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 annotations: it discloses the data source (Ziptastic Free API), update frequency (daily), and detailed return structure (Katzilla envelope with quality scores and citation details including SHA-256 hash). This enriches the agent's understanding of 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 core functionality and source, and the second details the return format and its components. Every sentence adds critical information (e.g., data source, update frequency, return envelope structure) without redundancy, making it front-loaded and 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 (single parameter, read-only), rich annotations (covering safety and idempotency), and the presence of an output schema (implied by 'Returns the Katzilla envelope'), the description is complete. It adds necessary context like data source, update frequency, and return structure details, which complements the structured fields effectively without needing to explain basic operations or output values.

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 a single parameter 'zipcode' documented as 'US zipcode'. The description adds no additional parameter semantics beyond what the schema provides, such as format examples (e.g., 5-digit) or validation rules. With high schema coverage, the baseline score of 3 is appropriate, as the description does not compensate but also doesn't need to given the schema's completeness.

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 tool's purpose with a specific verb ('Get') and resource ('city, state, and country for a US zipcode'), and distinguishes it from siblings by specifying its geographic focus and data source (Ziptastic). It explicitly mentions the return format, which helps differentiate it from other geo tools like geo__census-geocoder or geo__geocode-xyz.

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 ('Get city, state, and country for a US zipcode') and implies limitations (US-only, daily updates). However, it does not explicitly state when not to use it or name specific alternatives among the many sibling tools, such as geo__census-geocoder for broader geocoding or geo__postal-pincode for non-US postal codes.

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