Single tool server with a clear verb-noun naming pattern ('get_youtube_transcript'). The tool has a documented description and structured input schema with typed parameters. However, there are significant gaps: output schema is not formally documented (returns raw string), no error classification to guide LLM recovery, no pagination support (not relevant here but missing from output structure), and missing parameter format constraints. The tool handles errors gracefully at runtime but does not provide actionable recovery guidance for LLMs. Error messages are informative but lack classification (retryable vs. user-fixable). The server is READ_ONLY and idempotent, which is good for safety, but these properties are not explicitly annotated in the definition.

• Define a formal output schema: return a structured object with fields like {transcript: string, video_id: string, status: 'success'|'error', error_type: string, message: string} instead of mixed success/error strings.
• Add parameter constraint to video_url description: 'A YouTube video URL in any standard format (e.g. youtube.com/watch?v=..., youtu.be/..., youtube.com/embed/...). The tool will extract the video ID automatically.'
• Classify errors in tool description: 'Retryable errors (network timeout, API rate limit) may be retried. User-fixable errors (invalid URL, disabled transcripts) require user intervention. Unrecoverable errors (video deleted) cannot be resolved.'
• Implement structured error responses: return {transcript: null, status: 'error', error_type: 'invalid_url'|'transcripts_disabled'|'not_found'|'api_error', message: '<actionable error message>'} so LLMs can handle errors programmatically.
• Add readOnlyHint and idempotentHint tool annotations via FastMCP metadata to signal that this tool is safe to call repeatedly.
• Consider returning additional context in success case: {transcript: string, video_id: string, status: 'success', segment_count: int, language: string} to support downstream tool chains.