Single tool with adequate naming and clear purpose, but parameter descriptions are minimal and output schema is not documented. The tool follows basic structure but lacks the depth expected in production-grade agents. Schema validation is present but sparse. Error handling returns structured responses but lacks actionable recovery guidance.

• Add explicit output schema documentation: specify that successful responses return {transcript: [{start: string, end: string, text: string}], language: string, requested_language: string} and failure responses return {error: string, details: string, attempted_languages: string[]}
• Enhance parameter descriptions: document language fallback behavior explicitly. Example: 'ISO 639-1 language code (en, fr, es, etc). If requested language unavailable, tool will attempt fallback sequence: requested_language → en → fr → es → de. Returns actual_language in response.'
• Implement categorized error responses with recovery hints. On 'No subtitles' error: suggest 'Subtitles may not be available for this video. Check YouTube UI for caption availability or try a different video.' On timeout: suggest 'Request exceeded 30s. Video may be very long or network unstable. Try again or request shorter clip.'
• Add input validation with descriptive errors: reject invalid URLs immediately with pattern guidance rather than generic 'Invalid YouTube URL'
• Add toolAnnotations to FastMCP decorator: @mcp.tool(description='...', annotations={'readOnlyHint': true, 'idempotentHint': true}) to signal this is a read-only, safe-to-retry operation