Katzilla MCP

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering safety and idempotency. The description adds valuable context beyond annotations: it specifies the source ('geocode.xyz'), update frequency ('updates daily'), and details about the return structure ('Katzilla envelope') including quality metrics and citation info. No contradiction with annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is front-loaded with the core purpose, followed by source details and return format. Every sentence adds value: the first states the action, the second specifies source and update frequency, and the third explains the output structure. It is appropriately sized with zero waste.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the tool's low complexity (1 parameter), rich annotations (covering safety and idempotency), and the presence of an output schema (implied by 'Has output schema: true'), the description is complete. It adds necessary context like source, update frequency, and output details, compensating well where structured data might lack.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, with the parameter 'query' fully documented in the schema as 'Location to geocode'. The description does not add any additional meaning or syntax details beyond what the schema provides, such as examples or formatting requirements, so it meets the baseline of 3.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the specific action ('Geocode a location query to get coordinates'), the resource ('using geocode.xyz'), and distinguishes it from siblings by specifying the source and data format ('Katzilla envelope'). It avoids tautology and provides distinct purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides clear context for when to use this tool ('Geocode a location query to get coordinates'), mentions the source ('geocode.xyz (Free Tier)'), and implies usage for coordinate retrieval. However, it does not explicitly state when not to use it or name alternatives among siblings (e.g., geo__census-geocoder, geo__nominatim), which prevents a score of 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.