Single tool (list_doctors) with basic structure but significant gaps in definition quality. The tool has a reasonable name starting with a verb (list_), an adequate description (168 characters, within baseline range), and parameters with type definitions and descriptions. However, the schema lacks critical production-grade features: no output schema documentation, no pagination support despite returning lists, no error handling guidance, and parameters are marked as optional (not required) without rationale. The tool is READ_ONLY (safe), but the server lacks any mechanism for handling invalid input beyond a simple error dict return. The description includes example output in the docstring ('Example: [...]'), which violates the pattern guidance to avoid example values that LLMs may reuse literally. Input validation is minimal (checks for at least one param) but doesn't validate format of state codes or city names. The tool definition is directly visible in code (examples/mcpserver.py), so no inference penalty applies, but the overall quality is below production baseline (median 45-55 for typical servers; this lands at lower end due to missing output schema, pagination, and error guidance).

• Add explicit output schema: Document that list_doctors returns [{name: str, specialty: str, address: {state: str, city: str, street: str, zip: str}, ...}]. Include this in tool docstring or as structured TypedDict.
• Implement pagination. Add optional parameters: limit (default 20, max 100) and offset (default 0). Return {doctors: [...], total: int, offset: int, limit: int, hasMore: bool}.
• Mark state and city parameters as optional, but describe the interaction clearly: 'At least one of state or city is required. If both provided, results matching both criteria are returned. Case-insensitive.'
• Remove example output from docstring. Instead, document return structure in schema or as a separate note: 'Returns list of doctor objects with fields: name (str), specialty (str), address (object with state, city, street, zip), phone (str)'.
• Improve error handling. Return structured error: {error: {code: 'MISSING_CRITERIA', message: 'Provide state and/or city', retryable: false}, doctors: []}. Add recovery guidance in description: 'If unsure of state code, try a city name or call with broad filters.'
• Validate state codes. Accept only valid 2-letter state/territory codes (AL, AK, ..., WY, DC, PR, etc.). Return actionable error: 'Invalid state code: ZZ. Valid codes: AL, AK, AZ, ...' with a few suggestions.
• Add limit enforcement. Cap results at 100 by default. If more than limit match, return hasMore: true and instruct LLM: 'More doctors available. Refine search (e.g., add city) or paginate with offset parameter.'