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 data source ('Radio Browser (Public Domain)'), update frequency ('updates daily'), and detailed return format ('Returns the Katzilla envelope { data, quality, citation }' with explanation of quality scores and citation components). Annotations already cover read-only, non-destructive, idempotent, and open-world characteristics, so the description appropriately supplements with operational details.

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 three sentences: purpose and filtering, return details, and source/format information. Every sentence adds value without redundancy. It's appropriately sized for the tool's complexity and front-loads the core functionality.

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 has comprehensive annotations (readOnlyHint, destructiveHint, idempotentHint, openWorldHint), 100% schema coverage, and an output schema (implied by the detailed return format description), the description provides excellent contextual completeness. It covers purpose, usage context, behavioral details, source attribution, and return format - everything needed for effective tool selection and invocation.

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, the input schema already fully documents all three parameters (name, limit, country). The description mentions filtering by 'name and country' which aligns with the schema but doesn't add significant semantic value beyond what's already in the structured fields. The baseline of 3 is appropriate when the schema does the heavy lifting.

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: 'Search internet radio stations worldwide' with specific filtering capabilities ('Filter by name and country') and details what it returns ('station name, URL, codec, bitrate, and tags'). It distinguishes itself from sibling tools by focusing on radio station search, unlike other fun tools like chess, trivia, or gaming APIs.

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 ('Search internet radio stations worldwide') and implies usage for media/reference purposes. However, it doesn't explicitly state when NOT to use it or name specific alternatives among the sibling tools, though the context suggests it's for radio station data specifically.

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