The server defines 4 tools with complete JSON schemas and reasonable descriptions. However, several critical gaps reduce quality: (1) Tool names follow the verb_noun pattern correctly (calcom_add/update/delete/list_appointment), which is good. (2) Descriptions are present and moderately detailed (ranging 80-200 chars), above the hard floor but not optimized for LLM disambiguation. (3) All parameters have type definitions and descriptions, meeting the baseline requirement. (4) However, output schemas are NOT documented, neither in tool descriptions nor in parameter definitions. The LLM cannot infer what fields calcom_list_appointments returns or what structure calcom_add_appointment yields. (5) Error handling is minimal, no recovery guidance, no actionable error messages, no categorization of retryable vs fatal errors. (6) No idempotency or confirmation pattern for destructive operations (delete). (7) The code shows rate limiting logic but no per-parameter constraints (e.g., eventTypeId must be >0, date formats must be YYYY-MM-DD). Overall, the definitions are functionally complete but lack production-grade error guidance and output documentation.

• Add explicit output schema documentation to each tool description. Example: 'Returns: {id: number, eventTypeId: number, startTime: string, endTime: string, attendees: [{name: string, email: string}], status: string}'
• Implement actionable error messages in the catch blocks. Instead of generic errors, return 'Invalid start time: must be ISO 8601 format (YYYY-MM-DDTHH:mm:ss.sssZ). Got: ' + startTime. Reference the pattern at https://arcade.dev/patterns/recovery-guide
• Add a confirmation step for calcom_delete_appointment. Introduce a 'confirm' boolean parameter (default false) that requires explicit confirmation before deletion. Document this as a safety measure.
• Add JSON Schema constraints for date/time parameters: startTime and endTime should include 'format: date-time'; startDate and endDate should include 'pattern: ^\d{4}-\d{2}-\d{2}$' and minLength/maxLength. Add examples in parameter descriptions.
• Enhance tool descriptions with dependencies and prerequisites: 'To update an appointment, you must first list appointments (calcom_list_appointments) to find the bookingId if not already known.'
• Document pagination behavior for calcom_list_appointments if the Cal.com API supports it. If results can be large, add limit and offset parameters and document the maximum result count returned.
• Add parameter constraints to the schema: eventTypeId should have minimum: 1; notes could add maxLength: 500. These prevent the LLM from passing nonsensical values.
• Categorize errors in recovery guidance: 'If you receive a 404 error, the appointment may have been deleted. Retry is not recommended. Check with list_appointments.' vs 'If you receive a 429 (rate limit), wait and retry.'