diff --git a/scripts/gen-skill-docs.ts b/scripts/gen-skill-docs.ts
index b08428b13..99a5f542c 100644
--- a/scripts/gen-skill-docs.ts
+++ b/scripts/gen-skill-docs.ts
@@ -817,7 +817,7 @@ function processExternalHost(
   const claudePath = ctx.tmplPath.replace(/\.tmpl$/, '');
   try {
     const resolvedClaude = fs.realpathSync(claudePath);
-    const resolvedExternal = fs.realpathSync(path.dirname(outputPath)) + '/' + path.basename(outputPath);
+    const resolvedExternal = path.join(fs.realpathSync(path.dirname(outputPath)), path.basename(outputPath));
     if (resolvedClaude === resolvedExternal) {
       symlinkLoop = true;
     }
diff --git a/test/claude-code-runner.test.ts b/test/claude-code-runner.test.ts
index d522ec3d9..5e0c3102f 100644
--- a/test/claude-code-runner.test.ts
+++ b/test/claude-code-runner.test.ts
@@ -30,7 +30,10 @@ writeFileSync(process.env.CAPTURE!, JSON.stringify({args:process.argv.slice(2),p
 const mode = process.env.FAKE_MODE;
 if (mode === 'timeout' || mode === 'descendant' || mode === 'escaped') {
   rmSync(process.env.PID_FILE!, { force: true });
-  const child = spawn(process.execPath, [process.env.DESCENDANT!], {stdio:['ignore','inherit','inherit'], detached:mode === 'escaped'});
+  // libuv on Windows kills non-detached children when this fake exits. The
+  // drain fixture must survive that exit so its inherited pipes remain open.
+  const child = spawn(process.execPath, [process.env.DESCENDANT!], {stdio:['ignore','inherit','inherit'],
+    detached:mode === 'escaped' || (process.platform === 'win32' && mode === 'descendant')});
   const readyBy = Date.now() + 2000;
   while (!existsSync(process.env.PID_FILE!)) {
     if (child.exitCode !== null || Date.now() >= readyBy) throw new Error('Descendant did not initialize its inherited pipes');
diff --git a/test/claude-code-windows-job.test.ts b/test/claude-code-windows-job.test.ts
index 224aa098e..0307264da 100644
--- a/test/claude-code-windows-job.test.ts
+++ b/test/claude-code-windows-job.test.ts
@@ -38,6 +38,10 @@ await Bun.stdin.text();
 rmSync(process.env.PID_FILE!, { force: true });
 const child = spawn(process.execPath, [process.env.DESCENDANT!], {
   stdio: ['ignore', 'inherit', 'inherit'],
+  // Bypass this fake's libuv auto-kill job so the pipe holder survives it.
+  // DETACHED does not request CREATE_BREAKAWAY_FROM_JOB: gstack's enclosing
+  // job still owns the descendant, which the assertions below require dead.
+  detached: process.platform === 'win32' && process.env.FAKE_MODE === 'descendant',
 });
 const readyBy = Date.now() + 2000;
 while (!existsSync(process.env.PID_FILE!)) {
diff --git a/test/gen-skill-docs-idempotency.test.ts b/test/gen-skill-docs-idempotency.test.ts
index a30b08dc9..f3390563b 100644
--- a/test/gen-skill-docs-idempotency.test.ts
+++ b/test/gen-skill-docs-idempotency.test.ts
@@ -150,7 +150,6 @@ describe('gen-skill-docs idempotency', () => {
       stdio: ['ignore', 'pipe', 'pipe'],
       timeout: 60_000,
     });
-    expect(result.status).toBe(0);
     const stdout = result.stdout?.toString() ?? '';
     // STALE: prefix means a file would change. Count them.
     const staleLines = stdout.split('\n').filter(l => l.startsWith('STALE:'));
@@ -161,6 +160,10 @@ describe('gen-skill-docs idempotency', () => {
         `\nRun \`bun run gen:skill-docs\` and commit the result.`,
       );
     }
+    // Report freshness diagnostics before asserting the exit code, so a CI
+    // failure identifies the stale file or subprocess error that caused it.
+    expect({ status: result.status, signal: result.signal, error: result.error?.message,
+      stderr: result.stderr?.toString() ?? '' }, stdout).toMatchObject({ status: 0, signal: null, error: undefined });
   }, 90_000);
 
   test('--host all idempotency: every host output is byte-stable across two runs', () => {
diff --git a/test/gen-skill-docs-prune-stale.test.ts b/test/gen-skill-docs-prune-stale.test.ts
index 68c3f2077..64d25ca3e 100644
--- a/test/gen-skill-docs-prune-stale.test.ts
+++ b/test/gen-skill-docs-prune-stale.test.ts
@@ -34,6 +34,25 @@ function gen(out: string, ...extra: string[]) {
 describe('gen-skill-docs stale-render prune', () => {
   test('a gstack-* render for a skill that no longer exists is removed; the sidecar symlink, real skills, un-bannered gstack-* dirs, and other hosts\' trees stay', () => {
     const out = fs.mkdtempSync(path.join(os.tmpdir(), 'gstack-prune-'));
+    // Keep the sidecar's source disposable: a broken symlink-loop guard must
+    // never overwrite this checkout's SKILL.md and poison parallel readers.
+    const source = path.join(out, 'source');
+    fs.mkdirSync(path.join(source, 'scripts'), { recursive: true });
+    fs.copyFileSync(path.join(ROOT, 'scripts', 'gen-skill-docs.ts'), path.join(source, 'scripts', 'gen-skill-docs.ts'));
+    for (const file of ['discover-skills.ts', 'gen-llms-txt.ts', 'gen-agents-digest.ts', 'models.ts']) {
+      fs.symlinkSync(path.join(ROOT, 'scripts', file), path.join(source, 'scripts', file), 'file');
+    }
+    fs.symlinkSync(path.join(ROOT, 'scripts', 'resolvers'), path.join(source, 'scripts', 'resolvers'), 'dir');
+    for (const dir of ['hosts', 'lib']) fs.symlinkSync(path.join(ROOT, dir), path.join(source, dir), 'dir');
+    for (const skill of ['', 'ship']) {
+      fs.mkdirSync(path.join(source, skill), { recursive: true });
+      fs.writeFileSync(path.join(source, skill, 'SKILL.md.tmpl'), `---\nname: ${skill || 'gstack'}\ndescription: Fixture skill.\n---\nFixture body.\n`);
+    }
+    const canonical = path.join(source, 'SKILL.md');
+    const metadata = path.join(source, 'agents', 'openai.yaml');
+    fs.mkdirSync(path.dirname(metadata), { recursive: true });
+    fs.writeFileSync(canonical, 'canonical skill sentinel\n');
+    fs.writeFileSync(metadata, 'canonical metadata sentinel\n');
     const skills = path.join(out, '.agents', 'skills');
     fs.mkdirSync(path.join(skills, 'gstack-retired-zzz'), { recursive: true });
     fs.writeFileSync(path.join(skills, 'gstack-retired-zzz', 'SKILL.md'), staleRender('gstack-retired-zzz', 'stale'));
@@ -47,15 +66,23 @@ describe('gen-skill-docs stale-render prune', () => {
     fs.mkdirSync(path.join(skills, 'gstack-lookalike'), { recursive: true });
     fs.writeFileSync(path.join(skills, 'gstack-lookalike', 'SKILL.md'), '---\nname: gstack-lookalike\n---\n<!-- auto-generated by someone else — do not edit -->\nmine\n');
     fs.mkdirSync(path.join(skills, 'not-ours'), { recursive: true });
-    fs.symlinkSync(ROOT, path.join(skills, 'gstack'));
+    fs.symlinkSync(source, path.join(skills, 'gstack'), 'dir');
     // Host isolation: a bannered stale-looking render under ANOTHER host's tree
     // in the same out-dir is not a codex run's to prune (or to touch at all).
     const factorySkills = path.join(out, '.factory', 'skills');
     fs.mkdirSync(path.join(factorySkills, 'gstack-zzz'), { recursive: true });
     fs.writeFileSync(path.join(factorySkills, 'gstack-zzz', 'SKILL.md'), staleRender('gstack-zzz', 'stale factory'));
     try {
-      const r = gen(out);
-      expect(r.status).toBe(0);
+      const r = spawnSync('bun', ['run', path.join(source, 'scripts', 'gen-skill-docs.ts'), '--host', 'codex', '--out-dir', out], {
+        cwd: source, encoding: 'utf-8', timeout: 180_000,
+        env: { ...process.env, GSTACK_DEFER_CLAUDE_RENAME_PRUNE: '0' },
+      });
+      expect(r.status, r.stderr).toBe(0);
+      // On Windows the old realpath + '/' comparison missed this alias,
+      // rewriting BOTH source artifacts through the sidecar.
+      expect(r.stdout.replace(/\\/g, '/')).toContain('SKIPPED (symlink loop): .agents/skills/gstack/SKILL.md');
+      expect(fs.readFileSync(canonical, 'utf-8')).toBe('canonical skill sentinel\n');
+      expect(fs.readFileSync(metadata, 'utf-8')).toBe('canonical metadata sentinel\n');
       expect(r.stdout).toContain('pruned stale codex render: gstack-retired-zzz');
       expect(fs.existsSync(path.join(skills, 'gstack-retired-zzz'))).toBe(false);
       // Exactly one prune in this run: the bannered stale render and nothing else.