What causes "tasksJsonPath is required but was not provided." in eyaltoledano/claude-task-master?

Pass the absolute path to your tasks file, e.g. /path/to/project/.taskmaster/tasks/tasks.json.

MISSING_ARGUMENT

MISSING_ARGUMENT

Error message

tasksJsonPath is required but was not provided.

What it means

updateSubtaskByIdDirect requires the filesystem path to tasks.json (`tasksJsonPath`) because file-based storage needs to know where the task data lives. When the argument is missing/empty it returns MISSING_ARGUMENT immediately without attempting any update. This guard exists because unlike API storage, the file provider cannot infer the path.

Source

Thrown at mcp-server/src/core/direct-functions/update-subtask-by-id.js:48

	const { session } = context;
	// Destructure expected args, including projectRoot and metadata
	const { tasksJsonPath, id, prompt, research, metadata, projectRoot, tag } =
		args;

	const logWrapper = createLogWrapper(log);

	try {
		logWrapper.info(
			`Updating subtask by ID via direct function. ID: ${id}, ProjectRoot: ${projectRoot}`
		);

		// Check if tasksJsonPath was provided
		if (!tasksJsonPath) {
			const errorMessage = 'tasksJsonPath is required but was not provided.';
			logWrapper.error(errorMessage);
			return {
				success: false,
				error: { code: 'MISSING_ARGUMENT', message: errorMessage }
			};
		}

		// Basic validation - ID must be present
		// In API storage, subtask IDs like "HAM-2611" are valid (no dot required)
		// In file storage, subtask IDs must be in format "parentId.subtaskId"
		// The core function handles storage-specific validation
		if (!id || typeof id !== 'string' || !id.trim()) {
			const errorMessage = 'Subtask ID cannot be empty.';
			logWrapper.error(errorMessage);
			return {
				success: false,
				error: { code: 'INVALID_SUBTASK_ID', message: errorMessage }
			};
		}

		// At least prompt or metadata is required (validated in MCP tool layer)
		if (!prompt && !metadata) {

View on GitHub (pinned to c0c98d367c)

Solutions

Pass the absolute path to your tasks file, e.g. /path/to/project/.taskmaster/tasks/tasks.json.
If using API/Supabase storage, ensure the tool/schema variant you call does not require tasksJsonPath, or supply a placeholder per your setup docs.
Check the tool registration in your MCP client so the tasksJsonPath argument is forwarded, not stripped.

Example fix

// before
await updateSubtask({ id: '5.2', prompt: 'Add tests' });
// after
await updateSubtask({ id: '5.2', prompt: 'Add tests', tasksJsonPath: '/proj/.taskmaster/tasks/tasks.json' });

Defensive patterns

Strategy: validation

Validate before calling

if (typeof tasksJsonPath !== 'string' || !tasksJsonPath.trim()) {
  throw new Error('tasksJsonPath is required (path to tasks.json)');
}
if (!fs.existsSync(tasksJsonPath)) throw new Error(`tasks.json not found: ${tasksJsonPath}`);

Type guard

function hasTasksPath(a) { return typeof a.tasksJsonPath === 'string' && a.tasksJsonPath.trim().length > 0; }

Prevention

Build a single config/helper that resolves the tasks.json path once per project
Never pass falsy values through generic argument builders — filter consciously
For API storage, use the appropriate tool variant that does not require the path

When it happens

Trigger: Calling the update-subtask-by-id MCP tool with id/prompt but omitting tasksJsonPath, or passing an empty string; a client wrapper that filters out path arguments it considers secrets.

Common situations: Migrating from API-backed storage where tasksJsonPath was unnecessary; copying example calls from API-mode docs into file-mode setups; agents dropping the path because it looks like boilerplate.

Understand the failure class

Background: Missing required parameter errors: what 'X is required' and 'the required X param is missing' mean, and how to fix them — this error's family across 27 libraries.

Related errors

AI-assisted analysis of eyaltoledano/claude-task-master@c0c98d367c (2026-08-29). Data as JSON: /api/errors/4b9cd003621866e5. Report an issue: GitHub.