fix(codex): block unsupported execute worktrees

tests/bug-3360-codex-execute-phase-worktrees.test.cjs

@@ -0,0 +1,68 @@
+/**
+ * Regression test for bug #3360.
+ *
+ * Codex does not have a direct equivalent of Claude Code's
+ * `Agent(... isolation="worktree")`. The execute-phase workflow must fail
+ * closed for Codex + workflow.use_worktrees=true instead of spawning
+ * workspace-write executors in the main checkout.
+ */
+
+'use strict';
+
+process.env.GSD_TEST_MODE = '1';
+
+const { describe, test } = require('node:test');
+const assert = require('node:assert/strict');
+const fs = require('node:fs');
+const path = require('node:path');
+
+const ROOT = path.join(__dirname, '..');
+const EXECUTE_PHASE = path.join(ROOT, 'get-shit-done', 'workflows', 'execute-phase.md');
+const { getCodexSkillAdapterHeader } = require('../bin/install.js');
+
+function parseWorkflowSteps(content) {
+  return [...content.matchAll(/<step name="([^"]+)"[^>]*>([\s\S]*?)<\/step>/g)]
+    .map((match) => {
+      const body = match[2];
+      return {
+        name: match[1],
+        readsRuntimeConfig: body.includes('RUNTIME=$(gsd-sdk query config-get runtime --default claude'),
+        codexWorktreeGuard: body.includes('Codex execute-phase worktree isolation is unsupported'),
+        worktreeDispatchGuidance: body.includes('isolation="worktree"'),
+      };
+    });
+}
+
+function executePhaseWorktreeContract(content) {
+  const steps = parseWorkflowSteps(content);
+  const initializeIndex = steps.findIndex((step) => step.name === 'initialize');
+  const firstWorktreeDispatchIndex = steps.findIndex((step) => step.worktreeDispatchGuidance);
+  assert.notEqual(initializeIndex, -1, 'workflow must have an initialize step');
+  assert.notEqual(firstWorktreeDispatchIndex, -1, 'workflow must still document worktree dispatch guidance');
+
+  const initialize = steps[initializeIndex];
+  return {
+    initializeReadsRuntimeConfig: initialize.readsRuntimeConfig,
+    initializeHasCodexWorktreeGuard: initialize.codexWorktreeGuard,
+    guardStepPrecedesWorktreeDispatch: initializeIndex <= firstWorktreeDispatchIndex,
+  };
+}
+
+describe('#3360 — Codex execute-phase fails closed for unsupported worktree isolation', () => {
+  test('execute-phase reads runtime before worktree dispatch and blocks Codex worktree mode', () => {
+    const workflow = fs.readFileSync(EXECUTE_PHASE, 'utf8');
+    const contract = executePhaseWorktreeContract(workflow);
+
+    assert.deepEqual(contract, {
+      initializeReadsRuntimeConfig: true,
+      initializeHasCodexWorktreeGuard: true,
+      guardStepPrecedesWorktreeDispatch: true,
+    });
+  });
+
+  test('Codex adapter documents that worktree isolation has no direct spawn_agent mapping', () => {
+    const header = getCodexSkillAdapterHeader('gsd-execute-phase');
+    assert.match(header, /isolation="worktree"/);
+    assert.match(header, /no direct Codex mapping/i);
+  });
+});