claude-task-master/mcp-server/src/tools/expand-task.js

/**
 * tools/expand-task.js
 * Tool to expand a task into subtasks
 */

import { z } from 'zod';
import {
	handleApiResult,
	createErrorResponse,
	getProjectRootFromSession
} from './utils.js';
import { expandTaskDirect } from '../core/task-master-core.js';
import { findTasksJsonPath } from '../core/utils/path-utils.js';

/**
 * Register the expand-task tool with the MCP server
 * @param {Object} server - FastMCP server instance
 */
export function registerExpandTaskTool(server) {
	server.addTool({
		name: 'expand_task',
		description: 'Expand a task into subtasks for detailed implementation',
		parameters: z.object({
			id: z.string().describe('ID of task to expand'),
			num: z.string().optional().describe('Number of subtasks to generate'),
			research: z
				.boolean()
				.optional()
				.default(false)
				.describe('Use research role for generation'),
			prompt: z
				.string()
				.optional()
				.describe('Additional context for subtask generation'),
			file: z
				.string()
				.optional()
				.describe(
					'Path to the tasks file relative to project root (e.g., tasks/tasks.json)'
				),
			projectRoot: z
				.string()
				.describe('The directory of the project. Must be an absolute path.'),
			force: z
				.boolean()
				.optional()
				.default(false)
				.describe('Force expansion even if subtasks exist')
		}),
		execute: async (args, { log, session }) => {
			try {
				log.info(`Starting expand-task with args: ${JSON.stringify(args)}`);

				// Get project root from args or session
				const rootFolder =
					args.projectRoot || getProjectRootFromSession(session, log);

				// Ensure project root was determined
				if (!rootFolder) {
					return createErrorResponse(
						'Could not determine project root. Please provide it explicitly or ensure your session contains valid root information.'
					);
				}

				log.info(`Project root resolved to: ${rootFolder}`);

				// Resolve the path to tasks.json using the utility
				let tasksJsonPath;
				try {
					tasksJsonPath = findTasksJsonPath(
						{ projectRoot: rootFolder, file: args.file },
						log
					);
				} catch (error) {
					log.error(`Error finding tasks.json: ${error.message}`);
					return createErrorResponse(
						`Failed to find tasks.json: ${error.message}`
					);
				}

				// Call direct function with only session in the context, not reportProgress
				// Use the pattern recommended in the MCP guidelines
				const result = await expandTaskDirect(
					{
						// Pass the explicitly resolved path
						tasksJsonPath: tasksJsonPath,
						// Pass other relevant args
						id: args.id,
						num: args.num,
						research: args.research,
						prompt: args.prompt,
						force: args.force // Need to add force to parameters
					},
					log,
					{ session }
				); // Only pass session, NOT reportProgress

				// Return the result
				return handleApiResult(result, log, 'Error expanding task');
			} catch (error) {
				log.error(`Error in expand task tool: ${error.message}`);
				return createErrorResponse(error.message);
			}
		}
	});
}