diff --git a/src/__tests__/catalog.test.ts b/src/__tests__/catalog.test.ts
new file mode 100644
index 0000000..af9863b
--- /dev/null
+++ b/src/__tests__/catalog.test.ts
@@ -0,0 +1,373 @@
+/**
+ * Tests for facet catalog scanning and display.
+ */
+
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { mkdtempSync, writeFileSync, mkdirSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import {
+  extractDescription,
+  parseFacetType,
+  scanFacets,
+  displayFacets,
+  showCatalog,
+  type FacetEntry,
+} from '../features/catalog/catalogFacets.js';
+
+// Mock external dependencies to isolate unit tests
+vi.mock('../infra/config/global/globalConfig.js', () => ({
+  getLanguage: () => 'en',
+  getBuiltinPiecesEnabled: () => true,
+}));
+
+const mockLogError = vi.fn();
+const mockInfo = vi.fn();
+vi.mock('../shared/ui/index.js', () => ({
+  error: (...args: unknown[]) => mockLogError(...args),
+  info: (...args: unknown[]) => mockInfo(...args),
+  section: (title: string) => console.log(title),
+}));
+
+let mockBuiltinDir: string;
+vi.mock('../infra/resources/index.js', () => ({
+  getLanguageResourcesDir: () => mockBuiltinDir,
+}));
+
+let mockGlobalDir: string;
+vi.mock('../infra/config/paths.js', () => ({
+  getGlobalConfigDir: () => mockGlobalDir,
+  getProjectConfigDir: (cwd: string) => join(cwd, '.takt'),
+}));
+
+describe('parseFacetType', () => {
+  it('should return FacetType for valid inputs', () => {
+    expect(parseFacetType('personas')).toBe('personas');
+    expect(parseFacetType('policies')).toBe('policies');
+    expect(parseFacetType('knowledge')).toBe('knowledge');
+    expect(parseFacetType('instructions')).toBe('instructions');
+    expect(parseFacetType('output-contracts')).toBe('output-contracts');
+  });
+
+  it('should return null for invalid inputs', () => {
+    expect(parseFacetType('unknown')).toBeNull();
+    expect(parseFacetType('persona')).toBeNull();
+    expect(parseFacetType('')).toBeNull();
+  });
+});
+
+describe('extractDescription', () => {
+  let tempDir: string;
+
+  beforeEach(() => {
+    tempDir = mkdtempSync(join(tmpdir(), 'takt-catalog-test-'));
+  });
+
+  afterEach(() => {
+    rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('should extract first heading from markdown file', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, '# My Persona\n\nSome content here.');
+
+    expect(extractDescription(filePath)).toBe('My Persona');
+  });
+
+  it('should return first non-empty line when no heading exists', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, 'No heading in this file\nJust plain text.');
+
+    expect(extractDescription(filePath)).toBe('No heading in this file');
+  });
+
+  it('should return empty string when file is empty', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, '');
+
+    expect(extractDescription(filePath)).toBe('');
+  });
+
+  it('should skip blank lines and return first non-empty line', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, '\n\n  \nActual content here\nMore text.');
+
+    expect(extractDescription(filePath)).toBe('Actual content here');
+  });
+
+  it('should extract from first heading, ignoring later headings', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, 'Preamble\n# First Heading\n# Second Heading');
+
+    expect(extractDescription(filePath)).toBe('First Heading');
+  });
+
+  it('should trim whitespace from heading text', () => {
+    const filePath = join(tempDir, 'test.md');
+    writeFileSync(filePath, '#   Spaced Heading  \n');
+
+    expect(extractDescription(filePath)).toBe('Spaced Heading');
+  });
+});
+
+describe('scanFacets', () => {
+  let tempDir: string;
+  let builtinDir: string;
+  let globalDir: string;
+  let projectDir: string;
+
+  beforeEach(() => {
+    tempDir = mkdtempSync(join(tmpdir(), 'takt-catalog-test-'));
+    builtinDir = join(tempDir, 'builtin-lang');
+    globalDir = join(tempDir, 'global');
+    projectDir = join(tempDir, 'project');
+
+    mockBuiltinDir = builtinDir;
+    mockGlobalDir = globalDir;
+  });
+
+  afterEach(() => {
+    rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('should collect facets from all three layers', () => {
+    // Given: facets in builtin, user, and project layers
+    const builtinPersonas = join(builtinDir, 'personas');
+    const globalPersonas = join(globalDir, 'personas');
+    const projectPersonas = join(projectDir, '.takt', 'personas');
+    mkdirSync(builtinPersonas, { recursive: true });
+    mkdirSync(globalPersonas, { recursive: true });
+    mkdirSync(projectPersonas, { recursive: true });
+
+    writeFileSync(join(builtinPersonas, 'coder.md'), '# Coder Agent');
+    writeFileSync(join(globalPersonas, 'my-reviewer.md'), '# My Reviewer');
+    writeFileSync(join(projectPersonas, 'project-coder.md'), '# Project Coder');
+
+    // When: scanning personas
+    const entries = scanFacets('personas', projectDir);
+
+    // Then: all three entries are collected
+    expect(entries).toHaveLength(3);
+
+    const coder = entries.find((e) => e.name === 'coder');
+    expect(coder).toBeDefined();
+    expect(coder!.source).toBe('builtin');
+    expect(coder!.description).toBe('Coder Agent');
+
+    const myReviewer = entries.find((e) => e.name === 'my-reviewer');
+    expect(myReviewer).toBeDefined();
+    expect(myReviewer!.source).toBe('user');
+
+    const projectCoder = entries.find((e) => e.name === 'project-coder');
+    expect(projectCoder).toBeDefined();
+    expect(projectCoder!.source).toBe('project');
+  });
+
+  it('should detect override when higher layer has same name', () => {
+    // Given: same facet name in builtin and user layers
+    const builtinPersonas = join(builtinDir, 'personas');
+    const globalPersonas = join(globalDir, 'personas');
+    mkdirSync(builtinPersonas, { recursive: true });
+    mkdirSync(globalPersonas, { recursive: true });
+
+    writeFileSync(join(builtinPersonas, 'coder.md'), '# Builtin Coder');
+    writeFileSync(join(globalPersonas, 'coder.md'), '# Custom Coder');
+
+    // When: scanning personas
+    const entries = scanFacets('personas', tempDir);
+
+    // Then: builtin entry is marked as overridden by user
+    const builtinCoder = entries.find((e) => e.name === 'coder' && e.source === 'builtin');
+    expect(builtinCoder).toBeDefined();
+    expect(builtinCoder!.overriddenBy).toBe('user');
+
+    const userCoder = entries.find((e) => e.name === 'coder' && e.source === 'user');
+    expect(userCoder).toBeDefined();
+    expect(userCoder!.overriddenBy).toBeUndefined();
+  });
+
+  it('should detect override through project layer', () => {
+    // Given: same facet name in builtin and project layers
+    const builtinPolicies = join(builtinDir, 'policies');
+    const projectPolicies = join(projectDir, '.takt', 'policies');
+    mkdirSync(builtinPolicies, { recursive: true });
+    mkdirSync(projectPolicies, { recursive: true });
+
+    writeFileSync(join(builtinPolicies, 'coding.md'), '# Builtin Coding');
+    writeFileSync(join(projectPolicies, 'coding.md'), '# Project Coding');
+
+    // When: scanning policies
+    const entries = scanFacets('policies', projectDir);
+
+    // Then: builtin entry is marked as overridden by project
+    const builtinCoding = entries.find((e) => e.name === 'coding' && e.source === 'builtin');
+    expect(builtinCoding).toBeDefined();
+    expect(builtinCoding!.overriddenBy).toBe('project');
+  });
+
+  it('should handle non-existent directories gracefully', () => {
+    // Given: no directories exist
+    // When: scanning a facet type
+    const entries = scanFacets('knowledge', projectDir);
+
+    // Then: returns empty array
+    expect(entries).toEqual([]);
+  });
+
+  it('should only include .md files', () => {
+    // Given: directory with mixed file types
+    const builtinKnowledge = join(builtinDir, 'knowledge');
+    mkdirSync(builtinKnowledge, { recursive: true });
+
+    writeFileSync(join(builtinKnowledge, 'valid.md'), '# Valid');
+    writeFileSync(join(builtinKnowledge, 'ignored.txt'), 'Not a markdown');
+    writeFileSync(join(builtinKnowledge, 'also-ignored.yaml'), 'name: yaml');
+
+    // When: scanning knowledge
+    const entries = scanFacets('knowledge', tempDir);
+
+    // Then: only .md file is included
+    expect(entries).toHaveLength(1);
+    expect(entries[0]!.name).toBe('valid');
+  });
+
+  it('should work with all facet types', () => {
+    // Given: one facet in each type directory
+    const types = ['personas', 'policies', 'knowledge', 'instructions', 'output-contracts'] as const;
+    for (const type of types) {
+      const dir = join(builtinDir, type);
+      mkdirSync(dir, { recursive: true });
+      writeFileSync(join(dir, 'test.md'), `# Test ${type}`);
+    }
+
+    // When/Then: each type is scannable
+    for (const type of types) {
+      const entries = scanFacets(type, tempDir);
+      expect(entries).toHaveLength(1);
+      expect(entries[0]!.name).toBe('test');
+    }
+  });
+});
+
+describe('displayFacets', () => {
+  let consoleSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    consoleSpy.mockRestore();
+  });
+
+  it('should display entries with name, description, and source', () => {
+    // Given: a list of facet entries
+    const entries: FacetEntry[] = [
+      { name: 'coder', description: 'Coder Agent', source: 'builtin' },
+      { name: 'my-reviewer', description: 'My Reviewer', source: 'user' },
+    ];
+
+    // When: displaying facets
+    displayFacets('personas', entries);
+
+    // Then: output contains facet names
+    const output = consoleSpy.mock.calls.map((c) => c[0]).join('\n');
+    expect(output).toContain('coder');
+    expect(output).toContain('my-reviewer');
+    expect(output).toContain('Personas');
+  });
+
+  it('should display (none) when entries are empty', () => {
+    // Given: empty entries
+    const entries: FacetEntry[] = [];
+
+    // When: displaying facets
+    displayFacets('policies', entries);
+
+    // Then: output shows (none)
+    const output = consoleSpy.mock.calls.map((c) => c[0]).join('\n');
+    expect(output).toContain('(none)');
+  });
+
+  it('should display override information', () => {
+    // Given: an overridden entry
+    const entries: FacetEntry[] = [
+      { name: 'coder', description: 'Builtin Coder', source: 'builtin', overriddenBy: 'user' },
+    ];
+
+    // When: displaying facets
+    displayFacets('personas', entries);
+
+    // Then: output contains override info
+    const output = consoleSpy.mock.calls.map((c) => c[0]).join('\n');
+    expect(output).toContain('overridden by user');
+  });
+});
+
+describe('showCatalog', () => {
+  let tempDir: string;
+  let builtinDir: string;
+  let globalDir: string;
+  let consoleSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    tempDir = mkdtempSync(join(tmpdir(), 'takt-catalog-test-'));
+    builtinDir = join(tempDir, 'builtin-lang');
+    globalDir = join(tempDir, 'global');
+
+    mockBuiltinDir = builtinDir;
+    mockGlobalDir = globalDir;
+    mockLogError.mockClear();
+    mockInfo.mockClear();
+    consoleSpy = vi.spyOn(console, 'log').mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    consoleSpy.mockRestore();
+    rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('should display only the specified facet type when valid type is given', () => {
+    // Given: personas facet exists
+    const builtinPersonas = join(builtinDir, 'personas');
+    mkdirSync(builtinPersonas, { recursive: true });
+    writeFileSync(join(builtinPersonas, 'coder.md'), '# Coder Agent');
+
+    // When: showing catalog for personas only
+    showCatalog(tempDir, 'personas');
+
+    // Then: output contains the facet name and no error
+    const output = consoleSpy.mock.calls.map((c) => c[0]).join('\n');
+    expect(output).toContain('coder');
+    expect(mockLogError).not.toHaveBeenCalled();
+  });
+
+  it('should show error when invalid facet type is given', () => {
+    // When: showing catalog for an invalid type
+    showCatalog(tempDir, 'invalid-type');
+
+    // Then: error is logged with the invalid type name
+    expect(mockLogError).toHaveBeenCalledWith(
+      expect.stringContaining('invalid-type'),
+    );
+    // Then: available types are shown via info
+    expect(mockInfo).toHaveBeenCalledWith(
+      expect.stringContaining('personas'),
+    );
+  });
+
+  it('should display all five facet types when no type is specified', () => {
+    // Given: no facets exist (empty directories)
+
+    // When: showing catalog without specifying a type
+    showCatalog(tempDir);
+
+    // Then: all 5 facet type headings are displayed
+    const output = consoleSpy.mock.calls.map((c) => c[0]).join('\n');
+    expect(output).toContain('Personas');
+    expect(output).toContain('Policies');
+    expect(output).toContain('Knowledge');
+    expect(output).toContain('Instructions');
+    expect(output).toContain('Output-contracts');
+  });
+});
diff --git a/src/app/cli/commands.ts b/src/app/cli/commands.ts
index d176ac4..7566ffb 100644
--- a/src/app/cli/commands.ts
+++ b/src/app/cli/commands.ts
@@ -1,7 +1,7 @@
 /**
  * CLI subcommand definitions
  *
- * Registers all named subcommands (run, watch, add, list, switch, clear, eject, config, prompt).
+ * Registers all named subcommands (run, watch, add, list, switch, clear, eject, config, prompt, catalog).
  */
 
 import { clearPersonaSessions, getCurrentPiece } from '../../infra/config/index.js';
@@ -9,6 +9,7 @@ import { success } from '../../shared/ui/index.js';
 import { runAllTasks, addTask, watchTasks, listTasks } from '../../features/tasks/index.js';
 import { switchPiece, switchConfig, ejectBuiltin, resetCategoriesToDefault, deploySkill } from '../../features/config/index.js';
 import { previewPrompts } from '../../features/prompt/index.js';
+import { showCatalog } from '../../features/catalog/index.js';
 import { program, resolvedCwd } from './program.js';
 import { resolveAgentOverrides } from './helpers.js';
 
@@ -115,3 +116,11 @@ program
   .action(async () => {
     await deploySkill();
   });
+
+program
+  .command('catalog')
+  .description('List available facets (personas, policies, knowledge, instructions, output-contracts)')
+  .argument('[type]', 'Facet type to list')
+  .action((type?: string) => {
+    showCatalog(resolvedCwd, type);
+  });
diff --git a/src/features/catalog/catalogFacets.ts b/src/features/catalog/catalogFacets.ts
new file mode 100644
index 0000000..5a37a43
--- /dev/null
+++ b/src/features/catalog/catalogFacets.ts
@@ -0,0 +1,178 @@
+/**
+ * Facet catalog — scan and display available facets across 3 layers.
+ *
+ * Scans builtin, user (~/.takt/), and project (.takt/) directories
+ * for facet files (.md) and displays them with layer provenance.
+ */
+
+import { existsSync, readdirSync, readFileSync } from 'node:fs';
+import { join, basename } from 'node:path';
+import chalk from 'chalk';
+import type { PieceSource } from '../../infra/config/loaders/pieceResolver.js';
+import { getLanguageResourcesDir } from '../../infra/resources/index.js';
+import { getGlobalConfigDir, getProjectConfigDir } from '../../infra/config/paths.js';
+import { getLanguage, getBuiltinPiecesEnabled } from '../../infra/config/global/globalConfig.js';
+import { section, error as logError, info } from '../../shared/ui/index.js';
+
+const FACET_TYPES = [
+  'personas',
+  'policies',
+  'knowledge',
+  'instructions',
+  'output-contracts',
+] as const;
+
+export type FacetType = (typeof FACET_TYPES)[number];
+
+export interface FacetEntry {
+  name: string;
+  description: string;
+  source: PieceSource;
+  overriddenBy?: PieceSource;
+}
+
+/** Validate a string as a FacetType. Returns the type or null. */
+export function parseFacetType(input: string): FacetType | null {
+  if ((FACET_TYPES as readonly string[]).includes(input)) {
+    return input as FacetType;
+  }
+  return null;
+}
+
+/**
+ * Extract description from a markdown file.
+ * Returns the first `# ` heading text, or falls back to the first non-empty line.
+ */
+export function extractDescription(filePath: string): string {
+  const content = readFileSync(filePath, 'utf-8');
+  let firstNonEmpty = '';
+  for (const line of content.split('\n')) {
+    if (line.startsWith('# ')) {
+      return line.slice(2).trim();
+    }
+    if (!firstNonEmpty && line.trim()) {
+      firstNonEmpty = line.trim();
+    }
+  }
+  return firstNonEmpty;
+}
+
+/** Build the 3-layer directory list for a given facet type. */
+function getFacetDirs(
+  facetType: FacetType,
+  cwd: string,
+): { dir: string; source: PieceSource }[] {
+  const dirs: { dir: string; source: PieceSource }[] = [];
+
+  if (getBuiltinPiecesEnabled()) {
+    const lang = getLanguage();
+    dirs.push({ dir: join(getLanguageResourcesDir(lang), facetType), source: 'builtin' });
+  }
+
+  dirs.push({ dir: join(getGlobalConfigDir(), facetType), source: 'user' });
+  dirs.push({ dir: join(getProjectConfigDir(cwd), facetType), source: 'project' });
+
+  return dirs;
+}
+
+/** Scan a single directory for .md facet files. */
+function scanDirectory(dir: string): string[] {
+  if (!existsSync(dir)) return [];
+  return readdirSync(dir).filter((f) => f.endsWith('.md'));
+}
+
+/**
+ * Scan all layers for facets of a given type.
+ *
+ * Scans builtin → user → project in order.
+ * When a facet name appears in a higher-priority layer, the lower-priority
+ * entry gets `overriddenBy` set to the overriding layer.
+ */
+export function scanFacets(facetType: FacetType, cwd: string): FacetEntry[] {
+  const dirs = getFacetDirs(facetType, cwd);
+  const entriesByName = new Map<string, FacetEntry>();
+  const allEntries: FacetEntry[] = [];
+
+  for (const { dir, source } of dirs) {
+    const files = scanDirectory(dir);
+    for (const file of files) {
+      const name = basename(file, '.md');
+      const description = extractDescription(join(dir, file));
+      const entry: FacetEntry = { name, description, source };
+
+      const existing = entriesByName.get(name);
+      if (existing) {
+        existing.overriddenBy = source;
+      }
+
+      entriesByName.set(name, entry);
+      allEntries.push(entry);
+    }
+  }
+
+  return allEntries;
+}
+
+/** Color a source tag for terminal display. */
+function colorSourceTag(source: PieceSource): string {
+  switch (source) {
+    case 'builtin':
+      return chalk.gray(`[${source}]`);
+    case 'user':
+      return chalk.yellow(`[${source}]`);
+    case 'project':
+      return chalk.green(`[${source}]`);
+  }
+}
+
+/** Format and print a list of facet entries for one facet type. */
+export function displayFacets(facetType: FacetType, entries: FacetEntry[]): void {
+  section(`${capitalize(facetType)}:`);
+
+  if (entries.length === 0) {
+    console.log(chalk.gray('  (none)'));
+    return;
+  }
+
+  const maxNameLen = Math.max(...entries.map((e) => e.name.length));
+  const maxDescLen = Math.max(...entries.map((e) => e.description.length));
+
+  for (const entry of entries) {
+    const name = entry.name.padEnd(maxNameLen + 2);
+    const desc = entry.description.padEnd(maxDescLen + 2);
+    const tag = colorSourceTag(entry.source);
+    const override = entry.overriddenBy
+      ? chalk.gray(` (overridden by ${entry.overriddenBy})`)
+      : '';
+    console.log(`  ${name}${chalk.dim(desc)}${tag}${override}`);
+  }
+}
+
+function capitalize(s: string): string {
+  return s.charAt(0).toUpperCase() + s.slice(1);
+}
+
+/**
+ * Main entry point: show facet catalog.
+ *
+ * If facetType is provided, shows only that type.
+ * Otherwise shows all facet types.
+ */
+export function showCatalog(cwd: string, facetType?: string): void {
+  if (facetType !== undefined) {
+    const parsed = parseFacetType(facetType);
+    if (!parsed) {
+      logError(`Unknown facet type: "${facetType}"`);
+      info(`Available types: ${FACET_TYPES.join(', ')}`);
+      return;
+    }
+    const entries = scanFacets(parsed, cwd);
+    displayFacets(parsed, entries);
+    return;
+  }
+
+  for (const type of FACET_TYPES) {
+    const entries = scanFacets(type, cwd);
+    displayFacets(type, entries);
+  }
+}
diff --git a/src/features/catalog/index.ts b/src/features/catalog/index.ts
new file mode 100644
index 0000000..eb094e6
--- /dev/null
+++ b/src/features/catalog/index.ts
@@ -0,0 +1,5 @@
+/**
+ * Catalog feature — list available facets across layers.
+ */
+
+export { showCatalog } from './catalogFacets.js';