What causes "tasksJsonPath is required" in eyaltoledano/claude-task-master?

Pass tasksJsonPath pointing to the project's tasks.json file.

MISSING_ARGUMENT

MISSING_ARGUMENT

Error message

tasksJsonPath is required

What it means

addSubtaskDirect, the MCP direct-function wrapper for add-subtask, requires tasksJsonPath to locate the task file it will mutate. If missing or empty, it returns a structured MISSING_ARGUMENT failure and logs the misuse, mirroring the validation pattern of addDependencyDirect.

Source

Thrown at mcp-server/src/core/direct-functions/add-subtask.js:52

		title,
		description,
		details,
		status,
		dependencies: dependenciesStr,
		skipGenerate,
		projectRoot,
		tag
	} = args;
	try {
		log.info(`Adding subtask with args: ${JSON.stringify(args)}`);

		// Check if tasksJsonPath was provided
		if (!tasksJsonPath) {
			log.error('addSubtaskDirect called without tasksJsonPath');
			return {
				success: false,
				error: {
					code: 'MISSING_ARGUMENT',
					message: 'tasksJsonPath is required'
				}
			};
		}

		if (!id) {
			return {
				success: false,
				error: {
					code: 'INPUT_VALIDATION_ERROR',
					message: 'Parent task ID is required'
				}
			};
		}

		// Either taskId or title must be provided
		if (!taskId && !title) {
			return {

View on GitHub (pinned to c0c98d367c)

Solutions

Pass tasksJsonPath pointing to the project's tasks.json file.
Start/configure the MCP server in the directory containing tasks.json so defaults resolve.
Make the client send all required arguments per the add_subtask tool schema.
Check for empty-string paths produced by template placeholders that were never filled in.

Example fix

// before
await addSubtaskDirect({ id: '1', title: 'Write tests' });
// after
await addSubtaskDirect({
  tasksJsonPath: '/path/to/project/tasks.json',
  id: '1',
  title: 'Write tests'
});

Defensive patterns

Strategy: validation

Validate before calling

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

Type guard

function hasTasksJsonPath(args) {
  return typeof args?.tasksJsonPath === 'string' && args.tasksJsonPath.length > 0;
}

Try / catch

if (!hasTasksJsonPath(args)) {
  return { success: false, error: { code: 'MISSING_ARGUMENT', message: 'tasksJsonPath is required' } };
}

Prevention

Pass tasksJsonPath explicitly in every add_subtask call, even when the server has a default.
Store the path in a single config constant to avoid drift across calls.
Verify existence with fs.existsSync before invocation.
Re-check the path after workspace renames or monorepo restructuring.

When it happens

Trigger: Calling the add_subtask MCP tool without a tasksJsonPath argument; the MCP session's path resolution returns undefined because the tool is invoked outside a project directory; an empty-string path passed by a generated client.

Common situations: AI clients invoking add_subtask with only the subtask fields and forgetting the file path; monorepo setups where tasks.json lives in a subdirectory not covered by default resolution; renamed workspace roots after a refactor.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

AI-assisted analysis of eyaltoledano/claude-task-master@c0c98d367c (2026-08-29). Data as JSON: /api/errors/31de4b99dc0e64bc. Report an issue: GitHub.