mcp-io has 3 tools with inconsistent quality. Two tools (geocode_city, get_weather) have detailed schemas and good descriptions with proper type information. However, the 'greet' tool has a trivial description ('say hi') that violates the 20-character minimum guidance and provides minimal LLM decision-making context. Input schemas are present and properly typed for all tools, but descriptions vary widely in usefulness. No error handling guidance is visible in the tool definitions. No pagination support for any list-returning operations. Parameter descriptions are present but sparse in some cases. The tool set lacks composition patterns, no tools reference output from other tools in their parameters, which limits chaining capability.

• Rewrite 'greet' description from 'say hi' to something substantive like 'Greet a person by name to establish friendly rapport before making requests. Returns a personalized greeting message.' (90+ chars, context for LLM decision)
• Add parameter constraints to city_name: 'US city name (e.g., New York, Boston). For ambiguous names (e.g., Springfield), use state abbreviation suffix (Springfield, MA).' This guides LLM input and prevents invalid lookups.
• Document error recovery in geocode_city: 'If city is not found, returns error with list of similar cities. LLM should suggest closest match or ask user for clarification.' This enables self-correction.
• Add explicit output field documentation: 'get_weather returns {latitude: number, longitude: number, forecast: array, valid_until: ISO8601}. Latitude and longitude match input; use these to identify location in responses.' This ensures chaining compatibility.
• Add idempotent annotations to geocode_city and get_weather in tool registration (toolAnnotations), both are read-only and can be safely retried.
• Consider adding batch variant: 'geocode_cities(city_names: [string]) -> [{name, latitude, longitude}]' to avoid N sequential calls if LLM needs multiple city coordinates.

Inferred effective spec: 2026-07-28+.

• Relies on Roots (deprecated) - pass files/dirs via tool parameters, resource URIs, or configuration