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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld behavior. The description adds that the tool is 'Free' and returns 'the score, each rule's result with how to fix it, and the most costly findings'—useful cost and output context beyond the annotations. It does not mention rate limits or auth requirements, so a 4 rather than 5.

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?

Front-loads the core purpose, then efficiently covers input, output, cost, and usage in four tight sentences. Every sentence carries distinct information, with no redundancy or filler.

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?

For a tool with no output schema and full annotation coverage, the description supplies all needed context: what it does, how to supply input, what it returns, that it is free, and when to use it. Nothing material is missing.

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%, so the schema already documents both parameters thoroughly, including mutual exclusivity ('Send url or spec, not both'). The description's 'Give the spec's https URL or the spec itself' adds only slight emphasis and no syntax or format details beyond the schema, fitting the baseline 3.

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?

Specific verb 'Scores' with resource 'API' and precise scope: '0-100 for how well AI agents will use it as tools, from its OpenAPI 3.0 or 3.1 spec.' Lists the evaluated criteria and the source of rules, making the tool's function unmistakable even among unrelated siblings.

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?

Explicitly states when to use it: 'Use it before turning an API into an MCP server or listing it for agents.' Also tells the agent how to provide input ('Give the spec's https URL or the spec itself'). No when-not-to-use or alternative tools are mentioned, so it falls short of a 5.

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