fix(relink): skill_prefix patches the gbrain render too — the file the host actually serves (#2738)

gstack-relink linked SKILL.md from RENDER_DIR when a gbrain render was active
but ran gstack-patch-names only on INSTALL_DIR, so the served frontmatter kept
the unprefixed name and skill_prefix=true silently no-oped for every
brain-aware skill. The render tree (user-owned, untracked) is now patched too;
gstack-patch-names is idempotent so repeat relinks never double-prefix. The
gen-skill-docs note that pointed users at relink now describes what relink
actually covers.

Receipt: the new test fails on a v1.77.0.0 scratch worktree (served render
keeps 'name: qa').

Fixes #2738

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

bin/gstack-relink

@@ -110,8 +110,14 @@ for skill_dir in "$INSTALL_DIR"/*/; do
   SKILL_COUNT=$((SKILL_COUNT + 1))
 done
 
-# Patch SKILL.md name: fields to match prefix setting
+# Patch SKILL.md name: fields to match prefix setting. When a gbrain render
+# is active the loop above links SKILL.md from RENDER_DIR — the file the host
+# actually serves — so patch THAT tree too or skill_prefix=true is a no-op
+# for every brain-aware skill (#2738). gstack-patch-names takes an arbitrary
+# root, skips already-prefixed names (idempotent), and the render dir is
+# user-owned and untracked, so patching it never dirties a checkout.
 "$INSTALL_DIR/bin/gstack-patch-names" "$INSTALL_DIR" "$PREFIX"
+[ -d "$RENDER_DIR" ] && "$INSTALL_DIR/bin/gstack-patch-names" "$RENDER_DIR" "$PREFIX"
 
 if [ "$PREFIX" = "true" ]; then
   echo "Relinked $SKILL_COUNT skills as gstack-*"

scripts/gen-skill-docs.ts

@@ -1146,7 +1146,7 @@ if (!DRY_RUN) {
     if (fs.existsSync(configPath)) {
       const config = fs.readFileSync(configPath, 'utf-8');
       if (/^skill_prefix:\s*true/m.test(config)) {
-        console.log('\nNote: skill_prefix is true. Run gstack-relink to re-apply name: patches.');
+        console.log('\nNote: skill_prefix is true. Run gstack-relink to re-apply name: patches (it patches both the install and any active gbrain render).');
       }
     }
   } catch { /* non-fatal */ }

test/relink.test.ts

@@ -298,6 +298,44 @@ describe('gstack-relink (#578)', () => {
     );
   });
 
+  // #2738: with skill_prefix=true AND an active gbrain render, the symlink
+  // target is the RENDER copy — so the render's `name:` must get the gstack-
+  // prefix too, or the served frontmatter stays unprefixed and skill_prefix
+  // silently no-ops for every brain-aware skill.
+  test('skill_prefix=true patches the rendered SKILL.md name too (#2738)', () => {
+    setupMockInstall(['qa']);
+    const renderDir = path.join(tmpDir, 'render', 'claude', 'qa');
+    fs.mkdirSync(renderDir, { recursive: true });
+    fs.writeFileSync(
+      path.join(renderDir, 'SKILL.md'),
+      '---\nname: qa\ndescription: test\n---\nrendered brain-aware qa',
+    );
+
+    run(`${path.join(installDir, 'bin', 'gstack-config')} set skill_prefix true`, {
+      GSTACK_INSTALL_DIR: installDir,
+      GSTACK_SKILLS_DIR: skillsDir,
+      GSTACK_HOME: tmpDir,
+    });
+    run(`${path.join(installDir, 'bin', 'gstack-relink')}`, {
+      GSTACK_INSTALL_DIR: installDir,
+      GSTACK_SKILLS_DIR: skillsDir,
+      GSTACK_HOME: tmpDir,
+    });
+
+    const served = path.join(skillsDir, 'gstack-qa', 'SKILL.md');
+    expect(fs.readlinkSync(served)).toBe(path.join(renderDir, 'SKILL.md'));
+    // The SERVED file (the render) carries the prefixed name.
+    expect(fs.readFileSync(served, 'utf-8')).toContain('name: gstack-qa');
+    // Idempotent: a second relink must not double-prefix.
+    run(`${path.join(installDir, 'bin', 'gstack-relink')}`, {
+      GSTACK_INSTALL_DIR: installDir,
+      GSTACK_SKILLS_DIR: skillsDir,
+      GSTACK_HOME: tmpDir,
+    });
+    expect(fs.readFileSync(served, 'utf-8')).toContain('name: gstack-qa');
+    expect(fs.readFileSync(served, 'utf-8')).not.toContain('gstack-gstack-');
+  });
+
   // FIRST INSTALL: --no-prefix must create ONLY flat names, zero gstack-* pollution
   test('first install --no-prefix: only flat names exist, zero gstack-* entries', () => {
     setupMockInstall(['qa', 'ship', 'review', 'plan-ceo-review', 'gstack-upgrade']);