diff --git a/AGENTS.md b/AGENTS.md
index 1f46f91..3e3d457 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -50,6 +50,8 @@
 ## 10. 代码与流程硬性规范（压缩后仍需遵守）
 - 🔴 **文件 ≤500 行、函数 ≤80 行**；**模块按职责拆成多个源文件，严禁把整个模块塞进一个超大文件**；**三次复制必须抽取**共享。
 - 🔴 禁 `interface{}`（用 `any`）、禁包级全局变量（除 `var ErrXxx`）、禁裸 `return err`、禁魔法数字；错误一律 `%w` wrap；SQL 全参数化、表名单数、主键 `id`、时间戳 `created_at/updated_at`、索引 `idx_{table}_{col}`；敏感信息打日志。
+- 🔴 **日志必须标来源**：模块/子功能用 `internal/logger.WithSource`/`Scoped`（`source=module/subfeature`）标注，跨模块可追溯定位；**禁止无来源裸日志**。
+- 🔴 **客户端 API 契约先行**：REST `/api/v1` + WS `/ws` + admin `/api/v1/admin/*` 统一**版本化契约**，供跨平台客户端（Web/移动/IM bridge）接入与治理；JSON 响应 `{data}` / `{error:{code,message}}`。
 - 🔴 每阶段完成（或里程碑归档）后：**`git push origin dev`** 同步远端。
 - 🔴 **遇到开发文档冲突 / 意义不明 / 规格矛盾时**：**阻塞会话**，用 `AskUserQuestion` 询问主人，**不得自行猜测**；文档清、不冲突则自主推进。
 - 🔴 阶段验证：后端 `go build ./...` + `go vet ./...` + `go test ./...` 全绿 + windows/darwin 交叉编译；前端（M9+）`tsc --noEmit` + `vite build` 通过。
diff --git a/internal/logger/logger.go b/internal/logger/logger.go
index a373f2b..d737c7c 100644
--- a/internal/logger/logger.go
+++ b/internal/logger/logger.go
@@ -68,3 +68,24 @@ func ParseLevel(s string) slog.Level {
 		return slog.LevelInfo
 	}
 }
+
+// WithSource returns a child logger that tags every emitted record with a
+// source so issues can be traced back to the owning module/sub-feature. source
+// is conventionally "module/subfeature", e.g. "runtime/loop" or
+// "channel/adapter". Every module that logs should call this once on its base
+// logger so all records carry provenance.
+func WithSource(l *slog.Logger, source string) *slog.Logger {
+	if l == nil {
+		return nil
+	}
+	return l.With(slog.String("source", source))
+}
+
+// Scoped returns a child logger tagged with module and subfeature, for finer
+// provenance when a module contains several subsystems.
+func Scoped(l *slog.Logger, module, subfeature string) *slog.Logger {
+	if l == nil {
+		return nil
+	}
+	return l.With(slog.String("module", module), slog.String("sub", subfeature))
+}
diff --git a/internal/logger/logger_test.go b/internal/logger/logger_test.go
index 5451a2f..6d7e8d9 100644
--- a/internal/logger/logger_test.go
+++ b/internal/logger/logger_test.go
@@ -91,3 +91,28 @@ func TestNew_DefaultsToErrAndText(t *testing.T) {
 		t.Fatal("New(Options{}) returned nil logger")
 	}
 }
+
+func TestWithSource_TagsRecords(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	base := New(Options{Level: "debug", Format: "json", Out: &buf})
+	log := WithSource(base, "runtime/loop")
+	log.Info("hello")
+	if !strings.Contains(buf.String(), `"source":"runtime/loop"`) {
+		t.Fatalf("missing source field, got %q", buf.String())
+	}
+}
+
+func TestScoped_TagsModuleAndSub(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	base := New(Options{Level: "debug", Format: "json", Out: &buf})
+	log := Scoped(base, "channel", "adapter")
+	log.Info("hello")
+	got := buf.String()
+	if !strings.Contains(got, `"module":"channel"`) || !strings.Contains(got, `"sub":"adapter"`) {
+		t.Fatalf("missing module/sub fields, got %q", got)
+	}
+}