diff --git a/DEV-LOG.md b/DEV-LOG.md
index f8e4fe5..124b065 100644
--- a/DEV-LOG.md
+++ b/DEV-LOG.md
@@ -1,5 +1,26 @@
 # DEV-LOG
 
+## Auto Mode 补全 (2026-04-02)
+
+反编译丢失了 auto mode 分类器的三个 prompt 模板文件，代码逻辑完整但无法运行。
+
+**新增：**
+- `yolo-classifier-prompts/auto_mode_system_prompt.txt` — 主系统提示词
+- `yolo-classifier-prompts/permissions_external.txt` — 外部权限模板（用户规则替换默认值）
+- `yolo-classifier-prompts/permissions_anthropic.txt` — 内部权限模板（用户规则追加）
+
+**改动：**
+- `scripts/dev.ts` + `build.ts` — 扫描 `FEATURE_*` 环境变量注入 Bun `--feature`
+- `cli.tsx` — 启动时打印已启用的 feature
+- `permissionSetup.ts` — `AUTO_MODE_ENABLED_DEFAULT` 由 `feature('TRANSCRIPT_CLASSIFIER')` 决定，开 feature 即开 auto mode
+- `docs/safety/auto-mode.mdx` — 补充 prompt 模板章节
+
+**用法：** `FEATURE_TRANSCRIPT_CLASSIFIER=1 bun run dev`
+
+**注意：** prompt 模板为重建产物。
+
+---
+
 ## USER_TYPE=ant TUI 修复 (2026-04-02)
 
 `global.d.ts` 声明的全局函数在反编译版本运行时未定义，导致 `USER_TYPE=ant` 时 TUI 崩溃。
diff --git a/build.ts b/build.ts
index e63498c..b179ec1 100644
--- a/build.ts
+++ b/build.ts
@@ -8,6 +8,11 @@ const outdir = "dist";
 const { rmSync } = await import("fs");
 rmSync(outdir, { recursive: true, force: true });
 
+// Collect FEATURE_* env vars → Bun.build features
+const features = Object.keys(process.env)
+    .filter(k => k.startsWith("FEATURE_"))
+    .map(k => k.replace("FEATURE_", ""));
+
 // Step 2: Bundle with splitting
 const result = await Bun.build({
     entrypoints: ["src/entrypoints/cli.tsx"],
@@ -15,6 +20,7 @@ const result = await Bun.build({
     target: "bun",
     splitting: true,
     define: getMacroDefines(),
+    features,
 });
 
 if (!result.success) {
diff --git a/scripts/dev.ts b/scripts/dev.ts
index 5a9ec8f..865a882 100644
--- a/scripts/dev.ts
+++ b/scripts/dev.ts
@@ -13,8 +13,18 @@ const defineArgs = Object.entries(defines).flatMap(([k, v]) => [
     `${k}:${v}`,
 ]);
 
+// Bun --feature flags: enable feature() gates at runtime.
+// Any env var matching FEATURE_<NAME>=1 will enable that feature.
+// e.g. FEATURE_TRANSCRIPT_CLASSIFIER=1 bun run dev
+const featureArgs: string[] = Object.entries(process.env)
+    .filter(([k]) => k.startsWith("FEATURE_"))
+    .flatMap(([k]) => {
+        const name = k.replace("FEATURE_", "");
+        return ["--feature", name];
+    });
+
 const result = Bun.spawnSync(
-    ["bun", "run", ...defineArgs, "src/entrypoints/cli.tsx", ...process.argv.slice(2)],
+    ["bun", "run", ...defineArgs, ...featureArgs, "src/entrypoints/cli.tsx", ...process.argv.slice(2)],
     { stdio: ["inherit", "inherit", "inherit"] },
 );
 
diff --git a/src/entrypoints/cli.tsx b/src/entrypoints/cli.tsx
index fa377cb..f792f3a 100644
--- a/src/entrypoints/cli.tsx
+++ b/src/entrypoints/cli.tsx
@@ -1,6 +1,12 @@
 #!/usr/bin/env bun
 import { feature } from 'bun:bundle';
 
+// eslint-disable-next-line custom-rules/no-top-level-side-effects
+if (feature('TRANSCRIPT_CLASSIFIER')) {
+  // eslint-disable-next-line custom-rules/no-console, custom-rules/no-top-level-side-effects
+  console.log('[dev] feature TRANSCRIPT_CLASSIFIER enabled');
+}
+
 // Bugfix for corepack auto-pinning, which adds yarnpkg to peoples' package.jsons
 // eslint-disable-next-line custom-rules/no-top-level-side-effects
 process.env.COREPACK_ENABLE_AUTO_PIN = '0';
diff --git a/src/utils/permissions/permissionSetup.ts b/src/utils/permissions/permissionSetup.ts
index 8520da8..700d198 100644
--- a/src/utils/permissions/permissionSetup.ts
+++ b/src/utils/permissions/permissionSetup.ts
@@ -1310,7 +1310,8 @@ export function getAutoModeUnavailableReason(): AutoModeUnavailableReason | null
  */
 export type AutoModeEnabledState = 'enabled' | 'disabled' | 'opt-in'
 
-const AUTO_MODE_ENABLED_DEFAULT: AutoModeEnabledState = 'disabled'
+const AUTO_MODE_ENABLED_DEFAULT: AutoModeEnabledState =
+  feature('TRANSCRIPT_CLASSIFIER') ? 'enabled' : 'disabled'
 
 function parseAutoModeEnabledState(value: unknown): AutoModeEnabledState {
   if (value === 'enabled' || value === 'disabled' || value === 'opt-in') {