Bundle building-bb-apps as a built-in injected skill

apps/host-daemon/src/injected-skills.test.ts

@@ -166,6 +166,51 @@ describe("injected skill staging", () => {
     });
   });
 
+  it("stages built-in skill sources into the shared catalog", async () => {
+    const dataDir = await makeTempDir();
+    const bundledRoot = await makeTempDir();
+    const skillRootPath = await writeSkill({
+      rootPath: bundledRoot,
+      name: "building-bb-apps",
+    });
+
+    const staged = await stageInjectedSkillSources({
+      dataDir,
+      injectedSkillSources: [
+        {
+          sourceType: "builtin",
+          applicationId: null,
+          name: "building-bb-apps",
+          description: "Use building-bb-apps when host staging tests run.",
+          sourceRootPath: skillRootPath,
+          skillFilePath: path.join(skillRootPath, "SKILL.md"),
+        },
+      ],
+    });
+
+    const claudeRoot = staged.skillRoots.find(isClaudeCodeSkillRoot);
+    if (!claudeRoot) {
+      throw new Error("Expected Claude Code skill root");
+    }
+    expect(claudeRoot.skillNames).toEqual(["building-bb-apps"]);
+    await expect(
+      readFile(
+        path.join(claudeRoot.localPluginPath, "catalog.json"),
+        "utf8",
+      ).then((content) => JSON.parse(content)),
+    ).resolves.toMatchObject({
+      catalogHash: staged.catalogHash,
+      skills: [
+        {
+          applicationId: null,
+          name: "building-bb-apps",
+          sourceRootPath: skillRootPath,
+          sourceType: "builtin",
+        },
+      ],
+    });
+  });
+
   it("changes the catalog hash when skill content changes", async () => {
     const dataDir = await makeTempDir();
     const sourceRootPath = path.join(dataDir, "source-skills");

apps/server/package.json

@@ -4,7 +4,7 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "build": "node ../../scripts/build-node-entry.mjs src/index.ts dist/index.js --clean-dist --templates --external ./start-server.js --copy-dir ../../packages/db/drizzle dist/drizzle && node --import tsx scripts/copy-app-scaffold-template.ts && node ../../scripts/build-node-entry.mjs src/start-server.ts dist/start-server.js",
+    "build": "node ../../scripts/build-node-entry.mjs src/index.ts dist/index.js --clean-dist --templates --external ./start-server.js --copy-dir ../../packages/db/drizzle dist/drizzle && node --import tsx scripts/copy-app-scaffold-template.ts && node --import tsx scripts/copy-builtin-skills.ts && node ../../scripts/build-node-entry.mjs src/start-server.ts dist/start-server.js",
     "bench": "vitest bench --config vitest.config.ts",
     "build:app-scaffold-template": "node ./scripts/build-app-scaffold-template.mjs",
     "start": "node dist/index.js",

apps/server/scripts/copy-builtin-skills.ts

@@ -0,0 +1,22 @@
+import { rm } from "node:fs/promises";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+import {
+  BUILTIN_SKILLS_DIRECTORY_NAME,
+  copyBuiltinSkills,
+  resolveBuiltinSkillsRootPath,
+} from "../src/services/skills/builtin-skills-copy.js";
+
+// Build step: copies the built-in injected skills into dist so the bundled
+// server resolves them beside its dist entry points, mirroring the app
+// scaffold template copy.
+const scriptDir = path.dirname(fileURLToPath(import.meta.url));
+const targetPath = path.resolve(
+  scriptDir,
+  "../dist",
+  BUILTIN_SKILLS_DIRECTORY_NAME,
+);
+
+const skillsRootPath = resolveBuiltinSkillsRootPath();
+await rm(targetPath, { force: true, recursive: true });
+await copyBuiltinSkills({ skillsRootPath, targetPath });

apps/server/src/services/skills/builtin-skills-copy.ts

@@ -0,0 +1,72 @@
+import { cp } from "node:fs/promises";
+import { constants as fsConstants, existsSync } from "node:fs";
+import path from "node:path";
+import { fileURLToPath } from "node:url";
+
+/**
+ * Locates and copies the built-in skills that ship beside this module.
+ *
+ * This module is shared between the server runtime (built-in injected skill
+ * discovery in ./injected-skills.ts) and the build step that copies the
+ * skills into dist (scripts/copy-builtin-skills.ts, loaded with tsx before
+ * workspace packages are built). Keep it free of workspace and third-party
+ * imports.
+ */
+
+interface CopyBuiltinSkillsArgs {
+  skillsRootPath: string;
+  targetPath: string;
+}
+
+interface ResolveBuiltinSkillsRootPathArgs {
+  moduleDir: string;
+}
+
+export const BUILTIN_SKILLS_DIRECTORY_NAME = "builtin-skills";
+// Structural essential the server itself depends on. Skill content may change
+// without breaking root detection.
+const BUILTIN_SKILLS_SENTINEL_PATH = path.join(
+  "building-bb-apps",
+  "SKILL.md",
+);
+const BUILTIN_SKILLS_COPY_MODE = fsConstants.COPYFILE_FICLONE;
+const builtinSkillsModuleDir = path.dirname(fileURLToPath(import.meta.url));
+
+function hasBuiltinSkillsRoot(skillsRootPath: string): boolean {
+  return existsSync(path.join(skillsRootPath, BUILTIN_SKILLS_SENTINEL_PATH));
+}
+
+/**
+ * The built-in skills directory sits beside this module in both layouts:
+ * src/services/skills/ in the source tree, and dist/ in the bundled server
+ * (the build copies the skills to dist/builtin-skills and esbuild bundles
+ * this module into the dist entry points).
+ */
+export function resolveBuiltinSkillsRootPathForModuleDir(
+  args: ResolveBuiltinSkillsRootPathArgs,
+): string {
+  const skillsRootPath = path.resolve(
+    args.moduleDir,
+    BUILTIN_SKILLS_DIRECTORY_NAME,
+  );
+  if (!hasBuiltinSkillsRoot(skillsRootPath)) {
+    throw new Error(`Missing built-in skills at ${skillsRootPath}`);
+  }
+  return skillsRootPath;
+}
+
+export function resolveBuiltinSkillsRootPath(): string {
+  return resolveBuiltinSkillsRootPathForModuleDir({
+    moduleDir: builtinSkillsModuleDir,
+  });
+}
+
+export async function copyBuiltinSkills(
+  args: CopyBuiltinSkillsArgs,
+): Promise<void> {
+  await cp(args.skillsRootPath, args.targetPath, {
+    force: false,
+    mode: BUILTIN_SKILLS_COPY_MODE,
+    recursive: true,
+  });
+}