eyaltoledano/claude-task-master · error

Invalid format: ${options.format}. Valid formats are: text,

Error message

Invalid format: ${options.format}. Valid formats are: text, json

What it means

copyTag enforces that the target tag key is not already present in the tagged data, since tags are object keys and copying into an existing tag would overwrite its tasks. Throwing prevents silent data loss.

Source

Thrown at apps/cli/src/commands/generate.command.ts:95

			this.displayResults(result, options);
		} catch (error: any) {
			hasError = true;
			displayError(error, { skipExit: true });
		} finally {
			await this.cleanup();
		}

		if (hasError) {
			process.exit(1);
		}
	}

	/**
	 * Validate command options
	 */
	private validateOptions(options: GenerateCommandOptions): void {
		if (options.format && !['text', 'json'].includes(options.format)) {
			throw new Error(
				`Invalid format: ${options.format}. Valid formats are: text, json`
			);
		}
	}

	/**
	 * Initialize TmCore
	 */
	private async initializeCore(projectRoot: string): Promise<void> {
		if (!this.tmCore) {
			const resolved = path.resolve(projectRoot);
			this.tmCore = await createTmCore({ projectPath: resolved });
		}
	}

	/**
	 * Generate task files using tm-core
	 */

View on GitHub (pinned to c0c98d367c)

Solutions

1. Choose a unique target tag name
2. Delete or rename the existing target tag first if its contents are disposable
3. Add an existence guard (task-master tags) in scripts before calling copyTag

Example fix

// before
await copyTag(tasksPath, 'backlog', 'sprint-1'); // sprint-1 exists
// after
if (!tagsData['sprint-1']) await copyTag(tasksPath, 'backlog', 'sprint-1');

const data = JSON.parse(fs.readFileSync(tasksPath, 'utf8'));
if (data[targetName] || (data.tags && data.tags[targetName])) {
  throw new Error(`Target tag already exists: ${targetName}`);
}

try {
  await copyTag(tasksPath, source, target);
} catch (e) {
  if (e.message.includes('already exists')) {
    const unique = `${target}-${Date.now()}`;
    return copyTag(tasksPath, source, unique);
  }
  throw e;
}

When it happens

Trigger: Calling copyTag with a targetName that already exists in tasks.json, including re-running the same copy-tag command twice.

Common situations: Idempotent automation scripts re-executing copy-tag; picking a target name that duplicates an existing tag; forgetting a previous copy operation already succeeded.

Related errors

• MFA_VERIFICATION_FAILED
• Failed to initialize services: ${(error as Error).message}
• Failed to fetch tasks from any tag. First error: ${failedTag
• ${authCheck.error}
• VALIDATION_ERROR

AI-assisted analysis of eyaltoledano/claude-task-master@c0c98d367c (2026-08-29). Data as JSON: /api/errors/30ea5cd9e91402b3. Report an issue: GitHub.