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 discloses the data source (GeoJS), update frequency ('updates daily'), and return structure ('Katzilla envelope { data, quality, citation }'), including details on quality metrics and citation contents. No contradictions with annotations exist.

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 in the first sentence, followed by supporting details in a structured manner. Every sentence adds value: source information, update frequency, return format, and quality/citation explanations. It is efficiently written with zero wasted words.

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 optional parameter), rich annotations (covering safety and idempotency), and the presence of an output schema, the description is complete. It explains the tool's purpose, source, update frequency, and return structure, compensating for any gaps. No additional details are needed for effective use.

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?

The input schema has 100% description coverage, with the 'ip' parameter fully documented in the schema ('IP address (omit for your own IP)'). The description does not add any parameter-specific semantics beyond what the schema provides, such as format examples or validation rules, so it meets the baseline of 3 for high schema coverage.

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 explicitly states the tool's purpose: 'Get geolocation data for an IP address using GeoJS.' It specifies the verb ('Get'), resource ('geolocation data'), and scope ('IP address'), and distinguishes itself from sibling tools (e.g., geo__ipinfo, geo__nominatim) by naming the specific API source (GeoJS).

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 usage: 'Get geolocation data for an IP address using GeoJS' and notes the source is a 'Free API' that 'updates daily.' It implies this tool is for IP-based geolocation, but does not explicitly state when to use it versus alternatives like geo__ipinfo or geo__nominatim, nor does it mention exclusions or prerequisites.

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