eyaltoledano/claude-task-master · error · Error

Source tag name is required and must be a string

Error message

Source tag name is required and must be a string

What it means

copyTag() validates that the sourceName argument is a non-empty string before reading tasks.json. This error is thrown when sourceName is missing, null, undefined, empty, or a non-string. The source tag is the tag whose tasks will be duplicated.

Source

Thrown at scripts/modules/task-manager/tag-management.js:1125

	context = {},
	outputFormat = 'text'
) {
	const { mcpLog, projectRoot } = context;
	const { description } = options;

	// Create a consistent logFn object regardless of context
	const logFn = mcpLog || {
		info: (...args) => log('info', ...args),
		warn: (...args) => log('warn', ...args),
		error: (...args) => log('error', ...args),
		debug: (...args) => log('debug', ...args),
		success: (...args) => log('success', ...args)
	};

	try {
		// Validate parameters
		if (!sourceName || typeof sourceName !== 'string') {
			throw new Error('Source tag name is required and must be a string');
		}
		if (!targetName || typeof targetName !== 'string') {
			throw new Error('Target tag name is required and must be a string');
		}

		// Validate target tag name format
		if (!/^[a-zA-Z0-9_-]+$/.test(targetName)) {
			throw new Error(
				'Target tag name can only contain letters, numbers, hyphens, and underscores'
			);
		}

		// Reserved tag names
		const reservedNames = ['master', 'main', 'default'];
		if (reservedNames.includes(targetName.toLowerCase())) {
			throw new Error(`"${targetName}" is a reserved tag name`);
		}

View on GitHub (pinned to c0c98d367c)

Solutions

1. Pass the existing source tag name as the second argument to copyTag as a non-empty string
2. Validate the argument before calling: if (!sourceName || typeof sourceName !== 'string') throw ...
3. Fix argument order/wiring in the calling CLI or MCP layer

Example fix

// before
await copyTag(tasksPath, undefined, 'backup');
// after
await copyTag(tasksPath, 'master', 'backup');

if (!sourceName || typeof sourceName !== 'string') {
  throw new Error('copyTag: sourceName must be a non-empty string');
}

function isNonEmptyString(v) {
  return typeof v === 'string' && v.trim().length > 0;
}

try {
  await copyTag(tasksPath, sourceName, targetName);
} catch (err) {
  if (err.message.includes('Source tag name is required')) {
    console.error(`Invalid source tag argument: ${JSON.stringify(sourceName)}`);
    return;
  }
  throw err;
}

When it happens

Trigger: Calling copyTag(tasksPath, sourceName, targetName) with sourceName omitted or empty; passing a non-string (e.g. number or object); argument-order mistakes so the value lands in options/context.

Common situations: MCP/CLI callers not forwarding the source tag parameter; scripts building the call dynamically with an unset variable; users running the copy command without specifying which tag to copy.

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

• Old tag name is required and must be a string
• New tag name is required and must be a string
• Target tag name is required and must be a string
• MFA_VERIFICATION_FAILED
• Failed to initialize services: ${(error as Error).message}

AI-assisted analysis of eyaltoledano/claude-task-master@c0c98d367c (2026-08-29). Data as JSON: /api/errors/2080ebb80cec2fcc. Report an issue: GitHub.