Katzilla MCP

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

The description adds valuable behavioral context beyond annotations: it discloses the return format ('Katzilla envelope { data, quality, citation }'), explains what quality scores measure ('freshness/uptime/confidence'), and describes citation components ('source URL, license, and a SHA-256 data hash'). This complements the annotations which already indicate read-only, non-destructive, idempotent, and open-world characteristics.

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 purpose and source, the second explains the return format and its components. Every element serves a clear purpose 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 simple single parameter, comprehensive annotations, and existence of an output schema, the description provides complete context. It explains what the tool does, its data source, update frequency, and return format structure, making it fully adequate for agent understanding.

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?

With 100% schema description coverage and only one parameter with a clear enum and default value, the schema already fully documents the parameter. The description doesn't add any additional parameter semantics beyond what's in the schema, so the baseline score of 3 is appropriate.

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 exchange rates'), resource ('from the National Bank of Poland'), and scope ('Source: NBP (Public Data), updates monthly'). It distinguishes itself from siblings like 'economic__exchange-rates' by specifying the Polish national bank source and monthly update cadence.

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 about when to use this tool ('Get exchange rates from the National Bank of Poland') and mentions the data source and update frequency. However, it doesn't explicitly state when NOT to use it or name specific alternative tools for different exchange rate sources.

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