The WHOOP MCP server demonstrates above-average definition quality for a health/wearables domain with 30 tools. Strengths: comprehensive tool coverage, clear action-verb naming (whoop_get_*, whoop_list_*), structured parameter schemas with enums for privacy_mode and response_format across all tools, and consistent descriptions explaining what each tool does and when to use it. Weaknesses: many descriptions are at the lower end of the optimal range (10-20 chars shy of 50-200 char baseline); parameter descriptions are minimal in places (e.g., 'Cycle ID' is brief); no explicit output schemas documented; error handling and recovery guidance missing from descriptions; some tools conflate multiple responsibilities (e.g., whoop_get_profile reads from API while whoop_profile_get reads from local storage, risking LLM confusion); no per-tool security/permission documentation. Tool definitions are directly visible in source (scripts/smoke-tools.mjs), so no inference penalty applied. Average description length across all tools: ~140 chars, acceptable but below A-tier baseline of 194 chars. Schema presence is strong (all tools have typed, described parameters with enums), but output schemas are not explicitly documented in the tool metadata.

• Document output schemas for all data retrieval tools. Include response object structure, field names, and types. Example: whoop_get_profile returns {user_id: string, email: string, first_name: string, recovery_score: number, strain_level: 0-21, ...}.
• Rename whoop_profile_get to whoop_get_profile_local (or add a 'source' enum parameter to whoop_get_profile) to eliminate naming confusion with whoop_get_profile.
• Add error recovery guidance to tool descriptions. Example for whoop_exchange_code: 'If code is invalid or expired, call whoop_get_auth_url to restart the OAuth flow. Invalid codes cannot be retried, a fresh auth flow is required.'
• Expand date/time parameter descriptions to specify timezone (UTC assumed), format strictly (ISO 8601 or YYYY-MM-DD), and behavior on boundary conditions.
• Add pagination documentation to list_* tools: 'By default, returns first 10 results (max_pages=10). Pass all_pages=true to fetch complete result set. Includes total_count in response.'
• Declare permission/scope requirements in descriptions for sensitive tools (exchange_code, revoke_access, profile_update). Example: 'Requires: oauth:write scope. Warning: revoke_access is irreversible and will disconnect the agent from WHOOP.'
• Expand parameter descriptions for IDs. Instead of 'Cycle ID', write 'The WHOOP cycle UUID (returned by whoop_list_cycles). Example: 550e8400-e29b-41d4-a716-446655440000'.
• Document the behavior and return value of whoop_demo, including whether it returns live-like data or obviously synthetic examples, and when agents should switch from demo to live API calls.