Katzilla MCP

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

Annotations already provide readOnlyHint=true, destructiveHint=false, idempotentHint=true, and openWorldHint=true, covering safety and idempotency. The description adds valuable context beyond this: it discloses the source (APIs.guru), update frequency (monthly), and details about the return structure (Katzilla envelope with quality scores and citation info), which helps the agent understand data freshness and auditability.

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 efficiently structured in two sentences: the first states the purpose and source, the second details the return format. Every sentence adds value without redundancy, making it front-loaded and appropriately sized for a zero-parameter tool.

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 complexity (simple read operation with no parameters), rich annotations (covering safety and idempotency), and the presence of an output schema, the description is complete. It adds necessary context about the source, update frequency, and return structure, ensuring the agent understands the data's nature and limitations.

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 0 parameters with 100% coverage, so no parameter documentation is needed. The description appropriately does not discuss parameters, focusing instead on output semantics. It adds meaning by explaining the return format ('Katzilla envelope') and its components, which compensates for the lack of input parameters.

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 ('Get a summary of all public APIs tracked by APIs.guru') and resource ('public APIs'), distinguishing it from siblings by focusing on API metadata rather than specific data domains like agriculture, crime, or economics. It explicitly mentions the source and update frequency, which adds specificity.

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 implies usage for retrieving API summaries from APIs.guru, but does not explicitly state when to use this tool versus alternatives among the many sibling tools. It mentions the source and data characteristics, providing some context, but lacks direct guidance on alternatives or exclusions.

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