fix: handle SCAFFOLD_MANIFEST.yml (underscore) in downloaded release tarballs

lib/scaffold-create.js

@@ -90,7 +90,7 @@ const runCreate = async ({
     await runManifestFn({
       agentConfig,
       folder,
-      manifestPath: path.join(folder, "SCAFFOLD-MANIFEST.yml"),
+      manifestPath: path.join(folder, path.basename(paths.manifestPath)),
     });
 
     if (prompt != null) {

lib/scaffold-create.test.js

@@ -330,6 +330,39 @@ describe("runCreate", () => {
     });
   });
 
+  test("uses SCAFFOLD_MANIFEST.yml (underscore) manifest filename when resolver returns it", async () => {
+    // Simulates a GitHub tarball where the manifest file has underscores instead of hyphens
+    const underscoreScaffoldDir = path.join(tempDir, "underscore-scaffold");
+    await fs.ensureDir(underscoreScaffoldDir);
+    await fs.writeFile(
+      path.join(underscoreScaffoldDir, "SCAFFOLD_MANIFEST.yml"),
+      "steps: []\n",
+    );
+
+    const calls = /** @type {Array<{manifestPath?: string}>} */ ([]);
+    const trackingManifest = async (
+      /** @type {{manifestPath?: string}} */ { manifestPath },
+    ) => {
+      calls.push({ manifestPath });
+    };
+
+    await runCreate({
+      folder: projectDir,
+      resolveExtensionFn: async () => ({
+        manifestPath: path.join(underscoreScaffoldDir, "SCAFFOLD_MANIFEST.yml"),
+        downloaded: false,
+      }),
+      runManifestFn: trackingManifest,
+    });
+
+    assert({
+      given: "resolver returns a SCAFFOLD_MANIFEST.yml (underscore) path",
+      should: "pass the underscore manifest path to runManifest",
+      actual: calls[0]?.manifestPath,
+      expected: path.join(projectDir, "SCAFFOLD_MANIFEST.yml"),
+    });
+  });
+
   test("given --prompt with echo agent, invokes agent and returns success", async () => {
     const result = await runCreate({
       folder: projectDir,

lib/scaffold-resolver.js

@@ -251,6 +251,32 @@ const resolveFileUri = ({ uri }) => {
 
 const SCAFFOLD_DOWNLOAD_DIR = path.join(AIDD_HOME, "scaffold");
 
+// GitHub release tarballs may convert hyphens to underscores in filenames,
+// so SCAFFOLD-MANIFEST.yml can arrive as SCAFFOLD_MANIFEST.yml.
+// This list is checked in priority order: the hyphen form is canonical.
+const SCAFFOLD_MANIFEST_NAMES = [
+  "SCAFFOLD-MANIFEST.yml",
+  "SCAFFOLD_MANIFEST.yml",
+];
+
+/**
+ * Resolves the manifest path within a directory, checking both the canonical
+ * hyphen form and the underscore form that GitHub tarballs may produce.
+ * Returns the path to the first existing variant, or the canonical path as a
+ * fallback (so callers receive a meaningful path in error messages).
+ * @param {string} dir
+ */
+const resolveManifestPath = async (dir) => {
+  for (const name of SCAFFOLD_MANIFEST_NAMES) {
+    const manifestPath = path.join(dir, name);
+    if (await fs.pathExists(manifestPath)) {
+      return manifestPath;
+    }
+  }
+  // Fallback: return canonical name so error messages are informative
+  return path.join(dir, SCAFFOLD_MANIFEST_NAMES[0]);
+};
+
 /**
  * @param {{uri: string, scaffoldDownloadDir?: string, download: Function}} options
  */
@@ -268,7 +294,7 @@ const downloadExtension = async ({
   await fs.ensureDir(scaffoldDownloadDir);
   await download(uri, scaffoldDownloadDir);
   return {
-    manifestPath: path.join(scaffoldDownloadDir, "SCAFFOLD-MANIFEST.yml"),
+    manifestPath: await resolveManifestPath(scaffoldDownloadDir),
     readmePath: path.join(scaffoldDownloadDir, "README.md"),
   };
 };
@@ -417,5 +443,7 @@ export {
   defaultDownloadAndExtract,
   defaultResolveRelease,
   resolveExtension,
+  resolveManifestPath,
   SCAFFOLD_DOWNLOAD_DIR,
+  SCAFFOLD_MANIFEST_NAMES,
 };

lib/scaffold-resolver.test.js

@@ -1041,6 +1041,78 @@ describe("resolveExtension - manifest existence validation", () => {
   });
 });
 
+describe("resolveExtension - SCAFFOLD_MANIFEST.yml (underscore) fallback", () => {
+  /** @type {string} */
+  let tempDir;
+
+  beforeEach(async () => {
+    tempDir = path.join(os.tmpdir(), `aidd-underscore-manifest-${Date.now()}`);
+    await fs.ensureDir(tempDir);
+  });
+
+  afterEach(async () => {
+    await fs.remove(tempDir);
+  });
+
+  test("resolves SCAFFOLD_MANIFEST.yml when SCAFFOLD-MANIFEST.yml is absent (HTTP download)", async () => {
+    // Simulates a GitHub tarball that produced SCAFFOLD_MANIFEST.yml instead of SCAFFOLD-MANIFEST.yml
+    // @ts-expect-error
+    const downloadWithUnderscore = async (_url, destPath) => {
+      await fs.ensureDir(destPath);
+      await fs.writeFile(
+        path.join(destPath, "SCAFFOLD_MANIFEST.yml"),
+        "steps:\n  - run: echo hello\n",
+      );
+    };
+
+    const paths = await resolveExtension({
+      type: "https://example.com/scaffold.tar.gz",
+      scaffoldDownloadDir: path.join(tempDir, "scaffold"),
+      confirm: noConfirm,
+      download: downloadWithUnderscore,
+      log: noLog,
+    });
+
+    assert({
+      given: "a downloaded scaffold with SCAFFOLD_MANIFEST.yml (underscore)",
+      should: "resolve without error and return the underscore manifest path",
+      actual: paths.manifestPath.endsWith("SCAFFOLD_MANIFEST.yml"),
+      expected: true,
+    });
+  });
+
+  test("prefers SCAFFOLD-MANIFEST.yml (hyphen) over SCAFFOLD_MANIFEST.yml (underscore) when both exist", async () => {
+    // @ts-expect-error
+    const downloadWithBoth = async (_url, destPath) => {
+      await fs.ensureDir(destPath);
+      await fs.writeFile(
+        path.join(destPath, "SCAFFOLD-MANIFEST.yml"),
+        "steps:\n  - run: echo hyphen\n",
+      );
+      await fs.writeFile(
+        path.join(destPath, "SCAFFOLD_MANIFEST.yml"),
+        "steps:\n  - run: echo underscore\n",
+      );
+    };
+
+    const paths = await resolveExtension({
+      type: "https://example.com/scaffold.tar.gz",
+      scaffoldDownloadDir: path.join(tempDir, "scaffold"),
+      confirm: noConfirm,
+      download: downloadWithBoth,
+      log: noLog,
+    });
+
+    assert({
+      given:
+        "a downloaded scaffold with both SCAFFOLD-MANIFEST.yml and SCAFFOLD_MANIFEST.yml",
+      should: "prefer the canonical hyphen form",
+      actual: paths.manifestPath.endsWith("SCAFFOLD-MANIFEST.yml"),
+      expected: true,
+    });
+  });
+});
+
 describe("defaultResolveRelease - GITHUB_TOKEN auth and error messages", () => {
   /** @type {any} */
   let originalFetch;