TAKTのメタ情報をエージェントに引き渡す。またTAKTの前回セッションの情報をscoreフェーズに追加 resolved #89

src/__tests__/addTask.test.ts

@@ -50,7 +50,11 @@ vi.mock('../features/tasks/execute/selectAndExecute.js', () => ({
 }));
 
 vi.mock('../infra/config/loaders/pieceResolver.js', () => ({
-  getPieceDescription: vi.fn(() => ({ name: 'default', description: '' })),
+  getPieceDescription: vi.fn(() => ({
+    name: 'default',
+    description: '',
+    pieceStructure: '1. implement\n2. review'
+  })),
 }));
 
 vi.mock('../infra/github/issue.js', () => ({
@@ -92,7 +96,7 @@ function setupFullFlowMocks(overrides?: {
   const slug = overrides?.slug ?? 'add-auth';
 
   mockDeterminePiece.mockResolvedValue('default');
-  mockGetPieceDescription.mockReturnValue({ name: 'default', description: '' });
+  mockGetPieceDescription.mockReturnValue({ name: 'default', description: '', pieceStructure: '' });
   mockInteractiveMode.mockResolvedValue({ confirmed: true, task });
   mockSummarizeTaskName.mockResolvedValue(slug);
   mockConfirm.mockResolvedValue(false);
@@ -104,7 +108,7 @@ beforeEach(() => {
   vi.clearAllMocks();
   testDir = fs.mkdtempSync(path.join(tmpdir(), 'takt-test-'));
   mockDeterminePiece.mockResolvedValue('default');
-  mockGetPieceDescription.mockReturnValue({ name: 'default', description: '' });
+  mockGetPieceDescription.mockReturnValue({ name: 'default', description: '', pieceStructure: '' });
   mockConfirm.mockResolvedValue(false);
 });
 
@@ -225,7 +229,7 @@ describe('addTask', () => {
     // Given: determinePiece returns a non-default piece
     setupFullFlowMocks({ slug: 'with-piece' });
     mockDeterminePiece.mockResolvedValue('review');
-    mockGetPieceDescription.mockReturnValue({ name: 'review', description: 'Code review piece' });
+    mockGetPieceDescription.mockReturnValue({ name: 'review', description: 'Code review piece', pieceStructure: '' });
     mockConfirm.mockResolvedValue(false);
 
     // When

src/__tests__/instructionBuilder.test.ts

@@ -46,6 +46,8 @@ function createMinimalContext(overrides: Partial<InstructionContext> = {}): Inst
     cwd: '/project',
     projectCwd: '/project',
     userInputs: [],
+    pieceName: 'test-piece',
+    pieceDescription: 'Test piece description',
     ...overrides,
   };
 }
@@ -299,6 +301,62 @@ describe('instruction-builder', () => {
   });
 
   describe('auto-injected Piece Context section', () => {
+    it('should include piece name when provided', () => {
+      const step = createMinimalStep('Do work');
+      const context = createMinimalContext({
+        pieceName: 'my-piece',
+        language: 'en',
+      });
+
+      const result = buildInstruction(step, context);
+
+      expect(result).toContain('## Piece Context');
+      expect(result).toContain('- Piece: my-piece');
+    });
+
+    it('should include piece description when provided', () => {
+      const step = createMinimalStep('Do work');
+      const context = createMinimalContext({
+        pieceName: 'my-piece',
+        pieceDescription: 'A test piece for validation',
+        language: 'en',
+      });
+
+      const result = buildInstruction(step, context);
+
+      expect(result).toContain('## Piece Context');
+      expect(result).toContain('- Piece: my-piece');
+      expect(result).toContain('- Description: A test piece for validation');
+    });
+
+    it('should not show description when not provided', () => {
+      const step = createMinimalStep('Do work');
+      const context = createMinimalContext({
+        pieceName: 'my-piece',
+        pieceDescription: undefined,
+        language: 'en',
+      });
+
+      const result = buildInstruction(step, context);
+
+      expect(result).toContain('- Piece: my-piece');
+      expect(result).not.toContain('- Description:');
+    });
+
+    it('should render piece context in Japanese', () => {
+      const step = createMinimalStep('Do work');
+      const context = createMinimalContext({
+        pieceName: 'coding',
+        pieceDescription: 'コーディングピース',
+        language: 'ja',
+      });
+
+      const result = buildInstruction(step, context);
+
+      expect(result).toContain('- ピース: coding');
+      expect(result).toContain('- 説明: コーディングピース');
+    });
+
     it('should include iteration, step iteration, and step name', () => {
       const step = createMinimalStep('Do work');
       step.name = 'implement';

src/__tests__/interactive.test.ts

@@ -31,6 +31,8 @@ vi.mock('../infra/config/paths.js', async (importOriginal) => ({
   loadAgentSessions: vi.fn(() => ({})),
   updateAgentSession: vi.fn(),
   getProjectConfigDir: vi.fn(() => '/tmp'),
+  loadSessionState: vi.fn(() => null),
+  clearSessionState: vi.fn(),
 }));
 
 vi.mock('../shared/ui/index.js', () => ({
@@ -279,4 +281,59 @@ describe('interactiveMode', () => {
     expect(result.confirmed).toBe(true);
     expect(result.task).toBe('Fix login page with clarified scope.');
   });
+
+  describe('/play command', () => {
+    it('should return confirmed=true with task on /play command', async () => {
+      // Given
+      setupInputSequence(['/play implement login feature']);
+      setupMockProvider([]);
+
+      // When
+      const result = await interactiveMode('/project');
+
+      // Then
+      expect(result.confirmed).toBe(true);
+      expect(result.task).toBe('implement login feature');
+    });
+
+    it('should show error when /play has no task content', async () => {
+      // Given: /play without task, then /cancel to exit
+      setupInputSequence(['/play', '/cancel']);
+      setupMockProvider([]);
+
+      // When
+      const result = await interactiveMode('/project');
+
+      // Then: should not confirm (fell through to /cancel)
+      expect(result.confirmed).toBe(false);
+    });
+
+    it('should handle /play with leading/trailing spaces', async () => {
+      // Given
+      setupInputSequence(['/play   test task  ']);
+      setupMockProvider([]);
+
+      // When
+      const result = await interactiveMode('/project');
+
+      // Then
+      expect(result.confirmed).toBe(true);
+      expect(result.task).toBe('test task');
+    });
+
+    it('should skip AI summary when using /play', async () => {
+      // Given
+      setupInputSequence(['/play quick task']);
+      setupMockProvider([]);
+
+      // When
+      const result = await interactiveMode('/project');
+
+      // Then: provider should NOT have been called (no summary needed)
+      const mockProvider = mockGetProvider.mock.results[0]?.value as { call: ReturnType<typeof vi.fn> };
+      expect(mockProvider.call).not.toHaveBeenCalled();
+      expect(result.confirmed).toBe(true);
+      expect(result.task).toBe('quick task');
+    });
+  });
 });

src/__tests__/pieceResolver.test.ts

@@ -0,0 +1,155 @@
+/**
+ * Tests for getPieceDescription and buildWorkflowString
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdtempSync, writeFileSync, mkdirSync, rmSync } from 'node:fs';
+import { join } from 'node:path';
+import { tmpdir } from 'node:os';
+import { getPieceDescription } from '../infra/config/loaders/pieceResolver.js';
+
+describe('getPieceDescription', () => {
+  let tempDir: string;
+
+  beforeEach(() => {
+    tempDir = mkdtempSync(join(tmpdir(), 'takt-test-piece-resolver-'));
+  });
+
+  afterEach(() => {
+    rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('should return workflow structure with sequential movements', () => {
+    const pieceYaml = `name: test-piece
+description: Test piece for workflow
+initial_movement: plan
+max_iterations: 3
+
+movements:
+  - name: plan
+    description: タスク計画
+    agent: planner
+    instruction: "Plan the task"
+  - name: implement
+    description: 実装
+    agent: coder
+    instruction: "Implement"
+  - name: review
+    agent: reviewer
+    instruction: "Review"
+`;
+
+    const piecePath = join(tempDir, 'test.yaml');
+    writeFileSync(piecePath, pieceYaml);
+
+    const result = getPieceDescription(piecePath, tempDir);
+
+    expect(result.name).toBe('test-piece');
+    expect(result.description).toBe('Test piece for workflow');
+    expect(result.pieceStructure).toBe(
+      '1. plan (タスク計画)\n2. implement (実装)\n3. review'
+    );
+  });
+
+  it('should return workflow structure with parallel movements', () => {
+    const pieceYaml = `name: coding
+description: Full coding workflow
+initial_movement: plan
+max_iterations: 10
+
+movements:
+  - name: plan
+    description: タスク計画
+    agent: planner
+    instruction: "Plan"
+  - name: reviewers
+    description: 並列レビュー
+    parallel:
+      - name: ai_review
+        agent: ai-reviewer
+        instruction: "AI review"
+      - name: arch_review
+        agent: arch-reviewer
+        instruction: "Architecture review"
+  - name: fix
+    description: 修正
+    agent: coder
+    instruction: "Fix"
+`;
+
+    const piecePath = join(tempDir, 'coding.yaml');
+    writeFileSync(piecePath, pieceYaml);
+
+    const result = getPieceDescription(piecePath, tempDir);
+
+    expect(result.name).toBe('coding');
+    expect(result.description).toBe('Full coding workflow');
+    expect(result.pieceStructure).toBe(
+      '1. plan (タスク計画)\n' +
+      '2. reviewers (並列レビュー)\n' +
+      '   - ai_review\n' +
+      '   - arch_review\n' +
+      '3. fix (修正)'
+    );
+  });
+
+  it('should handle movements without descriptions', () => {
+    const pieceYaml = `name: minimal
+initial_movement: step1
+max_iterations: 1
+
+movements:
+  - name: step1
+    agent: coder
+    instruction: "Do step1"
+  - name: step2
+    agent: coder
+    instruction: "Do step2"
+`;
+
+    const piecePath = join(tempDir, 'minimal.yaml');
+    writeFileSync(piecePath, pieceYaml);
+
+    const result = getPieceDescription(piecePath, tempDir);
+
+    expect(result.name).toBe('minimal');
+    expect(result.description).toBe('');
+    expect(result.pieceStructure).toBe('1. step1\n2. step2');
+  });
+
+  it('should return empty strings when piece is not found', () => {
+    const result = getPieceDescription('nonexistent', tempDir);
+
+    expect(result.name).toBe('nonexistent');
+    expect(result.description).toBe('');
+    expect(result.pieceStructure).toBe('');
+  });
+
+  it('should handle parallel movements without descriptions', () => {
+    const pieceYaml = `name: test-parallel
+initial_movement: parent
+max_iterations: 1
+
+movements:
+  - name: parent
+    parallel:
+      - name: child1
+        agent: agent1
+        instruction: "Do child1"
+      - name: child2
+        agent: agent2
+        instruction: "Do child2"
+`;
+
+    const piecePath = join(tempDir, 'test-parallel.yaml');
+    writeFileSync(piecePath, pieceYaml);
+
+    const result = getPieceDescription(piecePath, tempDir);
+
+    expect(result.pieceStructure).toBe(
+      '1. parent\n' +
+      '   - child1\n' +
+      '   - child2'
+    );
+  });
+});

src/__tests__/prompts.test.ts

@@ -57,14 +57,15 @@ describe('variable substitution', () => {
     expect(result).toContain('| 1 | Success |');
   });
 
-  it('replaces piece info variables in interactive prompt', () => {
+  it('interactive prompt does not contain piece info', () => {
     const result = loadTemplate('score_interactive_system_prompt', 'en', {
       pieceInfo: true,
       pieceName: 'my-piece',
       pieceDescription: 'Test description',
     });
-    expect(result).toContain('"my-piece"');
+    // ピース情報はインタラクティブプロンプトには含まれない（要約プロンプトにのみ含まれる）
-    expect(result).toContain('Test description');
+    expect(result).not.toContain('"my-piece"');
+    expect(result).not.toContain('Test description');
   });
 });
 

src/__tests__/sessionState.test.ts

@@ -0,0 +1,186 @@
+/**
+ * Session state management tests
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdirSync, rmSync, existsSync } from 'node:fs';
+import { join } from 'node:path';
+import {
+  loadSessionState,
+  saveSessionState,
+  clearSessionState,
+  getSessionStatePath,
+  type SessionState,
+} from '../infra/config/project/sessionState.js';
+
+describe('sessionState', () => {
+  const testDir = join(__dirname, '__temp_session_state_test__');
+
+  beforeEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+    mkdirSync(testDir, { recursive: true });
+  });
+
+  afterEach(() => {
+    if (existsSync(testDir)) {
+      rmSync(testDir, { recursive: true, force: true });
+    }
+  });
+
+  describe('getSessionStatePath', () => {
+    it('should return correct path', () => {
+      const path = getSessionStatePath(testDir);
+      expect(path).toContain('.takt');
+      expect(path).toContain('session-state.json');
+    });
+  });
+
+  describe('loadSessionState', () => {
+    it('should return null when file does not exist', () => {
+      const state = loadSessionState(testDir);
+      expect(state).toBeNull();
+    });
+
+    it('should load saved state', () => {
+      const savedState: SessionState = {
+        status: 'success',
+        taskResult: 'Task completed successfully',
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+        taskContent: 'Implement feature X',
+        lastMovement: 'implement',
+      };
+
+      saveSessionState(testDir, savedState);
+      const loadedState = loadSessionState(testDir);
+
+      expect(loadedState).toEqual(savedState);
+    });
+
+    it('should return null when JSON parsing fails', () => {
+      const path = getSessionStatePath(testDir);
+      const configDir = join(testDir, '.takt');
+      mkdirSync(configDir, { recursive: true });
+
+      // Write invalid JSON
+      const fs = require('node:fs');
+      fs.writeFileSync(path, 'invalid json', 'utf-8');
+
+      const state = loadSessionState(testDir);
+      expect(state).toBeNull();
+    });
+  });
+
+  describe('saveSessionState', () => {
+    it('should save state correctly', () => {
+      const state: SessionState = {
+        status: 'success',
+        taskResult: 'Task completed',
+        timestamp: new Date().toISOString(),
+        pieceName: 'minimal',
+        taskContent: 'Test task',
+        lastMovement: 'test-movement',
+      };
+
+      saveSessionState(testDir, state);
+
+      const path = getSessionStatePath(testDir);
+      expect(existsSync(path)).toBe(true);
+
+      const loaded = loadSessionState(testDir);
+      expect(loaded).toEqual(state);
+    });
+
+    it('should save error state', () => {
+      const state: SessionState = {
+        status: 'error',
+        errorMessage: 'Something went wrong',
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+        taskContent: 'Failed task',
+      };
+
+      saveSessionState(testDir, state);
+      const loaded = loadSessionState(testDir);
+
+      expect(loaded).toEqual(state);
+    });
+
+    it('should save user_stopped state', () => {
+      const state: SessionState = {
+        status: 'user_stopped',
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+        taskContent: 'Interrupted task',
+      };
+
+      saveSessionState(testDir, state);
+      const loaded = loadSessionState(testDir);
+
+      expect(loaded).toEqual(state);
+    });
+  });
+
+  describe('clearSessionState', () => {
+    it('should delete state file', () => {
+      const state: SessionState = {
+        status: 'success',
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+      };
+
+      saveSessionState(testDir, state);
+      const path = getSessionStatePath(testDir);
+      expect(existsSync(path)).toBe(true);
+
+      clearSessionState(testDir);
+      expect(existsSync(path)).toBe(false);
+    });
+
+    it('should not throw when file does not exist', () => {
+      expect(() => clearSessionState(testDir)).not.toThrow();
+    });
+  });
+
+  describe('integration', () => {
+    it('should support one-time notification pattern', () => {
+      // Save state
+      const state: SessionState = {
+        status: 'success',
+        taskResult: 'Done',
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+      };
+      saveSessionState(testDir, state);
+
+      // Load once
+      const loaded1 = loadSessionState(testDir);
+      expect(loaded1).toEqual(state);
+
+      // Clear immediately
+      clearSessionState(testDir);
+
+      // Load again - should be null
+      const loaded2 = loadSessionState(testDir);
+      expect(loaded2).toBeNull();
+    });
+
+    it('should handle truncated strings', () => {
+      const longString = 'a'.repeat(2000);
+      const state: SessionState = {
+        status: 'success',
+        taskResult: longString,
+        timestamp: new Date().toISOString(),
+        pieceName: 'coding',
+        taskContent: longString,
+      };
+
+      saveSessionState(testDir, state);
+      const loaded = loadSessionState(testDir);
+
+      expect(loaded).toEqual(state);
+    });
+  });
+});

src/agents/runner.ts

@@ -196,7 +196,20 @@ export class AgentRunner {
     if (options.agentPath) {
       const agentDefinition = AgentRunner.loadAgentPromptFromPath(options.agentPath);
       const language = options.language ?? 'en';
-      const systemPrompt = loadTemplate('perform_agent_system_prompt', language, { agentDefinition });
+      const templateVars: Record<string, string> = { agentDefinition };
+
+      // Add piece meta information if available
+      if (options.pieceMeta) {
+        templateVars.pieceName = options.pieceMeta.pieceName;
+        templateVars.pieceDescription = options.pieceMeta.pieceDescription ?? '';
+        templateVars.currentMovement = options.pieceMeta.currentMovement;
+        templateVars.movementsList = options.pieceMeta.movementsList
+          .map((m, i) => `${i + 1}. ${m.name}${m.description ? ` - ${m.description}` : ''}`)
+          .join('\n');
+        templateVars.currentPosition = options.pieceMeta.currentPosition;
+      }
+
+      const systemPrompt = loadTemplate('perform_agent_system_prompt', language, templateVars);
       const providerType = AgentRunner.resolveProvider(options.cwd, options);
       const provider = getProvider(providerType);
       return provider.call(agentName, task, AgentRunner.buildProviderCallOptions(options, systemPrompt));

src/agents/types.ts

@@ -28,4 +28,12 @@ export interface RunAgentOptions {
   bypassPermissions?: boolean;
   /** Language for template resolution */
   language?: Language;
+  /** Piece meta information for system prompt template */
+  pieceMeta?: {
+    pieceName: string;
+    pieceDescription?: string;
+    currentMovement: string;
+    movementsList: ReadonlyArray<{ name: string; description?: string }>;
+    currentPosition: string;
+  };
 }

src/core/piece/engine/MovementExecutor.ts

@@ -33,6 +33,8 @@ export interface MovementExecutorDeps {
   readonly getLanguage: () => Language | undefined;
   readonly getInteractive: () => boolean;
   readonly getPieceMovements: () => ReadonlyArray<{ name: string; description?: string }>;
+  readonly getPieceName: () => string;
+  readonly getPieceDescription: () => string | undefined;
   readonly detectRuleIndex: (content: string, movementName: string) => number;
   readonly callAiJudge: (
     agentOutput: string,
@@ -71,6 +73,8 @@ export class MovementExecutor {
       interactive: this.deps.getInteractive(),
       pieceMovements: pieceMovements,
       currentMovementIndex: pieceMovements.findIndex(s => s.name === step.name),
+      pieceName: this.deps.getPieceName(),
+      pieceDescription: this.deps.getPieceDescription(),
     }).build();
   }
 

src/core/piece/engine/OptionsBuilder.ts

@@ -19,10 +19,17 @@ export class OptionsBuilder {
     private readonly getSessionId: (agent: string) => string | undefined,
     private readonly getReportDir: () => string,
     private readonly getLanguage: () => Language | undefined,
+    private readonly getPieceMovements: () => ReadonlyArray<{ name: string; description?: string }>,
+    private readonly getPieceName: () => string,
+    private readonly getPieceDescription: () => string | undefined,
   ) {}
 
   /** Build common RunAgentOptions shared by all phases */
   buildBaseOptions(step: PieceMovement): RunAgentOptions {
+    const movements = this.getPieceMovements();
+    const currentIndex = movements.findIndex((m) => m.name === step.name);
+    const currentPosition = currentIndex >= 0 ? `${currentIndex + 1}/${movements.length}` : '?/?';
+
     return {
       cwd: this.getCwd(),
       agentPath: step.agentPath,
@@ -34,6 +41,13 @@ export class OptionsBuilder {
       onPermissionRequest: this.engineOptions.onPermissionRequest,
       onAskUserQuestion: this.engineOptions.onAskUserQuestion,
       bypassPermissions: this.engineOptions.bypassPermissions,
+      pieceMeta: {
+        pieceName: this.getPieceName(),
+        pieceDescription: this.getPieceDescription(),
+        currentMovement: step.name,
+        movementsList: movements,
+        currentPosition,
+      },
     };
   }
 

src/core/piece/engine/PieceEngine.ts

@@ -91,6 +91,9 @@ export class PieceEngine extends EventEmitter {
       (agent) => this.state.agentSessions.get(agent),
       () => this.reportDir,
       () => this.options.language,
+      () => this.config.movements.map(s => ({ name: s.name, description: s.description })),
+      () => this.getPieceName(),
+      () => this.getPieceDescription(),
     );
 
     this.movementExecutor = new MovementExecutor({
@@ -101,6 +104,8 @@ export class PieceEngine extends EventEmitter {
       getLanguage: () => this.options.language,
       getInteractive: () => this.options.interactive === true,
       getPieceMovements: () => this.config.movements.map(s => ({ name: s.name, description: s.description })),
+      getPieceName: () => this.getPieceName(),
+      getPieceDescription: () => this.getPieceDescription(),
       detectRuleIndex: this.detectRuleIndex,
       callAiJudge: this.callAiJudge,
       onPhaseStart: (step, phase, phaseName, instruction) => {
@@ -205,6 +210,16 @@ export class PieceEngine extends EventEmitter {
     return this.projectCwd;
   }
 
+  /** Get piece name */
+  private getPieceName(): string {
+    return this.config.name;
+  }
+
+  /** Get piece description */
+  private getPieceDescription(): string | undefined {
+    return this.config.description;
+  }
+
   /** Request graceful abort: interrupt running queries and stop after current movement */
   abort(): void {
     if (this.abortRequested) return;

src/core/piece/instruction/InstructionBuilder.ts

@@ -89,9 +89,17 @@ export class InstructionBuilder {
       this.context,
     );
 
+    // Piece name and description
+    const pieceName = this.context.pieceName ?? '';
+    const pieceDescription = this.context.pieceDescription ?? '';
+    const hasPieceDescription = !!pieceDescription;
+
     return loadTemplate('perform_phase1_message', language, {
       workingDirectory: this.context.cwd,
       editRule,
+      pieceName,
+      pieceDescription,
+      hasPieceDescription,
       pieceStructure,
       iteration: `${this.context.iteration}/${this.context.maxIterations}`,
       movementIteration: String(this.context.movementIteration),

src/core/piece/instruction/instruction-context.ts

@@ -36,6 +36,10 @@ export interface InstructionContext {
   pieceMovements?: ReadonlyArray<{ name: string; description?: string }>;
   /** Index of the current movement in pieceMovements (0-based) */
   currentMovementIndex?: number;
+  /** Piece name */
+  pieceName?: string;
+  /** Piece description (optional) */
+  pieceDescription?: string;
 }
 
 /**

src/features/interactive/interactive.ts

@@ -13,7 +13,14 @@
 import * as readline from 'node:readline';
 import chalk from 'chalk';
 import type { Language } from '../../core/models/index.js';
-import { loadGlobalConfig, loadAgentSessions, updateAgentSession } from '../../infra/config/index.js';
+import {
+  loadGlobalConfig,
+  loadAgentSessions,
+  updateAgentSession,
+  loadSessionState,
+  clearSessionState,
+  type SessionState,
+} from '../../infra/config/index.js';
 import { isQuietMode } from '../../shared/context.js';
 import { getProvider, type ProviderType } from '../../infra/providers/index.js';
 import { selectOption } from '../../shared/prompt/index.js';
@@ -33,6 +40,44 @@ interface InteractiveUIText {
   proposed: string;
   confirm: string;
   cancelled: string;
+  playNoTask: string;
+}
+
+/**
+ * Format session state for display
+ */
+function formatSessionStatus(state: SessionState, lang: 'en' | 'ja'): string {
+  const lines: string[] = [];
+
+  // Status line
+  if (state.status === 'success') {
+    lines.push(getLabel('interactive.previousTask.success', lang));
+  } else if (state.status === 'error') {
+    lines.push(
+      getLabel('interactive.previousTask.error', lang, {
+        error: state.errorMessage!,
+      })
+    );
+  } else if (state.status === 'user_stopped') {
+    lines.push(getLabel('interactive.previousTask.userStopped', lang));
+  }
+
+  // Piece name
+  lines.push(
+    getLabel('interactive.previousTask.piece', lang, {
+      pieceName: state.pieceName,
+    })
+  );
+
+  // Timestamp
+  const timestamp = new Date(state.timestamp).toLocaleString(lang === 'ja' ? 'ja-JP' : 'en-US');
+  lines.push(
+    getLabel('interactive.previousTask.timestamp', lang, {
+      timestamp,
+    })
+  );
+
+  return lines.join('\n');
 }
 
 function resolveLanguage(lang?: Language): 'en' | 'ja' {
@@ -40,13 +85,7 @@ function resolveLanguage(lang?: Language): 'en' | 'ja' {
 }
 
 function getInteractivePrompts(lang: 'en' | 'ja', pieceContext?: PieceContext) {
-  const hasPiece = !!pieceContext;
+  const systemPrompt = loadTemplate('score_interactive_system_prompt', lang, {});
-
-  const systemPrompt = loadTemplate('score_interactive_system_prompt', lang, {
-    pieceInfo: hasPiece,
-    pieceName: pieceContext?.name ?? '',
-    pieceDescription: pieceContext?.description ?? '',
-  });
 
   return {
     systemPrompt,
@@ -194,6 +233,8 @@ export interface PieceContext {
   name: string;
   /** Piece description */
   description: string;
+  /** Piece structure (numbered list of movements) */
+  pieceStructure: string;
 }
 
 /**
@@ -225,6 +266,15 @@ export async function interactiveMode(
   const savedSessions = loadAgentSessions(cwd, providerType);
   let sessionId: string | undefined = savedSessions[agentName];
 
+  // Load and display previous task state
+  const sessionState = loadSessionState(cwd);
+  if (sessionState) {
+    const statusLabel = formatSessionStatus(sessionState, lang);
+    info(statusLabel);
+    blankLine();
+    clearSessionState(cwd);
+  }
+
   info(prompts.ui.intro);
   if (sessionId) {
     info(prompts.ui.resume);
@@ -315,6 +365,16 @@ export async function interactiveMode(
     }
 
     // Handle slash commands
+    if (trimmed.startsWith('/play')) {
+      const task = trimmed.slice(5).trim();
+      if (!task) {
+        info(prompts.ui.playNoTask);
+        continue;
+      }
+      log.info('Play command', { task });
+      return { confirmed: true, task };
+    }
+
     if (trimmed.startsWith('/go')) {
       const userNote = trimmed.slice(3).trim();
       let summaryPrompt = buildSummaryPrompt(

src/features/tasks/execute/pieceExecution.ts

@@ -16,6 +16,8 @@ import {
   loadWorktreeSessions,
   updateWorktreeSession,
   loadGlobalConfig,
+  saveSessionState,
+  type SessionState,
 } from '../../../infra/config/index.js';
 import { isQuietMode } from '../../../shared/context.js';
 import {
@@ -51,6 +53,16 @@ import { getLabel } from '../../../shared/i18n/index.js';
 
 const log = createLogger('piece');
 
+/**
+ * Truncate string to maximum length
+ */
+function truncate(str: string, maxLength: number): string {
+  if (str.length <= maxLength) {
+    return str;
+  }
+  return str.slice(0, maxLength) + '...';
+}
+
 /**
  * Format elapsed time in human-readable format
  */
@@ -219,6 +231,8 @@ export async function executePiece(
   });
 
   let abortReason: string | undefined;
+  let lastMovementContent: string | undefined;
+  let lastMovementName: string | undefined;
 
   engine.on('phase:start', (step, phase, phaseName, instruction) => {
     log.debug('Phase starting', { step: step.name, phase, phaseName });
@@ -283,6 +297,11 @@ export async function executePiece(
       sessionId: response.sessionId,
       error: response.error,
     });
+
+    // Capture last movement output for session state
+    lastMovementContent = response.content;
+    lastMovementName = step.name;
+
     if (displayRef.current) {
       displayRef.current.flush();
       displayRef.current = null;
@@ -348,6 +367,21 @@ export async function executePiece(
     appendNdjsonLine(ndjsonLogPath, record);
     updateLatestPointer(sessionLog, pieceSessionId, projectCwd);
 
+    // Save session state for next interactive mode
+    try {
+      const sessionState: SessionState = {
+        status: 'success',
+        taskResult: truncate(lastMovementContent ?? '', 1000),
+        timestamp: new Date().toISOString(),
+        pieceName: pieceConfig.name,
+        taskContent: truncate(task, 200),
+        lastMovement: lastMovementName,
+      };
+      saveSessionState(projectCwd, sessionState);
+    } catch (error) {
+      log.error('Failed to save session state', { error });
+    }
+
     const elapsed = sessionLog.endTime
       ? formatElapsedTime(sessionLog.startTime, sessionLog.endTime)
       : '';
@@ -378,6 +412,21 @@ export async function executePiece(
     appendNdjsonLine(ndjsonLogPath, record);
     updateLatestPointer(sessionLog, pieceSessionId, projectCwd);
 
+    // Save session state for next interactive mode
+    try {
+      const sessionState: SessionState = {
+        status: reason === 'user_interrupted' ? 'user_stopped' : 'error',
+        errorMessage: reason,
+        timestamp: new Date().toISOString(),
+        pieceName: pieceConfig.name,
+        taskContent: truncate(task, 200),
+        lastMovement: lastMovementName,
+      };
+      saveSessionState(projectCwd, sessionState);
+    } catch (error) {
+      log.error('Failed to save session state', { error });
+    }
+
     const elapsed = sessionLog.endTime
       ? formatElapsedTime(sessionLog.startTime, sessionLog.endTime)
       : '';

src/infra/config/loaders/pieceResolver.ts

@@ -8,7 +8,7 @@
 import { existsSync, readdirSync, statSync } from 'node:fs';
 import { join, resolve, isAbsolute } from 'node:path';
 import { homedir } from 'node:os';
-import type { PieceConfig } from '../../../core/models/index.js';
+import type { PieceConfig, PieceMovement } from '../../../core/models/index.js';
 import { getGlobalPiecesDir, getBuiltinPiecesDir, getProjectConfigDir } from '../paths.js';
 import { getLanguage, getDisabledBuiltins, getBuiltinPiecesEnabled } from '../global/globalConfig.js';
 import { createLogger, getErrorMessage } from '../../../shared/utils/index.js';
@@ -145,21 +145,52 @@ export function loadPieceByIdentifier(
   return loadPiece(identifier, projectCwd);
 }
 
+/**
+ * Build workflow structure string from piece movements.
+ * Formats as numbered list with indented parallel sub-movements.
+ *
+ * @param movements - Piece movements list
+ * @returns Workflow structure string (newline-separated list)
+ */
+function buildWorkflowString(movements: PieceMovement[]): string {
+  if (!movements || movements.length === 0) return '';
+
+  const lines: string[] = [];
+  let index = 1;
+
+  for (const movement of movements) {
+    const desc = movement.description ? ` (${movement.description})` : '';
+    lines.push(`${index}. ${movement.name}${desc}`);
+
+    if (movement.parallel && movement.parallel.length > 0) {
+      for (const sub of movement.parallel) {
+        const subDesc = sub.description ? ` (${sub.description})` : '';
+        lines.push(`   - ${sub.name}${subDesc}`);
+      }
+    }
+
+    index++;
+  }
+
+  return lines.join('\n');
+}
+
 /**
  * Get piece description by identifier.
- * Returns the piece name and description (if available).
+ * Returns the piece name, description, and workflow structure.
  */
 export function getPieceDescription(
   identifier: string,
   projectCwd: string,
-): { name: string; description: string } {
+): { name: string; description: string; pieceStructure: string } {
   const piece = loadPieceByIdentifier(identifier, projectCwd);
   if (!piece) {
-    return { name: identifier, description: '' };
+    return { name: identifier, description: '', pieceStructure: '' };
   }
   return {
     name: piece.name,
     description: piece.description ?? '',
+    pieceStructure: buildWorkflowString(piece.movements),
   };
 }
 

src/infra/config/project/index.ts

@@ -34,3 +34,11 @@ export {
   getClaudeProjectSessionsDir,
   clearClaudeProjectSessions,
 } from './sessionStore.js';
+
+export {
+  type SessionState,
+  getSessionStatePath,
+  loadSessionState,
+  saveSessionState,
+  clearSessionState,
+} from './sessionState.js';

src/infra/config/project/sessionState.ts

@@ -0,0 +1,73 @@
+/**
+ * Session state management for TAKT
+ *
+ * Manages the last task execution state for interactive mode notification.
+ */
+
+import { existsSync, readFileSync, unlinkSync } from 'node:fs';
+import { join } from 'node:path';
+import { getProjectConfigDir, ensureDir } from '../paths.js';
+import { writeFileAtomic } from './sessionStore.js';
+
+/** Last task execution state */
+export interface SessionState {
+  /** Task status */
+  status: 'success' | 'error' | 'user_stopped';
+  /** Task result summary (max 1000 chars) */
+  taskResult?: string;
+  /** Error message (if applicable) */
+  errorMessage?: string;
+  /** Execution timestamp (ISO8601) */
+  timestamp: string;
+  /** Piece name used */
+  pieceName: string;
+  /** Task content (max 200 chars) */
+  taskContent?: string;
+  /** Last movement name */
+  lastMovement?: string;
+}
+
+/**
+ * Get path for storing session state
+ */
+export function getSessionStatePath(projectDir: string): string {
+  return join(getProjectConfigDir(projectDir), 'session-state.json');
+}
+
+/**
+ * Load session state from file
+ * Returns null if file doesn't exist or parsing fails
+ */
+export function loadSessionState(projectDir: string): SessionState | null {
+  const path = getSessionStatePath(projectDir);
+  if (!existsSync(path)) {
+    return null;
+  }
+
+  try {
+    const content = readFileSync(path, 'utf-8');
+    return JSON.parse(content) as SessionState;
+  } catch {
+    return null;
+  }
+}
+
+/**
+ * Save session state to file (atomic write)
+ */
+export function saveSessionState(projectDir: string, state: SessionState): void {
+  const path = getSessionStatePath(projectDir);
+  ensureDir(getProjectConfigDir(projectDir));
+  writeFileAtomic(path, JSON.stringify(state, null, 2));
+}
+
+/**
+ * Clear session state file
+ * Does nothing if file doesn't exist
+ */
+export function clearSessionState(projectDir: string): void {
+  const path = getSessionStatePath(projectDir);
+  if (existsSync(path)) {
+    unlinkSync(path);
+  }
+}

src/shared/i18n/labels_en.yaml

@@ -10,7 +10,7 @@ interactive:
   conversationLabel: "Conversation:"
   noTranscript: "(No local transcript. Summarize the current session context.)"
   ui:
-    intro: "Interactive mode - describe your task. Commands: /go (execute), /cancel (exit)"
+    intro: "Interactive mode - describe your task. Commands: /go (execute), /play (run now), /cancel (exit)"
     resume: "Resuming previous session"
     noConversation: "No conversation yet. Please describe your task first."
     summarizeFailed: "Failed to summarize conversation. Please try again."
@@ -18,6 +18,13 @@ interactive:
     proposed: "Proposed task instruction:"
     confirm: "Use this task instruction?"
     cancelled: "Cancelled"
+    playNoTask: "Please specify task content: /play <task>"
+  previousTask:
+    success: "✅ Previous task completed successfully"
+    error: "❌ Previous task failed: {error}"
+    userStopped: "⚠️ Previous task was interrupted by user"
+    piece: "Piece: {pieceName}"
+    timestamp: "Executed: {timestamp}"
 
 # ===== Piece Execution UI =====
 piece:

src/shared/i18n/labels_ja.yaml

@@ -10,7 +10,7 @@ interactive:
   conversationLabel: "会話:"
   noTranscript: "（ローカル履歴なし。現在のセッション文脈を要約してください。）"
   ui:
-    intro: "対話モード - タスク内容を入力してください。コマンド: /go（実行）, /cancel（終了）"
+    intro: "対話モード - タスク内容を入力してください。コマンド: /go（実行）, /play（即実行）, /cancel（終了）"
     resume: "前回のセッションを再開します"
     noConversation: "まだ会話がありません。まずタスク内容を入力してください。"
     summarizeFailed: "会話の要約に失敗しました。再度お試しください。"
@@ -18,6 +18,13 @@ interactive:
     proposed: "提案されたタスク指示:"
     confirm: "このタスク指示で進めますか？"
     cancelled: "キャンセルしました"
+    playNoTask: "タスク内容を指定してください: /play <タスク内容>"
+  previousTask:
+    success: "✅ 前回のタスクは正常に完了しました"
+    error: "❌ 前回のタスクはエラーで終了しました: {error}"
+    userStopped: "⚠️ 前回のタスクはユーザーによって中断されました"
+    piece: "使用ピース: {pieceName}"
+    timestamp: "実行時刻: {timestamp}"
 
 # ===== Piece Execution UI =====
 piece:

src/shared/prompts/en/perform_agent_system_prompt.md

@@ -1,7 +1,25 @@
 <!--
   template: perform_agent_system_prompt
   role: system prompt for user-defined agents
-  vars: agentDefinition
+  vars: agentDefinition, pieceName, pieceDescription, currentMovement, movementsList, currentPosition
   caller: AgentRunner
 -->
+You are part of TAKT (AI Agent Orchestration Tool).
+
+## TAKT Terminology
+- **Piece**: A processing flow combining multiple movements (e.g., implement → review → fix)
+- **Movement**: An individual agent execution unit (the part you are currently handling)
+- **Your Role**: Execute the work assigned to the current movement within the entire piece
+
+## Current Context
+- Piece: {{pieceName}}
+- Current Movement: {{currentMovement}}
+- Processing Flow:
+{{movementsList}}
+- Current Position: {{currentPosition}}
+
+When executing Phase 1, you receive information about the piece name, movement name, and the entire processing flow. Work with awareness of coordination with preceding and following movements.
+
+---
+
 {{agentDefinition}}

src/shared/prompts/en/perform_phase1_message.md

@@ -1,9 +1,10 @@
 <!--
   template: perform_phase1_message
   phase: 1 (main execution)
-  vars: workingDirectory, editRule, pieceStructure, iteration, movementIteration,
+  vars: workingDirectory, editRule, pieceName, pieceDescription, hasPieceDescription,
-        movement, hasReport, reportInfo, phaseNote, hasTaskSection, userRequest,
+        pieceStructure, iteration, movementIteration, movement, hasReport, reportInfo,
-        hasPreviousResponse, previousResponse, hasUserInputs, userInputs, instructions
+        phaseNote, hasTaskSection, userRequest, hasPreviousResponse, previousResponse,
+        hasUserInputs, userInputs, instructions
   builder: InstructionBuilder
 -->
 ## Execution Context
@@ -17,7 +18,10 @@
 Note: This section is metadata. Follow the language used in the rest of the prompt.
 
 ## Piece Context
-{{#if pieceStructure}}{{pieceStructure}}
+{{#if pieceName}}- Piece: {{pieceName}}
+{{/if}}{{#if hasPieceDescription}}- Description: {{pieceDescription}}
+
+{{/if}}{{#if pieceStructure}}{{pieceStructure}}
 
 {{/if}}- Iteration: {{iteration}}(piece-wide)
 - Movement Iteration: {{movementIteration}}(times this movement has run)

src/shared/prompts/en/score_interactive_system_prompt.md

@@ -1,7 +1,7 @@
 <!--
   template: score_interactive_system_prompt
   role: system prompt for interactive planning mode
-  vars: pieceInfo, pieceName, pieceDescription
+  vars: (none)
   caller: features/interactive
 -->
 You are a task planning assistant. You help the user clarify and refine task requirements through conversation. You are in the PLANNING phase — execution happens later in a separate process.
@@ -43,11 +43,8 @@ Do NOT investigate when the user is describing a task for the piece:
 - Do NOT use Read/Glob/Grep/Bash proactively. Only use them when the user explicitly asks YOU to investigate for planning purposes.
 - Do NOT mention or reference any slash commands. You have no knowledge of them.
 - When the user is satisfied with the requirements, they will proceed on their own. Do NOT instruct them on what to do next.
-{{#if pieceInfo}}
 
-## Destination of Your Task Instruction
+## Task Instruction Presentation Rules
-This task instruction will be passed to the "{{pieceName}}" piece.
+- Do NOT present the task instruction during conversation
-Piece description: {{pieceDescription}}
+- ONLY present the current understanding in task instruction format when the user explicitly asks (e.g., "Show me the task instruction", "What does the instruction look like now?")
-
+- The final task instruction is confirmed with user (this is handled automatically by the system)
-Create the instruction in the format expected by this piece.
-{{/if}}

src/shared/prompts/ja/perform_agent_system_prompt.md

@@ -1,7 +1,25 @@
 <!--
   template: perform_agent_system_prompt
   role: system prompt for user-defined agents
-  vars: agentDefinition
+  vars: agentDefinition, pieceName, pieceDescription, currentMovement, movementsList, currentPosition
   caller: AgentRunner
 -->
+あなたはTAKT（AIエージェントオーケストレーションツール）の一部として動作しています。
+
+## TAKTの仕組み
+- **ピース**: 複数のムーブメントを組み合わせた処理フロー（実装→レビュー→修正など）
+- **ムーブメント**: 個別のエージェント実行単位（あなたが今担当している部分）
+- **あなたの役割**: ピース全体の中で、現在のムーブメントに割り当てられた作業を実行する
+
+## 現在のコンテキスト
+- ピース: {{pieceName}}
+- 現在のムーブメント: {{currentMovement}}
+- 処理フロー:
+{{movementsList}}
+- 現在の位置: {{currentPosition}}
+
+Phase 1実行時、あなたはピース名・ムーブメント名・処理フロー全体の情報を受け取ります。前後のムーブメントとの連携を意識して作業してください。
+
+---
+
 {{agentDefinition}}

src/shared/prompts/ja/perform_phase1_message.md

@@ -1,9 +1,10 @@
 <!--
   template: perform_phase1_message
   phase: 1 (main execution)
-  vars: workingDirectory, editRule, pieceStructure, iteration, movementIteration,
+  vars: workingDirectory, editRule, pieceName, pieceDescription, hasPieceDescription,
-        movement, hasReport, reportInfo, phaseNote, hasTaskSection, userRequest,
+        pieceStructure, iteration, movementIteration, movement, hasReport, reportInfo,
-        hasPreviousResponse, previousResponse, hasUserInputs, userInputs, instructions
+        phaseNote, hasTaskSection, userRequest, hasPreviousResponse, previousResponse,
+        hasUserInputs, userInputs, instructions
   builder: InstructionBuilder
 -->
 ## 実行コンテキスト
@@ -16,7 +17,10 @@
 {{/if}}
 
 ## Piece Context
-{{#if pieceStructure}}{{pieceStructure}}
+{{#if pieceName}}- ピース: {{pieceName}}
+{{/if}}{{#if hasPieceDescription}}- 説明: {{pieceDescription}}
+
+{{/if}}{{#if pieceStructure}}{{pieceStructure}}
 
 {{/if}}- Iteration: {{iteration}}（ピース全体）
 - Movement Iteration: {{movementIteration}}（このムーブメントの実行回数）

src/shared/prompts/ja/score_interactive_system_prompt.md

@@ -1,7 +1,7 @@
 <!--
   template: score_interactive_system_prompt
   role: system prompt for interactive planning mode
-  vars: pieceInfo, pieceName, pieceDescription
+  vars: (none)
   caller: features/interactive
 -->
 あなたはTAKT（AIエージェントピースオーケストレーションツール）の対話モードを担当しています。
@@ -49,11 +49,8 @@
 - Read/Glob/Grep/Bash を勝手に使わない。ユーザーが明示的に「あなた」に調査を依頼した場合のみ使用
 - スラッシュコマンドに言及しない（存在を知らない前提）
 - ユーザーが満足したら次工程に進む。次の指示はしない
-{{#if pieceInfo}}
 
-## あなたが作成する指示書の行き先
+## 指示書の提示について
-このタスク指示書は「{{pieceName}}」ピースに渡されます。
+- 対話中は指示書を勝手に提示しない
-ピースの内容: {{pieceDescription}}
+- ユーザーから「指示書を見せて」「いまどんな感じの指示書？」などの要求があった場合のみ、現在の理解を指示書形式で提示
-
+- 最終的な指示書はユーザーに確定される（これはシステムが自動処理）
-指示書は、このピースが期待する形式で作成してください。
-{{/if}}