feat(loop): add streaming output mode with --stream flag (#1605)

.changeset/cuddly-wings-drop.md

@@ -0,0 +1,9 @@
+---
+"task-master-ai": minor
+---
+
+Add verbose output mode to loop command with `--verbose` flag
+
+- New `-v, --verbose` flag shows Claude's work in real-time (thinking, tool calls) rather than waiting until the iteration completes
+- New `--no-output` flag excludes full Claude output from iteration results to save memory
+- Improved error handling with proper validation for incompatible options (verbose + sandbox)

apps/cli/src/commands/loop.command.spec.ts

@@ -91,6 +91,9 @@ describe('LoopCommand', () => {
 				getStorageType: vi.fn().mockReturnValue('local'),
 				getNext: vi.fn().mockResolvedValue({ id: '1', title: 'Test Task' }),
 				getCount: vi.fn().mockResolvedValue(0)
+			},
+			auth: {
+				getContext: vi.fn().mockReturnValue(null)
 			}
 		};
 

apps/cli/src/commands/loop.command.ts

@@ -5,6 +5,8 @@
 import path from 'node:path';
 import {
 	type LoopConfig,
+	type LoopIteration,
+	type LoopOutputCallbacks,
 	type LoopResult,
 	PRESET_NAMES,
 	type TmCore,
@@ -23,6 +25,8 @@ export interface LoopCommandOptions {
 	tag?: string;
 	project?: string;
 	sandbox?: boolean;
+	output?: boolean;
+	verbose?: boolean;
 }
 
 export class LoopCommand extends Command {
@@ -49,6 +53,11 @@ export class LoopCommand extends Command {
 				'Project root directory (auto-detected if not provided)'
 			)
 			.option('--sandbox', 'Run Claude in Docker sandbox mode')
+			.option(
+				'--no-output',
+				'Exclude full Claude output from iteration results'
+			)
+			.option('-v, --verbose', "Show Claude's work in real-time")
 			.action((options: LoopCommandOptions) => this.execute(options));
 	}
 
@@ -109,12 +118,21 @@ export class LoopCommand extends Command {
 			}
 			console.log();
 
+			// Auto-detect brief name from auth context (if available)
+			const briefName = this.tmCore.auth.getContext()?.briefName;
+
 			const config: Partial<LoopConfig> = {
 				iterations,
 				prompt,
 				progressFile,
 				tag: options.tag,
-				sandbox: options.sandbox
+				sandbox: options.sandbox,
+				// CLI defaults to including output (users typically want to see it)
+				// Domain defaults to false (library consumers opt-in explicitly)
+				includeOutput: options.output ?? true,
+				verbose: options.verbose ?? false,
+				brief: briefName,
+				callbacks: this.createOutputCallbacks()
 			};
 
 			const result = await this.tmCore.loop.run(config);
@@ -161,6 +179,47 @@ export class LoopCommand extends Command {
 		}
 	}
 
+	private createOutputCallbacks(): LoopOutputCallbacks {
+		return {
+			onIterationStart: (iteration: number, total: number) => {
+				console.log();
+				console.log(chalk.cyan(`━━━ Iteration ${iteration} of ${total} ━━━`));
+			},
+			onText: (text: string) => {
+				console.log(text);
+			},
+			onToolUse: (toolName: string) => {
+				console.log(chalk.dim(`  → ${toolName}`));
+			},
+			onError: (message: string, severity?: 'warning' | 'error') => {
+				if (severity === 'warning') {
+					console.error(chalk.yellow(`[Loop Warning] ${message}`));
+				} else {
+					console.error(chalk.red(`[Loop Error] ${message}`));
+				}
+			},
+			onStderr: (iteration: number, text: string) => {
+				process.stderr.write(chalk.dim(`[Iteration ${iteration}] `) + text);
+			},
+			onOutput: (output: string) => {
+				console.log(output);
+			},
+			onIterationEnd: (iteration: LoopIteration) => {
+				const statusColor =
+					iteration.status === 'success'
+						? chalk.green
+						: iteration.status === 'error'
+							? chalk.red
+							: chalk.yellow;
+				console.log(
+					statusColor(
+						`  Iteration ${iteration.iteration} completed: ${iteration.status}`
+					)
+				);
+			}
+		};
+	}
+
 	private displayResult(result: LoopResult): void {
 		console.log();
 		console.log(chalk.bold('Loop Complete'));
@@ -168,6 +227,9 @@ export class LoopCommand extends Command {
 		console.log(`Total iterations: ${result.totalIterations}`);
 		console.log(`Tasks completed: ${result.tasksCompleted}`);
 		console.log(`Final status: ${this.formatStatus(result.finalStatus)}`);
+		if (result.errorMessage) {
+			console.log(chalk.red(`Error: ${result.errorMessage}`));
+		}
 	}
 
 	private formatStatus(status: LoopResult['finalStatus']): string {

packages/tm-core/src/index.ts

@@ -155,7 +155,8 @@ export type {
 	LoopPreset,
 	LoopConfig,
 	LoopIteration,
-	LoopResult
+	LoopResult,
+	LoopOutputCallbacks
 } from './modules/loop/index.js';
 export { LoopDomain, PRESET_NAMES } from './modules/loop/index.js';
 

packages/tm-core/src/modules/loop/index.ts

@@ -15,7 +15,8 @@ export type {
 	LoopPreset,
 	LoopConfig,
 	LoopIteration,
-	LoopResult
+	LoopResult,
+	LoopOutputCallbacks
 } from './types.js';
 
 // Presets - content and helpers

packages/tm-core/src/modules/loop/loop-domain.ts

@@ -190,7 +190,11 @@ export class LoopDomain {
 				path.join(this.projectRoot, '.taskmaster', 'progress.txt'),
 			sleepSeconds: partial.sleepSeconds ?? 5,
 			tag: partial.tag,
-			sandbox: partial.sandbox ?? false
+			sandbox: partial.sandbox ?? false,
+			includeOutput: partial.includeOutput ?? false,
+			verbose: partial.verbose ?? false,
+			brief: partial.brief,
+			callbacks: partial.callbacks
 		};
 	}
 }

packages/tm-core/src/modules/loop/presets/__snapshots__/presets.spec.ts.snap

@@ -3,7 +3,7 @@
 exports[`Preset Snapshots > default preset matches snapshot 1`] = `
 "SETUP: If task-master command not found, run: npm i -g task-master-ai
 
-TASK: Implement ONE task/subtask from the Task Master backlog.
+TASK: Implement ONE task/subtask from the Taskmaster backlog.
 
 PROCESS:
 1. Run task-master next (or use MCP) to get the next available task/subtask.
@@ -26,7 +26,7 @@ IMPORTANT:
 `;
 
 exports[`Preset Snapshots > duplication preset matches snapshot 1`] = `
-"# Task Master Loop - Duplication
+"# Taskmaster Loop - Duplication
 
 Find duplicated code and refactor into shared utilities. ONE refactor per session.
 
@@ -60,7 +60,7 @@ Find duplicated code and refactor into shared utilities. ONE refactor per sessio
 `;
 
 exports[`Preset Snapshots > entropy preset matches snapshot 1`] = `
-"# Task Master Loop - Entropy (Code Smells)
+"# Taskmaster Loop - Entropy (Code Smells)
 
 Find code smells and clean them up. ONE cleanup per session.
 
@@ -102,7 +102,7 @@ Find code smells and clean them up. ONE cleanup per session.
 `;
 
 exports[`Preset Snapshots > linting preset matches snapshot 1`] = `
-"# Task Master Loop - Linting
+"# Taskmaster Loop - Linting
 
 Fix lint errors and type errors one by one. ONE fix per session.
 
@@ -136,7 +136,7 @@ Fix lint errors and type errors one by one. ONE fix per session.
 `;
 
 exports[`Preset Snapshots > test-coverage preset matches snapshot 1`] = `
-"# Task Master Loop - Test Coverage
+"# Taskmaster Loop - Test Coverage
 
 Find uncovered code and write meaningful tests. ONE test per session.
 

packages/tm-core/src/modules/loop/presets/default.ts

@@ -1,10 +1,10 @@
 /**
- * Default preset for Task Master loop - general task completion
+ * Default preset for Taskmaster loop - general task completion
  * Matches the structure of scripts/loop.sh prompt
  */
 export const DEFAULT_PRESET = `SETUP: If task-master command not found, run: npm i -g task-master-ai
 
-TASK: Implement ONE task/subtask from the Task Master backlog.
+TASK: Implement ONE task/subtask from the Taskmaster backlog.
 
 PROCESS:
 1. Run task-master next (or use MCP) to get the next available task/subtask.

packages/tm-core/src/modules/loop/presets/duplication.ts

@@ -1,7 +1,7 @@
 /**
- * Duplication preset for Task Master loop - code deduplication
+ * Duplication preset for Taskmaster loop - code deduplication
  */
-export const DUPLICATION_PRESET = `# Task Master Loop - Duplication
+export const DUPLICATION_PRESET = `# Taskmaster Loop - Duplication
 
 Find duplicated code and refactor into shared utilities. ONE refactor per session.
 

packages/tm-core/src/modules/loop/presets/entropy.ts

@@ -2,7 +2,7 @@
  * @fileoverview Entropy (Code Smells) preset for loop module
  */
 
-export const ENTROPY_PRESET = `# Task Master Loop - Entropy (Code Smells)
+export const ENTROPY_PRESET = `# Taskmaster Loop - Entropy (Code Smells)
 
 Find code smells and clean them up. ONE cleanup per session.
 

packages/tm-core/src/modules/loop/presets/linting.ts

@@ -1,7 +1,7 @@
 /**
- * Linting preset for Task Master loop - fix lint and type errors
+ * Linting preset for Taskmaster loop - fix lint and type errors
  */
-export const LINTING_PRESET = `# Task Master Loop - Linting
+export const LINTING_PRESET = `# Taskmaster Loop - Linting
 
 Fix lint errors and type errors one by one. ONE fix per session.
 

packages/tm-core/src/modules/loop/presets/test-coverage.ts

@@ -1,7 +1,7 @@
 /**
- * Test coverage preset for Task Master loop - writing meaningful tests
+ * Test coverage preset for Taskmaster loop - writing meaningful tests
  */
-export const TEST_COVERAGE_PRESET = `# Task Master Loop - Test Coverage
+export const TEST_COVERAGE_PRESET = `# Taskmaster Loop - Test Coverage
 
 Find uncovered code and write meaningful tests. ONE test per session.
 

packages/tm-core/src/modules/loop/services/loop.service.spec.ts

@@ -394,7 +394,7 @@ describe('LoopService', () => {
 				// Uses appendFile instead of writeFile to preserve existing progress
 				expect(fsPromises.appendFile).toHaveBeenCalledWith(
 					'/test/progress.txt',
-					expect.stringContaining('# Task Master Loop Progress'),
+					expect.stringContaining('# Taskmaster Loop Progress'),
 					'utf-8'
 				);
 			});
@@ -619,12 +619,13 @@ describe('LoopService', () => {
 			expect(header).toContain('@/test/progress.txt');
 		});
 
-		it('should include tasks file reference', () => {
+		it('should NOT include tasks file reference (preset controls task source)', () => {
 			const header = buildContextHeader(
 				{ iterations: 1, progressFile: '/test/progress.txt' },
 				1
 			);
-			expect(header).toContain('@.taskmaster/tasks/tasks.json');
+			// tasks.json intentionally excluded - let preset control task source to avoid confusion
+			expect(header).not.toContain('tasks.json');
 		});
 
 		it('should include tag filter when provided', () => {

packages/tm-core/src/modules/loop/services/loop.service.ts

@@ -2,13 +2,15 @@
  * @fileoverview Loop Service - Orchestrates running Claude Code iterations (sandbox or CLI mode)
  */
 
-import { spawnSync } from 'node:child_process';
+import { spawn, spawnSync } from 'node:child_process';
 import { appendFile, mkdir, readFile } from 'node:fs/promises';
 import path from 'node:path';
+import { getLogger } from '../../../common/logger/index.js';
 import { PRESETS, isPreset as checkIsPreset } from '../presets/index.js';
 import type {
 	LoopConfig,
 	LoopIteration,
+	LoopOutputCallbacks,
 	LoopPreset,
 	LoopResult
 } from '../types.js';
@@ -19,6 +21,7 @@ export interface LoopServiceOptions {
 
 export class LoopService {
 	private readonly projectRoot: string;
+	private readonly logger = getLogger('LoopService');
 	private _isRunning = false;
 
 	constructor(options: LoopServiceOptions) {
@@ -109,6 +112,20 @@ export class LoopService {
 
 	/** Run a loop with the given configuration */
 	async run(config: LoopConfig): Promise<LoopResult> {
+		// Validate incompatible options early - fail once, not per iteration
+		if (config.verbose && config.sandbox) {
+			const errorMsg =
+				'Verbose mode is not supported with sandbox mode. Use --verbose without --sandbox, or remove --verbose.';
+			this.reportError(config.callbacks, errorMsg);
+			return {
+				iterations: [],
+				totalIterations: 0,
+				tasksCompleted: 0,
+				finalStatus: 'error',
+				errorMessage: errorMsg
+			};
+		}
+
 		this._isRunning = true;
 		const iterations: LoopIteration[] = [];
 		let tasksCompleted = 0;
@@ -116,18 +133,23 @@ export class LoopService {
 		await this.initProgressFile(config);
 
 		for (let i = 1; i <= config.iterations && this._isRunning; i++) {
-			// Show iteration header
+			// Notify presentation layer of iteration start
-			console.log();
+			config.callbacks?.onIterationStart?.(i, config.iterations);
-			console.log(`━━━ Iteration ${i} of ${config.iterations} ━━━`);
 
 			const prompt = await this.buildPrompt(config, i);
-			const iteration = this.executeIteration(
+			const iteration = await this.executeIteration(
 				prompt,
 				i,
-				config.sandbox ?? false
+				config.sandbox ?? false,
+				config.includeOutput ?? false,
+				config.verbose ?? false,
+				config.callbacks
 			);
 			iterations.push(iteration);
 
+			// Notify presentation layer of iteration completion
+			config.callbacks?.onIterationEnd?.(iteration);
+
 			// Check for early exit conditions
 			if (iteration.status === 'complete') {
 				return this.finalize(
@@ -177,21 +199,41 @@ export class LoopService {
 		return result;
 	}
 
+	/**
+	 * Report an error via callback if provided, otherwise log to the logger.
+	 * Ensures errors are never silently swallowed when callbacks aren't configured.
+	 */
+	private reportError(
+		callbacks: LoopOutputCallbacks | undefined,
+		message: string,
+		severity: 'warning' | 'error' = 'error'
+	): void {
+		if (callbacks?.onError) {
+			callbacks.onError(message, severity);
+		} else if (severity === 'warning') {
+			this.logger.warn(message);
+		} else {
+			this.logger.error(message);
+		}
+	}
+
 	private async initProgressFile(config: LoopConfig): Promise<void> {
 		await mkdir(path.dirname(config.progressFile), { recursive: true });
-		const tagLine = config.tag ? `# Tag: ${config.tag}\n` : '';
+		const lines = [
+			'# Taskmaster Loop Progress',
+			`# Started: ${new Date().toISOString()}`,
+			...(config.brief ? [`# Brief: ${config.brief}`] : []),
+			`# Preset: ${config.prompt}`,
+			`# Max Iterations: ${config.iterations}`,
+			...(config.tag ? [`# Tag: ${config.tag}`] : []),
+			'',
+			'---',
+			''
+		];
 		// Append to existing progress file instead of overwriting
 		await appendFile(
 			config.progressFile,
-			`
+			'\n' + lines.join('\n') + '\n',
-# Task Master Loop Progress
-# Started: ${new Date().toISOString()}
-# Preset: ${config.prompt}
-# Max Iterations: ${config.iterations}
-${tagLine}
----
-
-`,
 			'utf-8'
 		);
 	}
@@ -230,7 +272,8 @@ ${tagLine}
 
 	private buildContextHeader(config: LoopConfig, iteration: number): string {
 		const tagInfo = config.tag ? ` (tag: ${config.tag})` : '';
-		return `@${config.progressFile} @.taskmaster/tasks/tasks.json @CLAUDE.md
+		// Note: tasks.json reference removed - let the preset control task source to avoid confusion
+		return `@${config.progressFile} @CLAUDE.md
 
 Loop iteration ${iteration} of ${config.iterations}${tagInfo}`;
 	}
@@ -262,63 +305,56 @@ Loop iteration ${iteration} of ${config.iterations}${tagInfo}`;
 		return { status: 'success' };
 	}
 
-	private executeIteration(
+	private async executeIteration(
 		prompt: string,
 		iterationNum: number,
-		sandbox: boolean
+		sandbox: boolean,
-	): LoopIteration {
+		includeOutput = false,
+		verbose = false,
+		callbacks?: LoopOutputCallbacks
+	): Promise<LoopIteration> {
 		const startTime = Date.now();
-
-		// Use docker sandbox or plain claude based on config
 		const command = sandbox ? 'docker' : 'claude';
-		const args = sandbox
-			? ['sandbox', 'run', 'claude', '-p', prompt]
-			: ['-p', prompt, '--dangerously-skip-permissions'];
 
+		if (verbose) {
+			return this.executeVerboseIteration(
+				prompt,
+				iterationNum,
+				command,
+				sandbox,
+				includeOutput,
+				startTime,
+				callbacks
+			);
+		}
+
+		const args = this.buildCommandArgs(prompt, sandbox, false);
 		const result = spawnSync(command, args, {
 			cwd: this.projectRoot,
 			encoding: 'utf-8',
-			maxBuffer: 50 * 1024 * 1024, // 50MB buffer
+			maxBuffer: 50 * 1024 * 1024,
 			stdio: ['inherit', 'pipe', 'pipe']
 		});
 
-		// Check for spawn-level errors (command not found, permission denied, etc.)
 		if (result.error) {
-			const code = (result.error as NodeJS.ErrnoException).code;
+			const errorMessage = this.formatCommandError(
-			let errorMessage: string;
+				result.error,
-
+				command,
-			if (code === 'ENOENT') {
+				sandbox
-				errorMessage = sandbox
+			);
-					? 'Docker is not installed. Install Docker Desktop to use --sandbox mode.'
+			this.reportError(callbacks, errorMessage);
-					: 'Claude CLI is not installed. Install with: npm install -g @anthropic-ai/claude-code';
+			return this.createErrorIteration(iterationNum, startTime, errorMessage);
-			} else if (code === 'EACCES') {
-				errorMessage = `Permission denied executing '${command}'`;
-			} else {
-				errorMessage = `Failed to execute '${command}': ${result.error.message}`;
-			}
-
-			console.error(`[Loop Error] ${errorMessage}`);
-			return {
-				iteration: iterationNum,
-				status: 'error',
-				duration: Date.now() - startTime,
-				message: errorMessage
-			};
 		}
 
 		const output = (result.stdout || '') + (result.stderr || '');
+		if (output) {
+			callbacks?.onOutput?.(output);
+		}
 
-		// Print output to console (spawnSync with pipe captures but doesn't display)
-		if (output) console.log(output);
-
-		// Handle null status (spawn failed but no error object - shouldn't happen but be safe)
 		if (result.status === null) {
-			return {
+			const errorMsg = 'Command terminated abnormally (no exit code)';
-				iteration: iterationNum,
+			this.reportError(callbacks, errorMsg);
-				status: 'error',
+			return this.createErrorIteration(iterationNum, startTime, errorMsg);
-				duration: Date.now() - startTime,
-				message: 'Command terminated abnormally (no exit code)'
-			};
 		}
 
 		const { status, message } = this.parseCompletion(output, result.status);
@@ -326,7 +362,282 @@ Loop iteration ${iteration} of ${config.iterations}${tagInfo}`;
 			iteration: iterationNum,
 			status,
 			duration: Date.now() - startTime,
+			message,
+			...(includeOutput && { output })
+		};
+	}
+
+	/**
+	 * Execute an iteration with verbose output (shows Claude's work in real-time).
+	 * Uses Claude's stream-json format to display assistant messages as they arrive.
+	 * @param prompt - The prompt to send to Claude
+	 * @param iterationNum - Current iteration number (1-indexed)
+	 * @param command - The command to execute ('claude' or 'docker')
+	 * @param sandbox - Whether running in Docker sandbox mode
+	 * @param includeOutput - Whether to include full output in the result
+	 * @param startTime - Timestamp when iteration started (for duration calculation)
+	 * @param callbacks - Optional callbacks for presentation layer output
+	 * @returns Promise resolving to the iteration result
+	 */
+	private executeVerboseIteration(
+		prompt: string,
+		iterationNum: number,
+		command: string,
+		sandbox: boolean,
+		includeOutput: boolean,
+		startTime: number,
+		callbacks?: LoopOutputCallbacks
+	): Promise<LoopIteration> {
+		const args = this.buildCommandArgs(prompt, sandbox, true);
+
+		return new Promise((resolve) => {
+			// Prevent multiple resolutions from race conditions between error/close events
+			let isResolved = false;
+			const resolveOnce = (result: LoopIteration): void => {
+				if (!isResolved) {
+					isResolved = true;
+					resolve(result);
+				}
+			};
+
+			const child = spawn(command, args, {
+				cwd: this.projectRoot,
+				stdio: ['inherit', 'pipe', 'pipe']
+			});
+
+			// Track stdout completion to handle race between data and close events
+			let stdoutEnded = false;
+			let finalResult = '';
+			let buffer = '';
+
+			const processLine = (line: string): void => {
+				if (!line.startsWith('{')) return;
+
+				try {
+					const event = JSON.parse(line);
+
+					// Validate event structure before accessing properties
+					if (!this.isValidStreamEvent(event)) {
+						return;
+					}
+
+					this.handleStreamEvent(event, callbacks);
+
+					// Capture final result for includeOutput feature
+					if (event.type === 'result') {
+						finalResult = typeof event.result === 'string' ? event.result : '';
+					}
+				} catch (error) {
+					// Log malformed JSON for debugging (non-JSON lines like system output are expected)
+					if (line.trim().startsWith('{')) {
+						const parseError = `Failed to parse JSON event: ${error instanceof Error ? error.message : 'Unknown error'}. Line: ${line.substring(0, 100)}...`;
+						this.reportError(callbacks, parseError, 'warning');
+					}
+				}
+			};
+
+			// Handle null stdout (shouldn't happen with pipe, but be defensive)
+			if (!child.stdout) {
+				resolveOnce(
+					this.createErrorIteration(
+						iterationNum,
+						startTime,
+						'Failed to capture stdout from child process'
+					)
+				);
+				return;
+			}
+
+			child.stdout.on('data', (data: Buffer) => {
+				try {
+					const lines = this.processBufferedLines(
+						buffer,
+						data.toString('utf-8')
+					);
+					buffer = lines.remaining;
+					for (const line of lines.complete) {
+						processLine(line);
+					}
+				} catch (error) {
+					this.reportError(
+						callbacks,
+						`Failed to process stdout data: ${error instanceof Error ? error.message : 'Unknown error'}`,
+						'warning'
+					);
+				}
+			});
+
+			child.stdout.on('end', () => {
+				stdoutEnded = true;
+				// Process any remaining buffer when stdout ends
+				if (buffer) {
+					processLine(buffer);
+					buffer = '';
+				}
+			});
+
+			child.stderr?.on('data', (data: Buffer) => {
+				const stderrText = data.toString('utf-8');
+				callbacks?.onStderr?.(iterationNum, stderrText);
+			});
+
+			child.on('error', (error: NodeJS.ErrnoException) => {
+				const errorMessage = this.formatCommandError(error, command, sandbox);
+				this.reportError(callbacks, errorMessage);
+
+				// Cleanup: remove listeners and kill process if still running
+				child.stdout?.removeAllListeners();
+				child.stderr?.removeAllListeners();
+				if (!child.killed) {
+					try {
+						child.kill('SIGTERM');
+					} catch {
+						// Process may have already exited
+					}
+				}
+
+				resolveOnce(
+					this.createErrorIteration(iterationNum, startTime, errorMessage)
+				);
+			});
+
+			child.on('close', (exitCode: number | null) => {
+				// Process remaining buffer only if stdout hasn't already ended
+				if (!stdoutEnded && buffer) {
+					processLine(buffer);
+				}
+
+				if (exitCode === null) {
+					const errorMsg = 'Command terminated abnormally (no exit code)';
+					this.reportError(callbacks, errorMsg);
+					resolveOnce(
+						this.createErrorIteration(iterationNum, startTime, errorMsg)
+					);
+					return;
+				}
+
+				const { status, message } = this.parseCompletion(finalResult, exitCode);
+				resolveOnce({
+					iteration: iterationNum,
+					status,
+					duration: Date.now() - startTime,
+					message,
+					...(includeOutput && { output: finalResult })
+				});
+			});
+		});
+	}
+
+	/**
+	 * Validate that a parsed JSON object has the expected stream event structure.
+	 */
+	private isValidStreamEvent(event: unknown): event is {
+		type: string;
+		message?: {
+			content?: Array<{ type: string; text?: string; name?: string }>;
+		};
+		result?: string;
+	} {
+		if (!event || typeof event !== 'object') {
+			return false;
+		}
+
+		const e = event as Record<string, unknown>;
+		if (!('type' in e) || typeof e.type !== 'string') {
+			return false;
+		}
+
+		// Validate message structure if present
+		if ('message' in e && e.message !== undefined) {
+			if (typeof e.message !== 'object' || e.message === null) {
+				return false;
+			}
+			const msg = e.message as Record<string, unknown>;
+			if ('content' in msg && !Array.isArray(msg.content)) {
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	private buildCommandArgs(
+		prompt: string,
+		sandbox: boolean,
+		verbose: boolean
+	): string[] {
+		if (sandbox) {
+			return ['sandbox', 'run', 'claude', '-p', prompt];
+		}
+
+		const args = ['-p', prompt, '--dangerously-skip-permissions'];
+		if (verbose) {
+			// Use stream-json format to show Claude's work in real-time
+			args.push('--output-format', 'stream-json', '--verbose');
+		}
+		return args;
+	}
+
+	private formatCommandError(
+		error: NodeJS.ErrnoException,
+		command: string,
+		sandbox: boolean
+	): string {
+		if (error.code === 'ENOENT') {
+			return sandbox
+				? 'Docker is not installed. Install Docker Desktop to use --sandbox mode.'
+				: 'Claude CLI is not installed. Install with: npm install -g @anthropic-ai/claude-code';
+		}
+
+		if (error.code === 'EACCES') {
+			return `Permission denied executing '${command}'`;
+		}
+
+		return `Failed to execute '${command}': ${error.message}`;
+	}
+
+	private createErrorIteration(
+		iterationNum: number,
+		startTime: number,
+		message: string
+	): LoopIteration {
+		return {
+			iteration: iterationNum,
+			status: 'error',
+			duration: Date.now() - startTime,
 			message
 		};
 	}
+
+	private handleStreamEvent(
+		event: {
+			type: string;
+			message?: {
+				content?: Array<{ type: string; text?: string; name?: string }>;
+			};
+		},
+		callbacks?: LoopOutputCallbacks
+	): void {
+		if (event.type !== 'assistant' || !event.message?.content) return;
+
+		for (const block of event.message.content) {
+			if (block.type === 'text' && block.text) {
+				callbacks?.onText?.(block.text);
+			} else if (block.type === 'tool_use' && block.name) {
+				callbacks?.onToolUse?.(block.name);
+			}
+		}
+	}
+
+	private processBufferedLines(
+		buffer: string,
+		newData: string
+	): { complete: string[]; remaining: string } {
+		const combined = buffer + newData;
+		const lines = combined.split('\n');
+		return {
+			complete: lines.slice(0, -1),
+			remaining: lines[lines.length - 1]
+		};
+	}
 }

packages/tm-core/src/modules/loop/types.ts

@@ -12,6 +12,33 @@ export type LoopPreset =
 	| 'duplication'
 	| 'entropy';
 
+/**
+ * Output callbacks for loop execution.
+ * These allow the caller (CLI/MCP) to handle presentation while
+ * the service stays focused on business logic.
+ *
+ * Callback modes:
+ * - `onIterationStart`, `onIterationEnd`, `onError`, `onStderr`: Called in both verbose and non-verbose modes
+ * - `onText`, `onToolUse`: Called only in VERBOSE mode (--verbose flag)
+ * - `onOutput`: Called only in NON-VERBOSE mode (default)
+ */
+export interface LoopOutputCallbacks {
+	/** Called at the start of each iteration (both modes) */
+	onIterationStart?: (iteration: number, total: number) => void;
+	/** Called when Claude outputs text (VERBOSE MODE ONLY) */
+	onText?: (text: string) => void;
+	/** Called when Claude invokes a tool (VERBOSE MODE ONLY) */
+	onToolUse?: (toolName: string) => void;
+	/** Called when an error occurs (both modes) */
+	onError?: (message: string, severity?: 'warning' | 'error') => void;
+	/** Called for stderr output (both modes) */
+	onStderr?: (iteration: number, text: string) => void;
+	/** Called when non-verbose iteration completes with output (NON-VERBOSE MODE ONLY) */
+	onOutput?: (output: string) => void;
+	/** Called at the end of each iteration with the result (both modes) */
+	onIterationEnd?: (iteration: LoopIteration) => void;
+}
+
 /**
  * Configuration options for a loop execution
  */
@@ -28,6 +55,39 @@ export interface LoopConfig {
 	tag?: string;
 	/** Run Claude in Docker sandbox mode (default: false) */
 	sandbox?: boolean;
+	/**
+	 * Include full Claude output in iteration results (default: false)
+	 *
+	 * When true: `LoopIteration.output` will contain full stdout+stderr text
+	 * When false: `LoopIteration.output` will be undefined (saves memory)
+	 *
+	 * Can be combined with `verbose=true` to both display and capture output.
+	 * Note: Output can be large (up to 50MB per iteration).
+	 */
+	includeOutput?: boolean;
+	/**
+	 * Show Claude's work in real-time instead of just the result (default: false)
+	 *
+	 * When true: Output appears as Claude generates it (shows thinking, tool calls)
+	 * When false: Output appears only after iteration completes
+	 *
+	 * Independent of `includeOutput` - controls display timing, not capture.
+	 * Note: NOT compatible with `sandbox=true` (will return error).
+	 */
+	verbose?: boolean;
+	/**
+	 * Brief title describing the current initiative/goal (optional)
+	 *
+	 * If provided, included in the progress file header to give Claude
+	 * context about the bigger picture across iterations.
+	 * Example: "Implement streaming output for loop command"
+	 */
+	brief?: string;
+	/**
+	 * Output callbacks for presentation layer (CLI/MCP).
+	 * If not provided, the service runs silently (no console output).
+	 */
+	callbacks?: LoopOutputCallbacks;
 }
 
 /**
@@ -44,6 +104,15 @@ export interface LoopIteration {
 	message?: string;
 	/** Duration of this iteration in milliseconds */
 	duration?: number;
+	/**
+	 * Full Claude output text
+	 *
+	 * ONLY present when `LoopConfig.includeOutput=true`.
+	 * Contains concatenated stdout and stderr from Claude CLI execution.
+	 * May include ANSI color codes and tool call output.
+	 * Can be large - use `includeOutput=false` to save memory.
+	 */
+	output?: string;
 }
 
 /**
@@ -58,4 +127,6 @@ export interface LoopResult {
 	tasksCompleted: number;
 	/** Final status of the loop */
 	finalStatus: 'all_complete' | 'max_iterations' | 'blocked' | 'error';
+	/** Error message when finalStatus is 'error' (optional) */
+	errorMessage?: string;
 }

tests/setup.js

@@ -51,3 +51,16 @@ if (process.env.SILENCE_CONSOLE === 'true') {
 		error: () => {}
 	};
 }
+
+// Clean up signal-exit listeners after all tests to prevent open handle warnings
+// This is needed because packages like proper-lockfile register signal handlers
+afterAll(async () => {
+	// Give any pending async operations time to complete
+	await new Promise((resolve) => setImmediate(resolve));
+
+	// Clean up any registered signal handlers from signal-exit
+	const listeners = ['SIGINT', 'SIGTERM', 'SIGHUP'];
+	for (const signal of listeners) {
+		process.removeAllListeners(signal);
+	}
+});