diff --git a/AGENTS.md b/AGENTS.md
index e965d44..f4e5c92 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -64,7 +64,7 @@
 - Codex fast mode 只为符合条件的 `openai-codex-responses` 请求设置 priority service tier，由 `/fast-mode` 在会话内控制。
 - 权限策略默认允许常规工具，允许 FFF 工具；拒绝 Bash 直搜和敏感凭据路径；Git 非只读操作、包管理、外部目录、文件/系统/网络高风险操作与普通 MCP 调用先由 `pi-permission-system` 判为 `ask`。
 - `pi-permission-auto-review` 不是独立 `tool_call` gate，而是 `pi-permission-system` authorizer chain 中名为 `auto-review` 的链路；只复核权限基线产生的 `ask`，不会重复处理已 `allow` 或已 `deny` 的请求。
-- reviewer 返回 `allow` 时自动批准、返回 `deny` 时直接拒绝，配置、模型、认证、超时或响应异常时必须 `defer` 到正常人工提示。`pi-permission-system` 的 delegation envelope 继续禁止 authorizer 自动批准全部 `path` 请求；`external_directory` 只对内置 `read` 接受 reviewer 的 `allow`，写入、编辑、Bash、未知工具和其他外部访问仍转人工。
+- reviewer 返回 `allow` 时自动批准、返回 `deny` 时直接拒绝，配置、模型、认证、超时或响应异常时必须 `defer` 到正常人工提示。`pi-permission-system` 的 delegation envelope 继续禁止 authorizer 自动批准全部 `path` 请求；`external_directory` 对内置只读路径工具（`read`、`find`、`grep`、`ls`）接受 reviewer 的 `allow`，写入、编辑、Bash、未知工具和其他外部访问仍转人工。
 - 默认 reviewer 为 `openai-codex/codex-auto-review`、low reasoning、90 秒总重试预算和内置 Codex Guardian 风格策略；只把 active branch 中的直接用户消息与已识别结构化问答作为授权证据，assistant/tool/compaction 内容不能自行授权。
 - `config/pi-permission-system.json` 必须显式配置 `authorizerChain: ["auto-review"]`，并把需要自动复核的 Git 非只读操作、包管理及其他类别声明为 `ask`；硬 `deny` 不得改成可由模型覆盖的 `ask`。
 - `pi-lsp` 的 TypeScript/JavaScript 后端由根包固定依赖提供，`extensions/lsp.ts` 使用当前 Node 可执行文件直接启动包内 `typescript-language-server` CLI，不得依赖或调用 VS Code GUI；Kotlin/JDT LS 仍使用组合包部署的 `kotlin-lsp --stdio` 与 `jdtls` 配置，根包不安装这两个系统可执行文件，便捷脚本可在用户逐项明确确认后通过 Homebrew 安装 Kotlin LSP、Java 21 和 JDT LS。
@@ -113,7 +113,7 @@
 
 - 扩展入口是 `pi-permission-system/src/index.ts`，公共跨扩展服务入口是 `pi-permission-system/src/service.ts`，测试保留在该目录的 `test/`。
 - 同步上游必须从明确 tag/commit 移植并记录快照；保留上游 `LICENSE`、作者和来源，不导入 `dist/`、嵌套 `.git` 或上游包目录的 `.pi` 本地状态。
-- 本地 delegation envelope 只允许内置 `read` 对 `external_directory` 接受 authorizer 的 `allow`；`write`、`edit`、Bash、未知工具、未确定 surface 以及全部 `path` ask 必须继续 `defer` 到终端人工 authority。
+- 本地 delegation envelope 允许内置只读路径工具（`read`、`find`、`grep`、`ls`）对 `external_directory` 接受 authorizer 的 `allow`；`write`、`edit`、Bash、未知工具、未确定 surface 以及全部 `path` ask 必须继续 `defer` 到终端人工 authority。
 - 修改 gate、authorizer chain、delegation envelope、子代理转发或公共 service 类型时，必须同步更新包内 README/架构文档和对应测试。
 - 根包必须通过 `file:./pi-permission-system` 提供运行时依赖，包装入口必须直接加载仓库源码；不得同时加载 npm 预编译入口或第二个 permission-system 实例。
 
diff --git a/README.md b/README.md
index 8fb47db..b7f7707 100644
--- a/README.md
+++ b/README.md
@@ -251,7 +251,7 @@ codegraph status
 
 - `allow`：权限基线已明确允许的常规操作不会调用 reviewer。
 - `deny`：Bash 直搜、敏感凭据路径等硬拒绝不会交给 reviewer，也不能被其绕过。
-- `ask`：Git 非只读操作、包管理、文件/系统/网络/环境操作和普通 MCP 调用交给 reviewer；`path` 仍全部受 delegation envelope 保护。`external_directory` 仅允许内置 `read` 接受 reviewer 的 `allow`，`write`、`edit`、Bash、未知工具及其他外部目录访问仍降级为人工确认。
+- `ask`：Git 非只读操作、包管理、文件/系统/网络/环境操作和普通 MCP 调用交给 reviewer；`path` 仍全部受 delegation envelope 保护。`external_directory` 允许内置只读路径工具（`read`、`find`、`grep`、`ls`）接受 reviewer 的 `allow`，`write`、`edit`、Bash、未知工具及其他外部目录访问仍降级为人工确认。
 
 reviewer 默认使用 `openai-codex/codex-auto-review`、low reasoning 和内置 Codex Guardian 风格策略，并读取当前 session active branch 中的可信用户证据。可通过 `/permission-auto-review` 查看或调整全局/项目配置；无配置时使用源码内置默认值。
 
diff --git a/pi-permission-auto-review/README.md b/pi-permission-auto-review/README.md
index d2cbf99..00caf5a 100644
--- a/pi-permission-auto-review/README.md
+++ b/pi-permission-auto-review/README.md
@@ -106,7 +106,7 @@ Transcript rendering uses separate 10k-token message and tool budgets with per-e
 - Model, authentication, timeout, provider, or response-format failures defer to the normal human prompt.
 - Unexpected internal review failures also defer to the human prompt instead of escaping into the permission gate.
 - Three consecutive denials, or ten denials in the latest fifty reviews, open a circuit breaker until the next Pi turn.
-- my-pi's maintained pi-permission-system keeps every `path` request inside the delegation envelope. For `external_directory`, only the built-in `read` tool may accept an auto-review `allow`; write, edit, bash, unknown tools, and undetermined surfaces are downgraded to the normal human prompt.
+- my-pi's maintained pi-permission-system keeps every `path` request inside the delegation envelope. For `external_directory`, built-in read-only path tools (`read`, `find`, `grep`, `ls`) may accept an auto-review `allow`; write, edit, bash, unknown tools, and undetermined surfaces are downgraded to the normal human prompt.
 
 ### Diagnostics
 
diff --git a/pi-permission-system/README.md b/pi-permission-system/README.md
index d892454..51e6daf 100644
--- a/pi-permission-system/README.md
+++ b/pi-permission-system/README.md
@@ -11,7 +11,7 @@ Permission enforcement extension for the [Pi](https://pi.mariozechner.at/) codin
 > **Fork notice:** This package is a full fork of [MasuRii/pi-permission-system](https://github.com/MasuRii/pi-permission-system), published to npm as `@gotgenes/pi-permission-system`.
 > It has diverged substantially from upstream in config format, internal architecture, and permission model.
 >
-> **my-pi maintenance note:** This directory was imported from upstream tag `pi-permission-system-v26.2.1` at commit `ec4fdb11343dc94f7185b113e559a4cf9f8dc035`. It is loaded from source and maintained directly by my-pi; npm `dist` output is not used. The local delegation envelope accepts an authorizer `allow` for built-in `read` access to `external_directory`, while write, edit, bash, unknown tools, and all `path` asks still defer to human confirmation.
+> **my-pi maintenance note:** This directory was imported from upstream tag `pi-permission-system-v26.2.1` at commit `ec4fdb11343dc94f7185b113e559a4cf9f8dc035`. It is loaded from source and maintained directly by my-pi; npm `dist` output is not used. The local delegation envelope accepts an authorizer `allow` for built-in read-only path tools (`read`, `find`, `grep`, `ls`) accessing `external_directory`, while write, edit, bash, unknown tools, and all `path` asks still defer to human confirmation.
 
 ## What It Does
 
diff --git a/pi-permission-system/docs/architecture/architecture.md b/pi-permission-system/docs/architecture/architecture.md
index 8eecff2..3015705 100644
--- a/pi-permission-system/docs/architecture/architecture.md
+++ b/pi-permission-system/docs/architecture/architecture.md
@@ -856,7 +856,7 @@ src/
 │   ├── authorizer-chain.ts    `composeAuthorizerChain(links, terminal, query, log)` - folds non-terminal `NamedAuthorizer` links ahead of the context-selected terminal (`defer` → next link, `allow`/`deny` → decision stamped `decidedBy: {kind: "authorizer", name, verdict, reason}` at the point the loop breaks, so a link that deferred is not credited), injecting `query` and the review-log `log` into each link; zero links returns the terminal instance (identity)
 │   ├── decision-source.ts     `DecisionSource` discriminated union (`user | authorizer | rule | session_approval | yolo | infrastructure_read | unavailable | gate_error | forwarded`) + depth-bounded tolerant guard `asDecisionSource`. Constraint: each variant is self-contained (it repeats its own surface/pattern/origin/name/reason) because the forwarded response file carries no such columns to lean on; the recursive `forwarded` variant is read off disk, so its guard is depth-bounded and rejects an over-deep chain whole rather than truncating it
 │   ├── authorizer-registry.ts `AuthorizerRegistry` (+ `AuthorizerLookup`/`AuthorizerRegistrar` ISP interfaces) - name → link `authorize` map mirroring `ToolAccessExtractorRegistry`; one instance in `index.ts`, exposed cross-extension via `PermissionsService.registerAuthorizer`; throw-on-duplicate, identity-guarded disposer
-│   ├── delegation-envelope.ts `encloseInDelegationEnvelope(authorize)` + `DELEGATION_EXCLUDED_SURFACES` - the bounded-delegation checkpoint (ADR 0007 §5): caps a link's `allow` on `path`, undetermined surfaces, and `external_directory` except for the built-in `read` tool; deny/defer pass through
+│   ├── delegation-envelope.ts `encloseInDelegationEnvelope(authorize)` + `DELEGATION_EXCLUDED_SURFACES` - the bounded-delegation checkpoint (ADR 0007 §5): caps a link's `allow` on `path`, undetermined surfaces, and `external_directory` except for built-in read-only path tools (`read`, `find`, `grep`, `ls`); deny/defer pass through
 │   ├── local-user-authorizer.ts `LocalUserAuthorizer` class - `TerminalAuthorizer` for a session with UI and the single `permissions:ui_prompt` emit site: renders a forwarded ask's provenance as a non-degraded broadcast + `(Subagent)` title, then dispatches to the inline keybind dialog (TUI) or the `select`/`input` fallback
 │   ├── permission-dialog.ts   Dialog option semantics + `requestPermissionDecisionFromUi` (`select`/`input` fallback) + `PermissionPromptDecision` (whose `decidedBy` is required) and `UnattributedDecision` (the same minus it); the mode dispatch lives in `permission-prompt-component.ts`
 │   ├── permission-prompt-decision.ts Pure decision model (`reducePrompt` + `PromptModelConfig`/`PromptViewState`) for the inline keybind dialog - hotkey arming (double-press), step transitions, reason validation; no SDK/TUI imports
diff --git a/pi-permission-system/docs/configuration.md b/pi-permission-system/docs/configuration.md
index e6a0ab5..640504f 100644
--- a/pi-permission-system/docs/configuration.md
+++ b/pi-permission-system/docs/configuration.md
@@ -227,7 +227,7 @@ Three invariants govern the chain:
 3. **Registration alone grants no authority.**
    Installing a judge extension gives it nothing; a link decides nothing until you name it here (opt-in activation).
 
-The chain owner caps every link with a **bounded-delegation checkpoint**. The `path` surface is always excluded. On `external_directory`, my-pi permits an `allow` only for the built-in `read` tool; write, edit, bash, extension/unknown tools, and missing tool identity are downgraded to `defer`.
+The chain owner caps every link with a **bounded-delegation checkpoint**. The `path` surface is always excluded. On `external_directory`, my-pi permits an `allow` for the built-in read-only path tools (`read`, `find`, `grep`, `ls`); write, edit, bash, extension/unknown tools, and missing tool identity are downgraded to `defer`.
 Deny and defer are never capped.
 The gate surface remains authoritative: a `write` blocked by a `path` rule is capped even though the displayed tool name is `write`.
 This holds for an ask forwarded up from a subagent exactly as it does for a local one.
diff --git a/pi-permission-system/src/authority/delegation-envelope.ts b/pi-permission-system/src/authority/delegation-envelope.ts
index 17f73cf..6bce3f8 100644
--- a/pi-permission-system/src/authority/delegation-envelope.ts
+++ b/pi-permission-system/src/authority/delegation-envelope.ts
@@ -8,12 +8,14 @@
  * verdict — it never turns a `defer`/`deny` into an `allow`.
  *
  * The excluded set is the whole `path` surface plus `external_directory`, with
- * one bundle-maintained exception: the built-in `read` tool may accept a link's
- * `allow` for an external-directory ask. Mutating tools, bash, extension tools,
- * and unknown tools remain capped to the terminal human authority. A finer
- * secret-shaped-`path` exclusion remains deferred; `path` stays fully excluded.
+ * one bundle-maintained exception: built-in read-only path tools may accept a
+ * link's `allow` for an external-directory ask. Mutating tools, bash, extension
+ * tools, and unknown tools remain capped to the terminal human authority. A
+ * finer secret-shaped-`path` exclusion remains deferred; `path` stays fully
+ * excluded.
  */
 
+import { READ_ONLY_PATH_BEARING_TOOLS } from "#src/access-intent/path-surfaces";
 import type { Authorizer } from "./authorizer";
 import type { PromptPermissionDetails } from "./permission-prompter";
 
@@ -23,9 +25,6 @@ export const DELEGATION_EXCLUDED_SURFACES: ReadonlySet<string> = new Set([
   "path",
 ]);
 
-/** Read-only external-directory access explicitly delegable in my-pi. */
-const DELEGABLE_EXTERNAL_DIRECTORY_TOOLS: ReadonlySet<string> = new Set(["read"]);
-
 /**
  * Wrap a link's `authorize` so an `allow` on an excluded surface is capped to
  * `defer`. All other verdicts, and `allow`s on non-excluded surfaces, pass
@@ -47,8 +46,8 @@ export function encloseInDelegationEnvelope(
 /**
  * Whether an allow verdict exceeds the delegation envelope. The gate-computed
  * surface is authoritative. `path` remains fully excluded; external-directory
- * access is excluded unless it comes from the built-in `read` tool. Unknown
- * surfaces fail safe to the terminal authority.
+ * access is excluded unless it comes from a built-in read-only path tool.
+ * Unknown surfaces fail safe to the terminal authority.
  */
 function isExcludedSurface(details: PromptPermissionDetails): boolean {
   const surface = details.accessIntent?.surface ?? details.surface ?? undefined;
@@ -58,7 +57,7 @@ function isExcludedSurface(details: PromptPermissionDetails): boolean {
   if (surface === "external_directory") {
     return !(
       details.toolName !== undefined &&
-      DELEGABLE_EXTERNAL_DIRECTORY_TOOLS.has(details.toolName)
+      READ_ONLY_PATH_BEARING_TOOLS.has(details.toolName)
     );
   }
   return DELEGATION_EXCLUDED_SURFACES.has(surface);
diff --git a/pi-permission-system/test/authority/delegation-envelope.test.ts b/pi-permission-system/test/authority/delegation-envelope.test.ts
index fe9f725..5065c66 100644
--- a/pi-permission-system/test/authority/delegation-envelope.test.ts
+++ b/pi-permission-system/test/authority/delegation-envelope.test.ts
@@ -91,15 +91,20 @@ describe("encloseInDelegationEnvelope", () => {
       expect(verdict).toEqual({ kind: "allow" });
     });
 
-    it("keeps an allow on external_directory for the built-in read tool", async () => {
-      const enclosed = encloseInDelegationEnvelope(makeLink({ kind: "allow" }));
-      const verdict = await enclosed(
-        makeDetails("external_directory", undefined, "read"),
-        query,
-        log,
-      );
-      expect(verdict).toEqual({ kind: "allow" });
-    });
+    it.each(["read", "find", "grep", "ls"] as const)(
+      "keeps an allow on external_directory for the built-in read-only tool %s",
+      async (toolName) => {
+        const enclosed = encloseInDelegationEnvelope(
+          makeLink({ kind: "allow" }),
+        );
+        const verdict = await enclosed(
+          makeDetails("external_directory", undefined, toolName),
+          query,
+          log,
+        );
+        expect(verdict).toEqual({ kind: "allow" });
+      },
+    );
 
     it("never caps a deny, even on an excluded surface", async () => {
       const enclosed = encloseInDelegationEnvelope(