feat(backend): upgrade Pi to 0.99.1 and load codemode, tool_search and MCP

apps/desktop/electron.vite.config.ts

@@ -25,6 +25,25 @@ const photonWasmPath = requireFromPi.resolve(
   "@silvia-odwyer/photon-node/photon_rs_bg.wasm",
 );
 
+// Pi's config.js is the anchor for codemode's bundled runtime: the emitted
+// codemode-worker.js and quickjs.wasm resolve relative to whichever chunk ends
+// up containing it, so both the transform and the guard below key off its id.
+const piConfigModuleId = realpathSync(join(piPackageDirectory, "dist/config.js"));
+const piCodemodeWorkerEntry = join(
+  piPackageDirectory,
+  "dist/extensions/codemode/worker.js",
+);
+// quickjs-wasi is a dependency of pi-codemode, not pi-coding-agent, so resolve
+// the wasm through pi-codemode's own package the way its imports do: pi's deps
+// sit beside it in the same scope directory (bun isolated install), which is
+// also where Node's upward node_modules walk finds it.
+const piCodemodeDirectory = realpathSync(
+  join(dirname(piPackageDirectory), "pi-codemode"),
+);
+const quickJsWasmPath = createRequire(
+  join(piCodemodeDirectory, "package.json"),
+).resolve("quickjs-wasi/quickjs.wasm");
+
 function copyMainRuntimeAssets(): Plugin {
   return {
     name: "pigui-copy-main-runtime-assets",
@@ -38,6 +57,12 @@ function copyMainRuntimeAssets(): Plugin {
 
       await mkdir(dirname(outputPath), { recursive: true });
       await copyFile(photonWasmPath, outputPath);
+      // Codemode's QuickJS runtime is looked up beside the chunk that contains
+      // pi's dist/config.js (see rewritePiQuickJsWasmResolution).
+      await copyFile(
+        quickJsWasmPath,
+        resolve(options.dir, "chunks/quickjs.wasm"),
+      );
       // Pi resolves built-in themes through its public package asset directory.
       const themes = "dist/modes/interactive/theme";
       const themeDirectory = resolve(options.dir, "pi-assets", themes);
@@ -67,6 +92,66 @@ const __dirname = import.meta.dirname;
 const require = __cjs_mod__.createRequire(import.meta.url);
 `;
 
+// Pi's dist/config.js resolves the codemode QuickJS wasm through createRequire,
+// which cannot work in the packaged app: electron-builder ships no node_modules.
+// Point it at the copy emitted beside the chunk instead. The replacement must
+// match exactly once so a Pi upgrade that rewrites this lookup fails the build
+// loudly instead of silently breaking codemode.
+const QUICKJS_WASM_REQUIRE =
+  'createRequire(import.meta.url).resolve("quickjs-wasi/quickjs.wasm")';
+
+function rewritePiQuickJsWasmResolution(): Plugin {
+  return {
+    name: "pigui-pi-quickjs-wasm-path",
+    apply: "build",
+    transform(code, id) {
+      if (id !== piConfigModuleId) {
+        return null;
+      }
+      const occurrences = code.split(QUICKJS_WASM_REQUIRE).length - 1;
+      if (occurrences !== 1) {
+        throw new Error(
+          `Expected exactly one "${QUICKJS_WASM_REQUIRE}" in ${id}, found ${occurrences}.`,
+        );
+      }
+      return {
+        code:
+          'import { fileURLToPath as __paceFileURLToPath } from "node:url";\n' +
+          code.replace(
+            QUICKJS_WASM_REQUIRE,
+            '__paceFileURLToPath(new URL("./quickjs.wasm", import.meta.url))',
+          ),
+        map: null,
+      };
+    },
+  };
+}
+
+// getCodemodeWorkerUrl() and the wasm lookup above both resolve relative to the
+// emitted chunk that contains pi's dist/config.js. If chunk splitting ever moves
+// it out of chunks/, both files land in the wrong place — fail the build.
+function assertPiConfigChunkLocation(): Plugin {
+  return {
+    name: "pigui-pi-config-chunk-location",
+    apply: "build",
+    generateBundle(_options, bundle) {
+      const chunk = Object.values(bundle).find(
+        (output) =>
+          output.type === "chunk" && output.moduleIds.includes(piConfigModuleId),
+      );
+      if (!chunk) {
+        throw new Error("No emitted main chunk contains pi's dist/config.js.");
+      }
+      if (!chunk.fileName.startsWith("chunks/")) {
+        throw new Error(
+          `Pi's dist/config.js must stay under chunks/ (emitted as ${chunk.fileName}); ` +
+            "codemode-worker.js and quickjs.wasm resolve relative to it.",
+        );
+      }
+    },
+  };
+}
+
 function hoistCommonJsShim(): Plugin {
   return {
     name: "pigui-hoist-cjs-shim",
@@ -86,6 +171,9 @@ const mainBuild = {
       main: resolve(__dirname, "electron/main.ts"),
       backend: resolve(__dirname, "electron/backend.ts"),
       "session-worker": resolve(__dirname, "electron/session-worker.ts"),
+      // Pi's bundled codemode entry; getCodemodeWorkerUrl() resolves
+      // ./codemode-worker.js beside the chunk containing dist/config.js.
+      "chunks/codemode-worker": piCodemodeWorkerEntry,
     },
     output: {
       entryFileNames: "[name].js",
@@ -148,6 +236,8 @@ export default defineConfig({
     plugins: [
       externalizeDepsPlugin({ exclude: [...internalPackages, "electron-updater"] }),
       copyMainRuntimeAssets(),
+      rewritePiQuickJsWasmResolution(),
+      assertPiConfigChunkLocation(),
       hoistCommonJsShim(),
     ],
     build: mainBuild as any,

docs/adr/0046-load-pi-builtin-extensions.md

@@ -0,0 +1,29 @@
+# ADR-0046：在 SDK 会话中加载 Pi 内建扩展
+
+- 状态：Accepted
+- 日期：2026-09-30
+- 来源：Pi 0.99 升级
+
+## 背景
+
+Pi 0.99 新增了 codemode、tool_search、MCP 三项能力，形态是 CLI 内建扩展：`pi` 二进制在启动时以 `{ name, factory, replaceable: true, builtin: true }` 的形式注册它们，但 SDK 会话（`createAgentSession` / `DefaultResourceLoader`）不会自动加载。Pace 每个 root Session 都跑在独立进程里嵌 Pi SDK（`SessionProcessDriver` + `pi-sdk-driver`，ADR-0040/0041），不补上这三个工厂，Pace 会话里就没有 codemode、`/mcp`、tool_search，`mcp.json` 里配置的服务器也不会连接。
+
+Pi 同时改了打包形态：codemode 的脚本在 QuickJS WASM VM 里跑（`quickjs-wasi`），执行发生在独立 worker 线程里。`dist/config.js` 用 `createRequire(import.meta.url).resolve("quickjs-wasi/quickjs.wasm")` 找 wasm，并用 `new URL("./codemode-worker.js", import.meta.url)` 找打包构建里与 config 同 chunk 目录的 worker 入口（`dist/extensions/codemode/worker.js`，只做 `import "@earendil-works/pi-codemode/worker"`）。Pace 把 Pi SDK 打进 `apps/desktop/out/main`（electron-vite），打包产物里没有任何 node_modules，所以这两个相对资源都得由我们的构建产出。
+
+## 决策
+
+1. 新增 `packages/backend/src/drivers/pi-builtin-extensions.ts` 导出 `createPaceBuiltInExtensions(): InlineExtension[]`，按 CLI 的形状返回 codemode、tool-search、mcp 三条（各自 `replaceable: true, builtin: true`，工厂为无参 `createCodemodeExtension()` / `createToolSearchExtension()` / `createMcpExtension()`，让用户设置如 `codemode.mode` 生效）。两处构造 `DefaultResourceLoader` 的地方——`service.ts` 与 `session-process-entry.ts` 的 `sessionOptionsFor`——都传 `extensionFactories: createPaceBuiltInExtensions()`。`builtin: true` 让这些条目以 `builtin:<name>` 资源加载：默认启用、`settings.json` 里 `-builtin:<name>` 可禁用、`pi config` 可见；`replaceable: true` 让注册了同名 tool/command 的第三方扩展接管而不是报冲突，与 CLI 行为一致。llama.cpp 内建（`builtin:llama.cpp`）刻意先不加载。
+2. 打包（`apps/desktop/electron.vite.config.ts`）：
+   - main 构建新增 rollup input `chunks/codemode-worker` → Pi 包的 `dist/extensions/codemode/worker.js`，配合 `entryFileNames: "[name].js"` 产出 `out/main/chunks/codemode-worker.js`，正好落在 `getCodemodeWorkerUrl()` 的相对 URL 上。
+   - 一个 `transform` 插件对 pi 的 `dist/config.js`（按 realpath 匹配）把 `createRequire(import.meta.url).resolve("quickjs-wasi/quickjs.wasm")` 替换为相对同 chunk 的 `new URL("./quickjs.wasm", import.meta.url)`；目标文本必须恰好出现一次，否则构建报错，Pi 升级改动这段代码时会立刻暴露。
+   - `copyMainRuntimeAssets` 另外把 `quickjs.wasm`（经 pi-codemode 包解析，因为它是 pi-codemode 的依赖而非 pi-coding-agent 的）复制到 `chunks/quickjs.wasm`。
+   - `generateBundle` 里加守卫：找到包含 pi `dist/config.js` 的输出 chunk，若不在 `chunks/` 下则构建失败——两个相对 URL 都依赖这个位置。
+
+## 后果
+
+- Pace 会话恢复 codemode / tool_search / MCP，且 `-builtin:<name>` 禁用与第三方替换语义与 CLI 完全一致。
+- `scripts/test-bundled-runtime.mjs` 新增一条端到端断言：打出的 `out/main` 在无 node_modules、空 PATH 下跑通「模型发起 codemode 调用 → 脚本调用 `mcp__probe__echo` → 拿到回显」，回归覆盖 worker/wasm 的相对布局。
+- 已知缺口，留给后续 PR：
+  - MCP 扩展的状态与错误只经 `ctx.ui.notify` 上报，OAuth 登录要求 `ctx.hasUI`；Pace 的 `bindExtensions` 目前只传 `onError`，这些提示会被丢弃，`/mcp login` 在 Pace 里不可用（用户可在 shell 里跑 `pi mcp login`，凭据共享同一 agent dir）。
+  - 嵌套工具调用带 `parentToolCallId`，Pace 尚未投影，嵌套调用在 UI 上不呈现父子关系。
+  - llama.cpp 内建未加载。

packages/backend/package.json

@@ -12,8 +12,8 @@
     ".": "./src/index.ts"
   },
   "dependencies": {
-    "@earendil-works/pi-ai": "0.87.1",
-    "@earendil-works/pi-coding-agent": "0.87.1",
+    "@earendil-works/pi-ai": "0.99.1",
+    "@earendil-works/pi-coding-agent": "0.99.1",
     "@pace/core": "workspace:*"
   }
 }

packages/backend/src/drivers/pi-builtin-extensions.test.ts

@@ -0,0 +1,57 @@
+import { mkdtemp, rm, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import {
+  DefaultResourceLoader,
+  SettingsManager,
+} from "@earendil-works/pi-coding-agent";
+import { afterEach, describe, expect, it } from "vitest";
+import { createPaceBuiltInExtensions } from "./pi-builtin-extensions";
+
+const tempDirs: string[] = [];
+
+async function tempDir() {
+  const dir = await mkdtemp(join(tmpdir(), "pace-builtin-extensions-"));
+  tempDirs.push(dir);
+  return dir;
+}
+
+afterEach(async () => {
+  await Promise.all(
+    tempDirs.splice(0).map((dir) => rm(dir, { recursive: true, force: true })),
+  );
+});
+
+async function loadExtensionPaths(options?: { settings?: unknown }) {
+  const cwd = await tempDir();
+  const agentDir = await tempDir();
+  if (options?.settings !== undefined) {
+    await writeFile(join(agentDir, "settings.json"), JSON.stringify(options.settings));
+  }
+  const loader = new DefaultResourceLoader({
+    cwd,
+    agentDir,
+    settingsManager: SettingsManager.create(cwd, agentDir),
+    extensionFactories: createPaceBuiltInExtensions(),
+  });
+  await loader.reload();
+  return loader.getExtensions().extensions.map((extension) => extension.path);
+}
+
+describe("createPaceBuiltInExtensions", () => {
+  it("loads codemode, tool-search, and mcp as builtin extensions", async () => {
+    const paths = await loadExtensionPaths();
+    expect(paths).toContain("builtin:codemode");
+    expect(paths).toContain("builtin:tool-search");
+    expect(paths).toContain("builtin:mcp");
+  });
+
+  it("honors -builtin:<name> in the extensions setting", async () => {
+    const paths = await loadExtensionPaths({
+      settings: { extensions: ["-builtin:mcp"] },
+    });
+    expect(paths).not.toContain("builtin:mcp");
+    expect(paths).toContain("builtin:codemode");
+    expect(paths).toContain("builtin:tool-search");
+  });
+});