+	for a, b := range rules.names {
+		reverse[b] = a
+	}
+	names := make([]string, 0, len(to))
+	for n := range to {
+		names = append(names, n)
+	}
+	sort.Strings(names)
+	used := map[string]bool{}
+	for _, name := range names {
+		target := to[name]
+		old, _ := fieldValue(base, target.Index)
+		if rules.ignoreTarget[name] {
+			if !old.IsValid() {
+				old = reflect.Zero(target.Type)
+			}
+			if err := setField(out, target.Index, old); err != nil {
+				return reflect.Value{}, at(path+"."+name, err)
+			}
+			continue
+		}
+		srcName := name
+		if renamed, ok := reverse[name]; ok {
+			srcName = renamed
+		}
+		source, ok := from[srcName]
+		if !ok || rules.ignoreSource[srcName] {
+			return reflect.Value{}, at(path+"."+name, ErrField)
+		}
+		used[srcName] = true
+		v, ok := fieldValue(src, source.Index)
+		if !ok {
+			return reflect.Value{}, at(path+"."+name, ErrNil)
+		}
+		value, err := s.walk(v, old, target.Type, path+"."+name, depth+1)
+		if err != nil {
+			return reflect.Value{}, err
+		}
+		if err = setField(out, target.Index, value); err != nil {
+			return reflect.Value{}, at(path+"."+name, err)
+		}
+	}
+	if s.options.strict {
+		for name := range from {
+			if !used[name] && !rules.ignoreSource[name] {
+				return reflect.Value{}, at(path+"."+name, ErrField)
+			}
+		}
+	}
+	return out, nil
+}
diff --git a/copyx/copy_test.go b/copyx/copy_test.go
new file mode 100644
index 0000000..8ba9904
--- /dev/null
+++ b/copyx/copy_test.go
@@ -0,0 +1,448 @@
+package copyx_test
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"git.yuntuo.hk/k2safe/go-omni/copyx"
+)
+
+type detail struct {
+	Values []int
+	Index  map[string][]int
+	Next   *detail
+}
+
+func TestDeepGraph(t *testing.T) {
+	src := &detail{Values: []int{1, 2}, Index: map[string][]int{"a": {3}}}
+	src.Next = src
+	dst, err := copyx.Clone(src)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if dst == src || dst.Next != dst {
+		t.Fatal("pointer cycle not preserved")
+	}
+	dst.Values[0] = 9
+	dst.Index["a"][0] = 8
+	if src.Values[0] != 1 || src.Index["a"][0] != 3 {
+		t.Fatal("deep alias")
+	}
+	m := map[string]any{}
+	m["self"] = m
+	n, err := copyx.Clone(m)
+	if err != nil {
+		t.Fatal(err)
+	}
+	n["self"].(map[string]any)["new"] = 1
+	if n["new"] != 1 || m["new"] != nil {
+		t.Fatal("map cycle changed")
+	}
+	x := []any{nil}
+	x[0] = x
+	y, err := copyx.Clone(x)
+	if err != nil {
+		t.Fatal(err)
+	}
+	y[0].([]any)[0] = "changed"
+	if y[0] != "changed" {
+		t.Fatal("slice cycle changed")
+	}
+	if _, ok := x[0].([]any); !ok {
+		t.Fatal("source slice changed")
+	}
+}
+func TestShallowAndNil(t *testing.T) {
+	src := detail{Values: []int{1}}
+	var dst detail
+	if err := copyx.Copy(&dst, src); err != nil {
+		t.Fatal(err)
+	}
+	dst.Values[0] = 2
+	if src.Values[0] != 2 {
+		t.Fatal("shallow unexpectedly detached")
+	}
+	for _, slice := range [][]int{nil, {}} {
+		out, err := copyx.Clone(slice)
+		if err != nil || (out == nil) != (slice == nil) {
+			t.Fatal(out, err)
+		}
+	}
+	for _, m := range []map[string]int{nil, {}} {
+		out, err := copyx.Clone(m)
+		if err != nil || (out == nil) != (m == nil) {
+			t.Fatal(out, err)
+		}
+	}
+	var p *int
+	n := 7
+	if err := copyx.Copy(&n, p); !errors.Is(err, copyx.ErrNil) || n != 7 {
+		t.Fatal(n, err)
+	}
+	if err := copyx.Copy(&n, p, copyx.WithNilPolicy(copyx.NilSkip)); err != nil || n != 7 {
+		t.Fatal(n, err)
+	}
+	if err := copyx.Copy(&n, p, copyx.WithNilPolicy(copyx.NilZero)); err != nil || n != 0 {
+		t.Fatal(n, err)
+	}
+	x := 3
+	out := &x
+	if err := copyx.Copy(&out, p); err != nil || out != nil {
+		t.Fatal(out, err)
+	}
+	flag := true
+	if err := copyx.Copy(&flag, false); err != nil || flag {
+		t.Fatal(flag, err)
+	}
+	flag = true
+	if err := copyx.Copy(&flag, false, copyx.WithSkipZero()); err != nil || !flag {
+		t.Fatal(flag, err)
+	}
+}
+
+func TestConverterAliasesRejected(t *testing.T) {
+	for _, kind := range []string{"same", "nested", "subslice", "capacity", "fieldPointer", "private", "map", "sibling"} {
+		t.Run(kind, func(t *testing.T) {
+			src := &detail{Values: []int{1, 2, 3}, Index: map[string][]int{"x": {1}}}
+			var err error
+			switch kind {
+			case "same":
+				_, err = copyx.Clone(src, copyx.WithConverter(func(v *detail) (*detail, error) { return v, nil }))
+			case "nested":
+				_, err = copyx.Clone(src, copyx.WithConverter(func(v *detail) (*detail, error) { return &detail{Values: v.Values}, nil }))
+			case "subslice":
+				_, err = copyx.Clone(src.Values, copyx.WithConverter(func(v []int) ([]int, error) { return v[1:], nil }))
+			case "capacity":
+				_, err = copyx.Clone(src.Values, copyx.WithConverter(func(v []int) ([]int, error) { return v[:0], nil }))
+			case "map":
+				_, err = copyx.Clone(src.Index, copyx.WithConverter(func(v map[string][]int) (map[string][]int, error) { return v, nil }))
+			case "fieldPointer":
+				var dst *int
+				err = copyx.Copy(&dst, src.Values, copyx.WithDeepCopy(), copyx.WithConverter(func(v []int) (*int, error) { return &v[1], nil }))
+			case "private":
+				type opaque struct{ data []int }
+				v := opaque{src.Values}
+				_, err = copyx.Clone(v, copyx.WithConverter(func(v opaque) (opaque, error) { return v, nil }))
+			case "sibling":
+				type object struct{ A, B []int }
+				v := object{[]int{1}, []int{2}}
+				_, err = copyx.Clone(v, copyx.WithConverter(func(_ []int) ([]int, error) { return v.B, nil }))
+			}
+			if !errors.Is(err, copyx.ErrSharedReference) {
+				t.Fatalf("got %v", err)
+			}
+		})
+	}
+	_, err := copyx.Clone(4, copyx.WithConverter(func(v int) (int, error) { return v, nil }))
+	if err != nil {
+		t.Fatal("equal primitive rejected", err)
+	}
+	_, err = copyx.Clone("same", copyx.WithConverter(func(v string) (string, error) { return v, nil }))
+	if err != nil {
+		t.Fatal(err)
+	}
+	good, err := copyx.Clone([]int{1}, copyx.WithConverter(func(v []int) ([]int, error) { return append([]int(nil), v...), nil }))
+	if err != nil || good[0] != 1 {
+		t.Fatal(good, err)
+	}
+}
+
+func TestPrivateAndUnsupported(t *testing.T) {
+	type money struct{ cents *int64 }
+	n := int64(9007199254740991)
+	src := money{&n}
+	if _, err := copyx.Clone(src); !errors.Is(err, copyx.ErrUnsupported) {
+		t.Fatal(err)
+	}
+	out, err := copyx.Clone(src, copyx.WithConverter(func(v money) (money, error) { n := *v.cents; return money{&n}, nil }))
+	if err != nil || *out.cents != n || out.cents == src.cents {
+		t.Fatal(out, err)
+	}
+	tm := time.Now()
+	cloned, err := copyx.Clone(tm)
+	if err != nil || !cloned.Equal(tm) {
+		t.Fatal(cloned, err)
+	}
+	for _, v := range []any{make(chan int), func() {}, &sync.Mutex{}, sync.Mutex{}} {
+		if _, err := copyx.Clone(v); !errors.Is(err, copyx.ErrUnsupported) {
+			t.Fatalf("%T: %v", v, err)
+		}
+	}
+}
+
+func TestNilTypeMismatchAndInterfaceConverter(t *testing.T) {
+	var source *string
+	target := 7
+	if err := copyx.Copy(&target, source, copyx.WithNilPolicy(copyx.NilZero)); !errors.Is(err, copyx.ErrType) || target != 7 {
+		t.Fatal(target, err)
+	}
+	var list []int
+	var targetMap map[string]int
+	if err := copyx.Copy(&targetMap, list); !errors.Is(err, copyx.ErrType) {
+		t.Fatal(err)
+	}
+	type input struct{ Value any }
+	type output struct{ Value string }
+	var out output
+	err := copyx.Copy(&out, input{}, copyx.WithConverter(func(v any) (string, error) {
+		if v == nil {
+			return "nil handled", nil
+		}
+		return "value", nil
+	}))
+	if err != nil || out.Value != "nil handled" {
+		t.Fatal(out, err)
+	}
+	var lock sync.Mutex
+	if err := copyx.Copy(&lock, sync.Mutex{}); !errors.Is(err, copyx.ErrUnsupported) {
+		t.Fatal(err)
+	}
+	type locked struct {
+		mu    sync.Mutex
+		Value int
+	}
+	var l locked
+	if err := copyx.Copy(&l, locked{}); !errors.Is(err, copyx.ErrUnsupported) {
+		t.Fatal(err)
+	}
+}
+
+func TestAllocationLimitAndPointerRoot(t *testing.T) {
+	src := make([]byte, (64<<20)+1)
+	if _, err := copyx.Clone(src); !errors.Is(err, copyx.ErrLimit) {
+		t.Fatal(err)
+	}
+	n := &detail{}
+	n.Next = n
+	var value detail
+	if err := copyx.Copy(&value, n, copyx.WithDeepCopy()); !errors.Is(err, copyx.ErrUnsupported) {
+		t.Fatal(err)
+	}
+	var p *detail
+	if err := copyx.Copy(&p, n, copyx.WithDeepCopy()); err != nil || p.Next != p || p == n {
+		t.Fatal(p, err)
+	}
+}
+func TestFieldsConvertersAndAtomicity(t *testing.T) {
+	type input struct {
+		Name  string
+		Age   int
+		Extra string
+	}
+	type output struct {
+		Label string
+		Age   int
+		Local string
+	}
+	rename := map[string]string{"Name": "Label"}
+	c, err := copyx.New(copyx.WithFieldNames[input, output](rename), copyx.WithIgnoreTarget[input, output]("Local"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	rename["Name"] = "Missing"
+	dst := output{Local: "preserved"}
+	if err = c.Copy(&dst, input{Name: "hello", Age: 2}); err != nil || dst.Label != "hello" || dst.Local != "preserved" {
+		t.Fatal(dst, err)
+	}
+	if err = copyx.Copy(&dst, input{}, copyx.WithStrictFields(), copyx.WithFieldNames[input, output](map[string]string{"Name": "Label"}), copyx.WithIgnoreTarget[input, output]("Local")); !errors.Is(err, copyx.ErrField) {
+		t.Fatal(err)
+	}
+	if err = copyx.Copy(&dst, input{}, copyx.WithStrictFields(), copyx.WithFieldNames[input, output](map[string]string{"Name": "Label"}), copyx.WithIgnoreTarget[input, output]("Local"), copyx.WithIgnoreSource[input, output]("Extra")); err != nil {
+		t.Fatal(err)
+	}
+	if err = copyx.Copy(&dst, input{}); !errors.Is(err, copyx.ErrField) {
+		t.Fatal(err)
+	}
+	if _, err = copyx.New(copyx.WithFieldNames[input, output](map[string]string{"Nope": "Age"})); err == nil {
+		t.Fatal("invalid rule accepted")
+	}
+	if _, err = copyx.New(copyx.WithConverter(func(v int) (string, error) { return "", nil }), copyx.WithConverter(func(v int) (string, error) { return "", nil })); err == nil {
+		t.Fatal("duplicate converter accepted")
+	}
+
+	sentinel := errors.New("conversion failed")
+	type node struct {
+		A []int
+		Z string
+	}
+	old := node{[]int{8}, "old"}
+	before := old.A
+	err = copyx.Copy(&old, node{[]int{1}, "bad"}, copyx.WithDeepCopy(), copyx.WithConverter(func(v string) (string, error) { return "", sentinel }))
+	if !errors.Is(err, sentinel) || !strings.Contains(err.Error(), "Z") || old.Z != "old" || old.A[0] != 8 || &old.A[0] != &before[0] {
+		t.Fatal(old, err)
+	}
+	// Exact typed nil converter must get control before the global nil policy.
+	var ptr *int
+	var value int
+	err = copyx.Copy(&value, ptr, copyx.WithConverter(func(v *int) (int, error) {
+		if v == nil {
+			return 0, sentinel
+		}
+		return *v, nil
+	}))
+	if !errors.Is(err, sentinel) {
+		t.Fatal(err)
+	}
+	var small int8 = 3
+	if err = copyx.Copy(&small, int64(300)); !errors.Is(err, copyx.ErrType) || small != 3 {
+		t.Fatal(small, err)
+	}
+}
+
+type Embedded struct {
+	A int
+	Z string
+}
+
+func TestEmbeddedDestinationDetached(t *testing.T) {
+	type target struct{ *Embedded }
+	type source struct {
+		A int
+		Z int
+	}
+	ptr := &Embedded{5, "keep"}
+	dst := target{ptr}
+	if err := copyx.Copy(&dst, source{6, 7}); !errors.Is(err, copyx.ErrType) {
+		t.Fatal(err)
+	}
+	if ptr.A != 5 || dst.Embedded != ptr {
+		t.Fatal("failure mutated embedded target")
+	}
+	if err := copyx.Copy(&dst, Embedded{6, "new"}); err != nil {
+		t.Fatal(err)
+	}
+	if ptr.A != 5 || dst.A != 6 {
+		t.Fatal("success mutated old embedded object")
+	}
+}
+func TestConcurrentCopier(t *testing.T) {
+	c, err := copyx.New(copyx.WithDeepCopy())
+	if err != nil {
+		t.Fatal(err)
+	}
+	src := &detail{Values: []int{7}, Index: map[string][]int{"a": {9}}}
+	var wg sync.WaitGroup
+	for i := 0; i < 64; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			for n := 0; n < 20; n++ {
+				var dst *detail
+				if err := c.Copy(&dst, src); err != nil {
+					t.Error(err)
+					return
+				}
+				dst.Values[0] = n
+				if src.Values[0] != 7 {
+					t.Error("shared")
+				}
+			}
+		}()
+	}
+	wg.Wait()
+}
+func TestBoundAndCollections(t *testing.T) {
+	src := &detail{}
+	p := src
+	for i := 0; i < 300; i++ {
+		p.Next = &detail{}
+		p = p.Next
+	}
+	if _, err := copyx.Clone(src); !errors.Is(err, copyx.ErrLimit) {
+		t.Fatal(err)
+	}
+	type from struct{ Value string }
+	type to struct{ Value string }
+	var out []to
+	if err := copyx.Copy(&out, []from{{"a"}, {"b"}}); err != nil || len(out) != 2 || out[1].Value != "b" {
+		t.Fatal(out, err)
+	}
+	var array [2]to
+	if err := copyx.Copy(&array, [2]from{{"a"}, {"b"}}); err != nil {
+		t.Fatal(err)
+	}
+	if err := copyx.Copy(&array, [1]from{{"a"}}); !errors.Is(err, copyx.ErrType) {
+		t.Fatal(err)
+	}
+	var outMap map[string]int
+	err := copyx.Copy(&outMap, map[int]int{1: 1, 2: 2}, copyx.WithConverter(func(int) (string, error) { return "same", nil }))
+	if err == nil || outMap != nil {
+		t.Fatal(outMap, err)
+	}
+}
+func FuzzClone(f *testing.F) {
+	f.Add([]byte{1, 2, 3})
+	f.Add([]byte{})
+	f.Fuzz(func(t *testing.T, data []byte) {
+		if len(data) > 1024 {
+			data = data[:1024]
+		}
+		src := map[string]any{"bytes": data, "other": []string{"x"}}
+		out, err := copyx.Clone(src)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if !reflect.DeepEqual(src, out) {
+			t.Fatal("changed value")
+		}
+		if len(data) > 0 {
+			out["bytes"].([]byte)[0] ^= 255
+			if data[0] == out["bytes"].([]byte)[0] {
+				t.Fatal("alias")
+			}
+		}
+	})
+}
+
+func TestTraversalNodeLimit(t *testing.T) {
+	source := make([]any, 200001)
+	if _, err := copyx.Clone(source); !errors.Is(err, copyx.ErrLimit) {
+		t.Fatal("expected bounded traversal", err)
+	}
+}
+
+func TestNilCannotHideFieldMismatch(t *testing.T) {
+	type source struct{ Value string }
+	type target struct{ Value int }
+	var src *source
+	var dst *target
+	for _, policy := range []copyx.NilPolicy{copyx.NilError, copyx.NilZero, copyx.NilSkip} {
+		if err := copyx.Copy(&dst, src, copyx.WithNilPolicy(policy)); !errors.Is(err, copyx.ErrType) {
+			t.Fatal("nil concealed incompatible fields", err)
+		}
+	}
+	if err := copyx.Copy(&dst, src, copyx.WithConverter(func(string) (int, error) { return 0, nil })); err != nil {
+		t.Fatal(err)
+	}
+	text := "keep"
+	if err := copyx.Copy(&text, 0, copyx.WithSkipZero()); !errors.Is(err, copyx.ErrType) || text != "keep" {
+		t.Fatal("zero concealed incompatible types", text, err)
+	}
+}
+func BenchmarkCopy(b *testing.B) {
+	for _, n := range []int{1, 100, 1000} {
+		for _, deep := range []bool{false, true} {
+			b.Run(fmt.Sprintf("fields%d/deep%t", n, deep), func(b *testing.B) {
+				src := detail{Values: make([]int, n), Index: map[string][]int{"one": {1, 2}}}
+				var opts []copyx.Option
+				if deep {
+					opts = append(opts, copyx.WithDeepCopy())
+				}
+				c, _ := copyx.New(opts...)
+				b.ReportAllocs()
+				b.ResetTimer()
+				for i := 0; i < b.N; i++ {
+					var dst detail
+					if err := c.Copy(&dst, src); err != nil {
+						b.Fatal(err)
+					}
+				}
+			})
+		}
+	}
+}
diff --git a/copyx/graph.go b/copyx/graph.go
new file mode 100644
index 0000000..a1f33e4
--- /dev/null
+++ b/copyx/graph.go
@@ -0,0 +1,270 @@
+package copyx
+
+import (
+	"fmt"
+	"reflect"
+	"sort"
+	"sync"
+	"time"
+)
+
+const maxDepth = 256
+const maxNodes = 200000
+const maxCopyBytes = 64 << 20
+
+var timeType = reflect.TypeFor[time.Time]()
+
+// Immutable type metadata is shared, never values or converter registrations.
+var valueTypes sync.Map
+
+func simpleValue(t reflect.Type) bool {
+	if known, ok := valueTypes.Load(t); ok {
+		return known.(bool)
+	}
+	result := t == timeType
+	if !result {
+		switch t.Kind() {
+		case reflect.Bool, reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+			reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr,
+			reflect.Float32, reflect.Float64, reflect.Complex64, reflect.Complex128, reflect.String:
+			result = true
+		case reflect.Array:
+			result = simpleValue(t.Elem())
+		case reflect.Struct:
+			result = !forbidden(t)
+			for i := 0; result && i < t.NumField(); i++ {
+				result = simpleValue(t.Field(i).Type)
+			}
+		}
+	}
+	valueTypes.Store(t, result)
+	return result
+}
+
+type reference struct {
+	kind             reflect.Kind
+	typ              reflect.Type
+	ptr              uintptr
+	length, capacity int
+}
+
+func identity(v reflect.Value) reference {
+	r := reference{kind: v.Kind(), typ: v.Type(), ptr: uintptr(v.UnsafePointer())}
+	if v.Kind() == reflect.Slice {
+		r.length = v.Len()
+		r.capacity = v.Cap()
+	}
+	return r
+}
+
+type span struct{ start, end uintptr }
+type graph struct {
+	maps   map[uintptr]bool
+	spans  []span
+	maxEnd []uintptr
+}
+
+// References are inspected without reading private values through Interface or
+// using unsafe writes. Slice capacity matters: returning source[:0] is an alias.
+func scanGraph(v reflect.Value, visit func(reflect.Value, string) error) error {
+	seen := map[reference]bool{}
+	nodes := 0
+	var walk func(reflect.Value, string, int) error
+	walk = func(v reflect.Value, path string, depth int) error {
+		nodes++
+		if depth > maxDepth || nodes > maxNodes {
+			return at(path, ErrLimit)
+		}
+		if !v.IsValid() {
+			return nil
+		}
+		if err := visit(v, path); err != nil {
+			return err
+		}
+		if simpleValue(v.Type()) {
+			return nil
+		} // time.Time is a documented immutable value.
+		switch v.Kind() {
+		case reflect.Interface:
+			if !v.IsNil() {
+				return walk(v.Elem(), path, depth+1)
+			}
+		case reflect.Pointer, reflect.Map, reflect.Slice:
+			if v.IsNil() {
+				return nil
+			}
+			id := identity(v)
+			if seen[id] {
+				return nil
+			}
+			seen[id] = true
+			switch v.Kind() {
+			case reflect.Pointer:
+				return walk(v.Elem(), path, depth+1)
+			case reflect.Map:
+				it := v.MapRange()
+				for it.Next() {
+					if err := walk(it.Key(), path+"[key]", depth+1); err != nil {
+						return err
+					}
+					if err := walk(it.Value(), path+"[value]", depth+1); err != nil {
+						return err
+					}
+				}
+			case reflect.Slice:
+				if simpleValue(v.Type().Elem()) {
+					return nil
+				}
+				all := v.Slice(0, v.Cap())
+				for i := 0; i < all.Len(); i++ {
+					if err := walk(all.Index(i), fmt.Sprintf("%s[%d]", path, i), depth+1); err != nil {
+						return err
+					}
+				}
+			}
+		case reflect.Struct:
+			for i := 0; i < v.NumField(); i++ {
+				if err := walk(v.Field(i), path+"."+v.Type().Field(i).Name, depth+1); err != nil {
+					return err
+				}
+			}
+		case reflect.Array:
+			for i := 0; i < v.Len(); i++ {
+				if err := walk(v.Index(i), fmt.Sprintf("%s[%d]", path, i), depth+1); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	}
+	return walk(v, "$", 0)
+}
+func mutableSpan(v reflect.Value) (span, bool) {
+	var n uintptr
+	switch v.Kind() {
+	case reflect.Pointer:
+		if v.IsNil() {
+			return span{}, false
+		}
+		n = v.Type().Elem().Size()
+	case reflect.Slice:
+		if v.IsNil() {
+			return span{}, false
+		}
+		n = uintptr(v.Cap()) * v.Type().Elem().Size()
+	default:
+		return span{}, false
+	}
+	if n == 0 {
+		return span{}, false
+	}
+	start := uintptr(v.UnsafePointer())
+	return span{start, start + n}, true
+}
+func sourceGraph(v reflect.Value) (*graph, error) {
+	g := &graph{maps: map[uintptr]bool{}}
+	err := scanGraph(v, func(v reflect.Value, _ string) error {
+		if r, ok := mutableSpan(v); ok {
+			g.spans = append(g.spans, r)
+		}
+		if v.Kind() == reflect.Map && !v.IsNil() {
+			g.maps[uintptr(v.UnsafePointer())] = true
+		}
+		return nil
+	})
+	sort.Slice(g.spans, func(i, j int) bool { return g.spans[i].start < g.spans[j].start })
+	var end uintptr
+	for _, r := range g.spans {
+		if r.end > end {
+			end = r.end
+		}
+		g.maxEnd = append(g.maxEnd, end)
+	}
+	return g, err
+}
+func (g *graph) audit(v reflect.Value) error {
+	return scanGraph(v, func(v reflect.Value, path string) error {
+		if forbidden(v.Type()) {
+			return at(path, ErrUnsupported)
+		}
+		switch v.Kind() {
+		case reflect.Func, reflect.Chan:
+			if !v.IsNil() {
+				return at(path, ErrUnsupported)
+			}
+		case reflect.UnsafePointer:
+			if v.Pointer() != 0 {
+				return at(path, ErrUnsupported)
+			}
+		}
+		if v.Kind() == reflect.Map && !v.IsNil() && g.maps[uintptr(v.UnsafePointer())] {
+			return at(path, ErrSharedReference)
+		}
+		if r, ok := mutableSpan(v); ok {
+			i := sort.Search(len(g.spans), func(i int) bool { return g.spans[i].start >= r.end })
+			if i > 0 && g.maxEnd[i-1] > r.start {
+				return at(path, ErrSharedReference)
+			}
+		}
+		return nil
+	})
+}
+func forbidden(t reflect.Type) bool {
+	// Lock/resource implementations are not data. A custom converter may turn
+	// them into a different data type but may not manufacture cloned handles.
+	switch t.PkgPath() {
+	case "sync", "sync/atomic", "os", "net", "database/sql":
+		return t.Kind() == reflect.Struct
+	}
+	return false
+}
+
+// Shallow copies may share handles through pointers, but must not copy lock or
+// resource state by value, including state inside a containing struct/array.
+var safeValueTypes sync.Map
+
+func shallowSafe(t reflect.Type) bool {
+	if known, ok := safeValueTypes.Load(t); ok {
+		return known.(bool)
+	}
+	result := true
+	if forbidden(t) {
+		safeValueTypes.Store(t, false)
+		return false
+	}
+	switch t.Kind() {
+	case reflect.Struct:
+		for i := 0; i < t.NumField(); i++ {
+			if !shallowSafe(t.Field(i).Type) {
+				result = false
+				break
+			}
+		}
+	case reflect.Array:
+		result = shallowSafe(t.Elem())
+	}
+	safeValueTypes.Store(t, result)
+	return result
+}
+
+func privateMutable(t reflect.Type) bool {
+	if t == timeType {
+		return false
+	}
+	switch t.Kind() {
+	case reflect.Pointer, reflect.Map, reflect.Slice, reflect.Interface, reflect.Func, reflect.Chan, reflect.UnsafePointer:
+		return true
+	case reflect.Array:
+		return privateMutable(t.Elem())
+	case reflect.Struct:
+		if forbidden(t) {
+			return true
+		}
+		for i := 0; i < t.NumField(); i++ {
+			if privateMutable(t.Field(i).Type) {
+				return true
+			}
+		}
+	}
+	return false
+}
diff --git a/copyx/options.go b/copyx/options.go
new file mode 100644
index 0000000..f80745b
--- /dev/null
+++ b/copyx/options.go
@@ -0,0 +1,169 @@
+// Package copyx copies Go values without JSON, generated code or global registration.
+package copyx
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+)
+
+// NilPolicy controls nil input. NilError preserves nil for nullable targets and
+// rejects nil to non-nullable targets. NilSkip retains the existing target.
+type NilPolicy uint8
+
+const (
+	NilError NilPolicy = iota
+	NilZero
+	NilSkip
+)
+
+type pair struct{ from, to reflect.Type }
+type converter func(reflect.Value) (reflect.Value, error)
+type fields struct {
+	names                      map[string]string
+	ignoreSource, ignoreTarget map[string]bool
+}
+type settings struct {
+	deep, skipZero, strict bool
+	nilPolicy              NilPolicy
+	converters             map[pair]converter
+	fields                 map[pair]*fields
+}
+
+// Option configures one immutable Copier. Options never change global behavior.
+type Option func(*settings) error
+
+func WithDeepCopy() Option { return func(s *settings) error { s.deep = true; return nil } }
+
+// WithSkipZero explicitly skips Go zero values, including false, 0 and "".
+func WithSkipZero() Option { return func(s *settings) error { s.skipZero = true; return nil } }
+
+// WithStrictFields additionally rejects unconsumed exported source fields.
+// Target fields must have a source by default, unless explicitly ignored.
+func WithStrictFields() Option { return func(s *settings) error { s.strict = true; return nil } }
+func WithNilPolicy(p NilPolicy) Option {
+	return func(s *settings) error {
+		if p > NilSkip {
+			return errors.New("copyx: invalid nil policy")
+		}
+		s.nilPolicy = p
+		return nil
+	}
+}
+
+// WithConverter registers an exact source/target type pair. Typed nils are
+// delivered to converters before default nil handling. The function must not
+// mutate its input and must be safe for concurrent calls when Copier is shared.
+func WithConverter[S, T any](fn func(S) (T, error)) Option {
+	return func(s *settings) error {
+		if fn == nil {
+			return errors.New("copyx: nil converter")
+		}
+		key := pair{reflect.TypeFor[S](), reflect.TypeFor[T]()}
+		if _, exists := s.converters[key]; exists {
+			return fmt.Errorf("copyx: duplicate converter %s -> %s", key.from, key.to)
+		}
+		s.converters[key] = func(v reflect.Value) (reflect.Value, error) {
+			var input S
+			reflect.ValueOf(&input).Elem().Set(v)
+			out, err := fn(input)
+			return reflect.ValueOf(&out).Elem(), err
+		}
+		return nil
+	}
+}
+
+// WithFieldNames declares source -> target Go field names for one struct pair.
+// It is not a JSON tag mapping. Only actual, unambiguous exported fields qualify.
+func WithFieldNames[S, T any](names map[string]string) Option {
+	copyNames := make(map[string]string, len(names))
+	for k, v := range names {
+		copyNames[k] = v
+	}
+	return fieldOption[S, T](func(f *fields) error {
+		for from, to := range copyNames {
+			if _, exists := f.names[from]; exists {
+				return fmt.Errorf("copyx: duplicate field rule %s", from)
+			}
+			f.names[from] = to
+		}
+		return nil
+	})
+}
+func WithIgnoreSource[S, T any](names ...string) Option {
+	names = append([]string(nil), names...)
+	return fieldOption[S, T](func(f *fields) error {
+		for _, n := range names {
+			f.ignoreSource[n] = true
+		}
+		return nil
+	})
+}
+
+// WithIgnoreTarget preserves the corresponding existing target fields in Copy.
+// Deep mode rejects that preservation if it would retain a source reference.
+func WithIgnoreTarget[S, T any](names ...string) Option {
+	names = append([]string(nil), names...)
+	return fieldOption[S, T](func(f *fields) error {
+		for _, n := range names {
+			f.ignoreTarget[n] = true
+		}
+		return nil
+	})
+}
+func fieldOption[S, T any](apply func(*fields) error) Option {
+	return func(s *settings) error {
+		key := pair{reflect.TypeFor[S](), reflect.TypeFor[T]()}
+		if key.from.Kind() != reflect.Struct || key.to.Kind() != reflect.Struct {
+			return errors.New("copyx: field options require struct types")
+		}
+		f := s.fields[key]
+		if f == nil {
+			f = &fields{map[string]string{}, map[string]bool{}, map[string]bool{}}
+			s.fields[key] = f
+		}
+		return apply(f)
+	}
+}
+
+// Copier is immutable after construction. Each Copy owns its traversal state.
+type Copier struct{ options settings }
+
+func New(options ...Option) (*Copier, error) {
+	s := settings{converters: map[pair]converter{}, fields: map[pair]*fields{}}
+	for _, option := range options {
+		if option == nil {
+			return nil, errors.New("copyx: nil option")
+		}
+		if err := option(&s); err != nil {
+			return nil, err
+		}
+	}
+	for key, f := range s.fields {
+		from, to := exportedFields(key.from), exportedFields(key.to)
+		used := map[string]bool{}
+		for src, dst := range f.names {
+			if _, ok := from[src]; !ok {
+				return nil, fmt.Errorf("copyx: unknown source field %s.%s", key.from, src)
+			}
+			if _, ok := to[dst]; !ok {
+				return nil, fmt.Errorf("copyx: unknown target field %s.%s", key.to, dst)
+			}
+			if used[dst] || f.ignoreSource[src] || f.ignoreTarget[dst] {
+				return nil, fmt.Errorf("copyx: conflicting field rule %s", dst)
+			}
+			used[dst] = true
+		}
+		for n := range f.ignoreSource {
+			if _, ok := from[n]; !ok {
+				return nil, fmt.Errorf("copyx: unknown source field %s", n)
+			}
+		}
+		for n := range f.ignoreTarget {
+			if _, ok := to[n]; !ok {
+				return nil, fmt.Errorf("copyx: unknown target field %s", n)
+			}
+		}
+	}
+	return &Copier{options: s}, nil
+}
diff --git a/examples/copying/README.md b/examples/copying/README.md
new file mode 100644
index 0000000..5a2367f
--- /dev/null
+++ b/examples/copying/README.md
@@ -0,0 +1,23 @@
+# 结构复制示例
+
+在框架仓库根目录运行 `go run ./examples/copying`；不需要数据库、网络服务或 JSON 映射配置。
+
+示例包含：可复用构造器、Go 字段改名、时间自定义转换、保留 false、深拷贝切片、同类型 Clone，以及拒绝自定义转换器返回输入的原切片。
+
+预期输出：
+
+```text
+name=sample enabled=false time=2026-01-01T00:00:00Z sourceTag=original
+clone detached: true
+shared converter rejected: true
+```
+
+测试：`go test -race ./examples/copying`。完整策略、限制与旧生成映射迁移见 [COPY.md](../../COPY.md)。
+
+独立工资三端的实际生成、HTTP 与金额用例见 [集成测试](../../cmd/go-omni/apigen/copyConsumer_test.go) 和 [公共契约](../../cmd/go-omni/apigen/testdata/composition/service.api)。框架根目录运行：
+
+```sh
+GO_OMNI_SCAFFOLD_INTEGRATION=1 go test ./cmd/go-omni/apigen -run TestCopyxThreeEndpointConsumer -count=1
+```
+
+该测试在临时独立项目中执行，三个入口共用一个普通 Go copyx helper。公共字段新增时，只修改公共契约和独立业务结构，三个入口的转换规则不增加。
diff --git a/examples/copying/main.go b/examples/copying/main.go
new file mode 100644
index 0000000..d652d15
--- /dev/null
+++ b/examples/copying/main.go
@@ -0,0 +1,61 @@
+// copying demonstrates optional Go-to-Go conversion and checked deep copying.
+package main
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"time"
+
+	"git.yuntuo.hk/k2safe/go-omni/copyx"
+)
+
+type Input struct {
+	Name      string
+	Enabled   bool
+	Tags      []string
+	CreatedAt time.Time
+}
+type View struct {
+	DisplayName string
+	Enabled     bool
+	Tags        []string
+	CreatedAt   string
+}
+
+func run() error {
+	converter, err := copyx.New(
+		copyx.WithDeepCopy(),
+		copyx.WithFieldNames[Input, View](map[string]string{"Name": "DisplayName"}),
+		copyx.WithConverter(func(v time.Time) (string, error) { return v.UTC().Format(time.RFC3339), nil }),
+	)
+	if err != nil {
+		return err
+	}
+	source := Input{Name: "sample", Enabled: false, Tags: []string{"original"}, CreatedAt: time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)}
+	var target View
+	if err = converter.Copy(&target, source); err != nil {
+		return err
+	}
+	target.Tags[0] = "changed"
+	fmt.Printf("name=%s enabled=%t time=%s sourceTag=%s\n", target.DisplayName, target.Enabled, target.CreatedAt, source.Tags[0])
+
+	cloned, err := copyx.Clone(source)
+	if err != nil {
+		return err
+	}
+	cloned.Tags[0] = "separate"
+	fmt.Println("clone detached:", source.Tags[0] == "original")
+
+	_, err = copyx.Clone(source.Tags, copyx.WithConverter(func(v []string) ([]string, error) { return v, nil }))
+	fmt.Println("shared converter rejected:", errors.Is(err, copyx.ErrSharedReference))
+	if !errors.Is(err, copyx.ErrSharedReference) {
+		return errors.New("expected alias rejection")
+	}
+	return nil
+}
+func main() {
+	if err := run(); err != nil {
+		log.Fatal(err)
+	}
+}
diff --git a/examples/copying/main_test.go b/examples/copying/main_test.go
new file mode 100644
index 0000000..b0e283d
--- /dev/null
+++ b/examples/copying/main_test.go
@@ -0,0 +1,9 @@
+package main
+
+import "testing"
+
+func TestExample(t *testing.T) {
+	if err := run(); err != nil {
+		t.Fatal(err)
+	}
+}
diff --git a/examples/managedService/.goOmni/apiManifest.json b/examples/managedService/.goOmni/apiManifest.json
index 92217cc..9812898 100644
--- a/examples/managedService/.goOmni/apiManifest.json
+++ b/examples/managedService/.goOmni/apiManifest.json
@@ -1,6 +1,6 @@
 {
   "generatorConfig": true,
-  "templateVersion": "v0.18.0-preview",
+  "templateVersion": "v0.19.0-preview",
   "profile": {
     "database": "none",
     "storage": "none",
diff --git a/examples/managedService/go.mod b/examples/managedService/go.mod
index 00a39f6..edc3717 100644
--- a/examples/managedService/go.mod
+++ b/examples/managedService/go.mod
@@ -2,7 +2,7 @@ module example.com/managed
 
 go 1.22.0
 
-require git.yuntuo.hk/k2safe/go-omni v0.18.0-preview
+require git.yuntuo.hk/k2safe/go-omni v0.19.0-preview
 
 require (
 	github.com/gabriel-vasile/mimetype v1.4.3 // indirect
diff --git a/reports/copyxAcceptance.md b/reports/copyxAcceptance.md
new file mode 100644
index 0000000..52febfb
--- /dev/null
+++ b/reports/copyxAcceptance.md
@@ -0,0 +1,70 @@
+# v0.19 copyx 与映射移除验收
+
+日期：2026-09-25。环境：Apple M2 Max、darwin/arm64、Go 1.27.1，基准默认 GOMAXPROCS=12。最低支持版本另用 Go 1.22.12 验证 copyx 与可运行示例。
+
+## 范围与行为
+
+本轮新增可选 Go 工具包并删除原映射配置/生成机制，没有修改接入项目代码、数据库或线上服务。没有新增第三方依赖，没有内置工资、金额或权限规则；工资只是生成器的独立通用验收 fixture。
+
+| 场景 | 验证内容 |
+| --- | --- |
+| 浅/深复制 | 值、结构、指针、数组、map、slice、interface；浅共享与深隔离分别验证 |
+| 空值与精度 | nil 与空集合、默认保留 false/0、显式 nil/skip 策略；不兼容类型不能借 nil/零值绕过检查 |
+| 可变引用 | 原指针/map、子切片、零长度但有容量的视图、源元素指针、私有子引用、其他字段的引用均拒绝 |
+| 自定义函数 | 字段改名、精确类型对、金额私有状态复制、nil interface；重复/冲突配置拒绝 |
+| 失败语义 | errors.Is 保留 cause、目标不提交部分结果、嵌入目标指针不提前修改 |
+| 对象图 | 指针/map/slice 循环，重复引用；循环指针根压成值结构拒绝 |
+| 并发与资源 | 同一 Copier 64 goroutine 各复制 20 次，race；深度/节点/估算分配超限拒绝；锁/资源/函数等明确限制 |
+| 真正生成的消费者 | 三端工资公共字段，Money scalar，大数精度/舍入、非法金额、缺失/null/零值、完整表单、错误码与错误链 |
+| 维护成本 | 公共字段新增：改一处契约和一处独立业务结构；三个接口共用 helper，不增加拷贝规则 |
+| 生成与生命周期 | 重复 generate/check/dry-run 保留业务文件；工厂异常、初始化/监听失败及资源关闭由既有回归验证 |
+| 移除与 workspace | 旧配置/旧生成文件阻断且不写入，明确迁移后所有权清理；workspace 失败不部分更新服务 |
+
+FuzzClone 使用动态 JSON 容器、随机 bytes 和嵌套 slice，验证值一致与引用隔离。输入超过 1 KiB 时截取继续验证，运行 30 秒、4 workers：**4,237,917 次执行，未发现失败**。这不等于所有形状都已 fuzz；循环、类型转换及资源拒绝另外用定向用例覆盖。
+
+全量 46 个测试包通过 race 回归（含实际生成项目），vet/build、Go 1.22.12、示例运行与生成漂移检查均通过。
+
+## 可复现命令
+
+```sh
+GO_OMNI_SCAFFOLD_INTEGRATION=1 go test -race -count=1 ./...
+go vet ./...
+go build ./...
+GOTOOLCHAIN=go1.22.12 go test ./copyx ./examples/copying
+go test ./copyx -run '^$' -fuzz FuzzClone -fuzztime 30s -parallel 4
+go test ./copyx -run '^$' -bench . -benchmem -benchtime 300ms -count 3
+go run ./examples/copying
+go run ./cmd/go-omni api generate --dir examples/managedService --check
+# examples/managedService 中另执行 go test -race ./... 与 go build .
+```
+
+全量回归包含真实临时生成项目，集成测试的子进程使用 go test -race / go build，并不只比较生成字符串。基准测量时没有同时运行本轮 fuzz 或全量测试；原始三轮结果见 [copyxBenchmark.txt](copyxBenchmark.txt)。
+
+## 性能与分配
+
+下表取三轮中位数。构造器复用与一次性调用都包含真实复制；`fields1000` 指整数 slice 的长度，不是 1,000 个结构字段。所有深拷贝保留引用检查。
+
+| 场景 | 中位耗时 | B/op | allocs/op |
+| --- | ---: | ---: | ---: |
+| 相同结构浅拷贝（含引用字段） | 85.8 ns | 96 | 2 |
+| 3 字段跨结构改名，复用 Copier | 697.5 ns | 168 | 7 |
+| 相同跨结构，每次构建 Copier | 1,181 ns | 1,120 | 17 |
+| 嵌套结构 + 1 个整数 + map，深拷贝 | 2,758 ns | 1,368 | 42 |
+| 嵌套结构 + 100 个整数 + map，深拷贝 | 2,787 ns | 2,256 | 42 |
+| 嵌套结构 + 1,000 个整数 + map，深拷贝 | 3,806 ns | 9,552 | 42 |
+| 64 KiB byte slice 深拷贝 | 5,780 ns | 65,768 | 9 |
+| 100 项 map，每项含整数 slice | 88,859 ns | 87,704 | 1,554 |
+| 自引用循环对象深拷贝 | 2,128 ns | 640 | 26 |
+| converter 新建 slice 并通过检查 | 539.7 ns | 280 | 10 |
+| converter 返回原 slice 被拒绝 | 383.8 ns | 320 | 11 |
+
+并行循环对象基准中位 515.2 ns/op 是多核聚合吞吐均摊，**不是单请求延迟**。复杂 map 的多次图扫描、字段路径和反射分配明显更贵；不据此宣称运行时工具快于手写赋值。热点复用 Copier；大对象和高频映射应按实际业务结构衡量是否改用直接 Go。
+
+优化只包括不可变类型元数据缓存、纯值快速路径、纯值 slice 批量复制；没有去掉深拷贝别名检查。内置估算分配上限 64 MiB 不是硬堆内存隔离，converter 的外部分配及副作用不受该预算控制。
+
+## 边界
+
+- 新方式在运行时做类型与覆盖检查，不再有旧映射生成时的静态保证；字段变更要运行实际类型对测试。
+- converter 是受信项目代码，必须只读输入；不能自动回滚其副作用、证明其未共享外部全局对象，或强杀无限循环。
+- 当前记录是本机库/生成器验收，不是线上服务吞吐、Linux soak、真实业务数据库回归或 OSS/R2 云账号验收。本轮没有对线上服务器施压。
+- 旧消费者仍需按 [COPY.md](../COPY.md#从旧-mapping-迁移) 迁移，不会被这次框架发布自动修改。
diff --git a/reports/copyxBenchmark.txt b/reports/copyxBenchmark.txt
new file mode 100644
index 0000000..8c11549
--- /dev/null
+++ b/reports/copyxBenchmark.txt
@@ -0,0 +1,48 @@
+goos: darwin
+goarch: arm64
+pkg: git.yuntuo.hk/k2safe/go-omni/copyx
+cpu: Apple M2 Max
+BenchmarkScenarios/struct/reusefalse-12         	  251924	      1209 ns/op	    1120 B/op	      17 allocs/op
+BenchmarkScenarios/struct/reusefalse-12         	  316450	      1181 ns/op	    1120 B/op	      17 allocs/op
+BenchmarkScenarios/struct/reusefalse-12         	  314466	      1140 ns/op	    1120 B/op	      17 allocs/op
+BenchmarkScenarios/struct/reusetrue-12          	  517544	       703.0 ns/op	     168 B/op	       7 allocs/op
+BenchmarkScenarios/struct/reusetrue-12          	  517842	       691.9 ns/op	     168 B/op	       7 allocs/op
+BenchmarkScenarios/struct/reusetrue-12          	  522170	       697.5 ns/op	     168 B/op	       7 allocs/op
+BenchmarkScenarios/bytes64KiB-12                	   67933	      5857 ns/op	11189.69 MB/s	   65768 B/op	       9 allocs/op
+BenchmarkScenarios/bytes64KiB-12                	   61680	      5780 ns/op	11337.56 MB/s	   65768 B/op	       9 allocs/op
+BenchmarkScenarios/bytes64KiB-12                	   61843	      5771 ns/op	11355.66 MB/s	   65768 B/op	       9 allocs/op
+BenchmarkScenarios/map100-12                    	    3808	     88598 ns/op	   87704 B/op	    1554 allocs/op
+BenchmarkScenarios/map100-12                    	    4136	     88859 ns/op	   87704 B/op	    1554 allocs/op
+BenchmarkScenarios/map100-12                    	    4051	     89614 ns/op	   87704 B/op	    1554 allocs/op
+BenchmarkScenarios/cycle-12                     	  168308	      2128 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/cycle-12                     	  169057	      2163 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/cycle-12                     	  169892	      2120 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/parallelCycle-12             	  963274	       660.6 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/parallelCycle-12             	  582906	       515.1 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/parallelCycle-12             	  748388	       515.2 ns/op	     640 B/op	      26 allocs/op
+BenchmarkScenarios/converter/freshfalse-12      	  828752	       382.8 ns/op	     320 B/op	      11 allocs/op
+BenchmarkScenarios/converter/freshfalse-12      	  897363	       383.8 ns/op	     320 B/op	      11 allocs/op
+BenchmarkScenarios/converter/freshfalse-12      	 1000000	       387.5 ns/op	     320 B/op	      11 allocs/op
+BenchmarkScenarios/converter/freshtrue-12       	  665454	       541.2 ns/op	     280 B/op	      10 allocs/op
+BenchmarkScenarios/converter/freshtrue-12       	  647089	       535.0 ns/op	     280 B/op	      10 allocs/op
+BenchmarkScenarios/converter/freshtrue-12       	  704719	       539.7 ns/op	     280 B/op	      10 allocs/op
+BenchmarkCopy/fields1/deepfalse-12              	 4058166	        87.96 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1/deepfalse-12              	 4137807	        85.79 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1/deepfalse-12              	 4201804	        85.07 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1/deeptrue-12               	  131413	      2739 ns/op	    1368 B/op	      42 allocs/op
+BenchmarkCopy/fields1/deeptrue-12               	  131658	      2771 ns/op	    1368 B/op	      42 allocs/op
+BenchmarkCopy/fields1/deeptrue-12               	  131880	      2758 ns/op	    1368 B/op	      42 allocs/op
+BenchmarkCopy/fields100/deepfalse-12            	 4209133	        85.61 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields100/deepfalse-12            	 4239586	        84.30 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields100/deepfalse-12            	 4248972	        84.59 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields100/deeptrue-12             	  127617	      2787 ns/op	    2256 B/op	      42 allocs/op
+BenchmarkCopy/fields100/deeptrue-12             	  129816	      2826 ns/op	    2256 B/op	      42 allocs/op
+BenchmarkCopy/fields100/deeptrue-12             	  124041	      2780 ns/op	    2256 B/op	      42 allocs/op
+BenchmarkCopy/fields1000/deepfalse-12           	 4214600	        85.59 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1000/deepfalse-12           	 4250719	        85.20 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1000/deepfalse-12           	 4247498	        85.05 ns/op	      96 B/op	       2 allocs/op
+BenchmarkCopy/fields1000/deeptrue-12            	   92329	      3818 ns/op	    9552 B/op	      42 allocs/op
+BenchmarkCopy/fields1000/deeptrue-12            	   93945	      3806 ns/op	    9552 B/op	      42 allocs/op
+BenchmarkCopy/fields1000/deeptrue-12            	   96010	      3782 ns/op	    9552 B/op	      42 allocs/op
+PASS
+ok  	git.yuntuo.hk/k2safe/go-omni/copyx	17.513s
diff --git a/reports/copyxFuzz.txt b/reports/copyxFuzz.txt
new file mode 100644
index 0000000..865abcd
--- /dev/null
+++ b/reports/copyxFuzz.txt
@@ -0,0 +1,15 @@
+fuzz: elapsed: 0s, gathering baseline coverage: 0/10 completed
+fuzz: elapsed: 0s, gathering baseline coverage: 10/10 completed, now fuzzing with 4 workers
+fuzz: elapsed: 3s, execs: 426851 (142240/sec), new interesting: 5 (total: 15)
+fuzz: elapsed: 6s, execs: 837791 (137019/sec), new interesting: 5 (total: 15)
+fuzz: elapsed: 9s, execs: 1281087 (147767/sec), new interesting: 5 (total: 15)
+fuzz: elapsed: 12s, execs: 1705531 (141463/sec), new interesting: 5 (total: 15)
+fuzz: elapsed: 15s, execs: 2125995 (140169/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 18s, execs: 2547285 (140432/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 21s, execs: 2954940 (135854/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 24s, execs: 3389762 (144941/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 27s, execs: 3808273 (139491/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 30s, execs: 4237917 (143257/sec), new interesting: 6 (total: 16)
+fuzz: elapsed: 30s, execs: 4237917 (0/sec), new interesting: 6 (total: 16)
+PASS
+ok  	git.yuntuo.hk/k2safe/go-omni/copyx	30.363s
diff --git a/reports/copyxRegression.txt b/reports/copyxRegression.txt
new file mode 100644
index 0000000..917b4d7
--- /dev/null
+++ b/reports/copyxRegression.txt
@@ -0,0 +1,59 @@
+ok  	git.yuntuo.hk/k2safe/go-omni	1.519s
+ok  	git.yuntuo.hk/k2safe/go-omni/app	3.503s
+ok  	git.yuntuo.hk/k2safe/go-omni/audit	1.970s
+ok  	git.yuntuo.hk/k2safe/go-omni/auth	2.265s
+ok  	git.yuntuo.hk/k2safe/go-omni/cache	2.566s
+ok  	git.yuntuo.hk/k2safe/go-omni/cache/redis	2.712s
+ok  	git.yuntuo.hk/k2safe/go-omni/cmd/go-omni	5.321s
+ok  	git.yuntuo.hk/k2safe/go-omni/cmd/go-omni/apigen	76.921s
+ok  	git.yuntuo.hk/k2safe/go-omni/cmd/go-omni/scaffold	47.757s
+ok  	git.yuntuo.hk/k2safe/go-omni/config	4.374s
+ok  	git.yuntuo.hk/k2safe/go-omni/contract	4.702s
+ok  	git.yuntuo.hk/k2safe/go-omni/copyx	5.171s
+ok  	git.yuntuo.hk/k2safe/go-omni/database	4.141s
+ok  	git.yuntuo.hk/k2safe/go-omni/database/gormx	3.916s
+ok  	git.yuntuo.hk/k2safe/go-omni/database/migrate	3.856s
+ok  	git.yuntuo.hk/k2safe/go-omni/database/mysql	3.816s
+ok  	git.yuntuo.hk/k2safe/go-omni/errors	3.930s
+?   	git.yuntuo.hk/k2safe/go-omni/examples/basic	[no test files]
+?   	git.yuntuo.hk/k2safe/go-omni/examples/compatibility	[no test files]
+?   	git.yuntuo.hk/k2safe/go-omni/examples/compatibility/ids	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/examples/copying	3.198s
+ok  	git.yuntuo.hk/k2safe/go-omni/examples/modules	2.930s
+ok  	git.yuntuo.hk/k2safe/go-omni/examples/platform	2.766s
+ok  	git.yuntuo.hk/k2safe/go-omni/examples/reference	2.794s
+?   	git.yuntuo.hk/k2safe/go-omni/examples/reference/handler	[no test files]
+?   	git.yuntuo.hk/k2safe/go-omni/examples/reference/model	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/examples/reference/repository	2.880s
+?   	git.yuntuo.hk/k2safe/go-omni/examples/reference/service	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/health	3.091s
+ok  	git.yuntuo.hk/k2safe/go-omni/httpc	3.345s
+ok  	git.yuntuo.hk/k2safe/go-omni/httpx	3.870s
+ok  	git.yuntuo.hk/k2safe/go-omni/internal/perfcheck	3.284s
+?   	git.yuntuo.hk/k2safe/go-omni/internal/storagefixture	[no test files]
+?   	git.yuntuo.hk/k2safe/go-omni/internal/testutil	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/lifecycle	3.390s
+ok  	git.yuntuo.hk/k2safe/go-omni/logx	3.459s
+ok  	git.yuntuo.hk/k2safe/go-omni/metrics	2.732s
+ok  	git.yuntuo.hk/k2safe/go-omni/middleware	2.718s
+ok  	git.yuntuo.hk/k2safe/go-omni/middleware/redis	3.086s
+ok  	git.yuntuo.hk/k2safe/go-omni/openapi	3.319s
+ok  	git.yuntuo.hk/k2safe/go-omni/pagination	3.356s
+?   	git.yuntuo.hk/k2safe/go-omni/queue	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/queue/redis	3.060s
+ok  	git.yuntuo.hk/k2safe/go-omni/resilience	2.898s
+ok  	git.yuntuo.hk/k2safe/go-omni/response	3.157s
+ok  	git.yuntuo.hk/k2safe/go-omni/storage	3.414s
+ok  	git.yuntuo.hk/k2safe/go-omni/storage/local	3.617s
+ok  	git.yuntuo.hk/k2safe/go-omni/storage/oss	3.572s
+ok  	git.yuntuo.hk/k2safe/go-omni/storage/s3	3.752s
+?   	git.yuntuo.hk/k2safe/go-omni/storage/storagetest	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/task	3.094s
+ok  	git.yuntuo.hk/k2safe/go-omni/telemetry	3.089s
+ok  	git.yuntuo.hk/k2safe/go-omni/transport	3.311s
+ok  	git.yuntuo.hk/k2safe/go-omni/transport/http2	14.938s
+?   	git.yuntuo.hk/k2safe/go-omni/transport/internal/routing	[no test files]
+ok  	git.yuntuo.hk/k2safe/go-omni/transport/native	4.422s
+ok  	git.yuntuo.hk/k2safe/go-omni/transport/nethttp	3.401s
+?   	git.yuntuo.hk/k2safe/go-omni/transport/transporttest	[no test files]
+?   	git.yuntuo.hk/k2safe/go-omni/validate	[no test files]