diff --git a/.gitignore b/.gitignore
index d8a457c..1b5c072 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,8 @@ dist/
 .wrangler/
 .dev.vars
 .mcp.json
+# cc-taskrunner worktree protection
+C:*
+node_modules/
+.pnpm-store/
+__pycache__/
diff --git a/test/scaffold-materializer.test.ts b/test/scaffold-materializer.test.ts
new file mode 100644
index 0000000..983bd58
--- /dev/null
+++ b/test/scaffold-materializer.test.ts
@@ -0,0 +1,103 @@
+import { describe, it, expect } from 'vitest';
+import { materializeScaffold } from '../src/scaffold-materializer.js';
+
+const facts = {
+  project_type: 'api',
+  complexity: 'standard',
+  requirement_name: 'User Profile',
+  requirement_element: 'User',
+  requirement_orientation: 'upright',
+  requirement_priority: 'P0',
+  requirement_effort: 'small',
+  requirement_acceptance:
+    'profile edits saved without full reload,avatar resized server-side,email change triggers verification',
+  interface_name: 'Stack',
+  interface_element: 'Flow',
+  interface_orientation: 'upright',
+  interface_regions: 'content',
+  interface_grid: '1fr',
+  threat_name: 'Authentication Bypass',
+  threat_element: 'Security',
+  threat_orientation: 'upright',
+  threat_likelihood: 'medium',
+  threat_impact: 'critical',
+  threat_mitigation: 'centralised auth middleware on every protected route',
+  runtime_name: 'Workers for Platforms',
+  runtime_element: 'Edge',
+  runtime_orientation: 'upright',
+  runtime_tier: 'blessed',
+  runtime_traits: ['multi-tenant', 'isolation', 'dispatch', 'user-scripts'],
+  test_plan_name: 'Mock Dependency Test',
+  test_plan_element: 'Isolation',
+  test_plan_orientation: 'reversed',
+  test_plan_framework: 'vitest',
+  test_plan_ci_stage: 'pre-commit',
+  test_plan_coverage_target: '90',
+  first_task_name: 'Search Feature',
+  first_task_element: 'Build',
+  first_task_orientation: 'upright',
+  first_task_estimate: '5',
+  first_task_complexity: 'medium',
+  first_task_deliverable:
+    'search input with debounce, filter panel, result list with count',
+  position_count: 6,
+  shadow_density: 0.17,
+  elemental_balance: { Fire: 0, Water: 0, Air: 0, Earth: 0, Spirit: 0 },
+  scaffold_confidence: 'high',
+};
+
+const intention = 'Build a user profile management API';
+
+describe('scaffold materializer', () => {
+  it('is deterministic — identical inputs produce identical outputs', () => {
+    const result1 = materializeScaffold(facts, intention);
+    const result2 = materializeScaffold(facts, intention);
+    expect(result1.files).toEqual(result2.files);
+    expect(result1.nextSteps).toEqual(result2.nextSteps);
+  });
+
+  it('generates exactly 9 files', () => {
+    const result = materializeScaffold(facts, intention);
+    expect(result.files).toHaveLength(9);
+  });
+
+  it('generates the expected file paths', () => {
+    const result = materializeScaffold(facts, intention);
+    const paths = result.files.map((f) => f.path);
+    expect(paths).toEqual([
+      '.ai/manifest.adf',
+      '.ai/core.adf',
+      '.ai/state.adf',
+      'package.json',
+      'tsconfig.json',
+      'wrangler.toml',
+      'src/index.ts',
+      'test/index.test.ts',
+      'README.md',
+    ]);
+  });
+
+  it('derives the project name and embeds it in package.json', () => {
+    const result = materializeScaffold(facts, intention);
+    const pkgFile = result.files.find((f) => f.path === 'package.json')!;
+    const pkg = JSON.parse(pkgFile.content);
+    // "Build a user profile management API" → strips "build", slugifies first 3 words
+    expect(pkg.name).toBe('a-user-profile');
+  });
+
+  it('detects Workers runtime and configures wrangler.toml + devDependencies', () => {
+    const result = materializeScaffold(facts, intention);
+
+    const wranglerFile = result.files.find((f) => f.path === 'wrangler.toml')!;
+    expect(wranglerFile.content).toContain('main = "src/index.ts"');
+
+    const pkgFile = result.files.find((f) => f.path === 'package.json')!;
+    const pkg = JSON.parse(pkgFile.content);
+    expect(pkg.devDependencies).toHaveProperty('wrangler');
+  });
+
+  it('handles empty facts without throwing', () => {
+    const result = materializeScaffold({}, '');
+    expect(Array.isArray(result.files)).toBe(true);
+  });
+});