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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the bar is lower. The description still adds genuinely non-obvious behavioral context: unknown URLs are simply not crawled, meaning no side-effects or network fetching result from passing arbitrary input. It does not describe the response shape or what a match/non-match looks like.

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?

Two short sentences, front-loaded with purpose and followed by the one behavioral caveat that matters. No filler or repetition.

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 5 parameters, multiple enums, and deeply nested constraint/profile objects and no output schema, two sentences are far too thin. An agent has no guidance on how `mode`, `view`, or `constraints` alter results, or what the return value contains when a URL is matched or 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 0% across 5 parameters, including two large nested objects (constraints with ~17 sub-properties and a deeply nested caller_profile). The description only implicitly maps to `urls` and says nothing about `mode`, `view`, `constraints`, or `caller_profile`, leaving the agent to reverse-engineer the schema.

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?

States a concrete verb+resource: check whether given service URLs are in the catalogue. The phrase 'URLs you found elsewhere' implicitly separates it from discovery-oriented siblings like search_sites and browse_catalogue, but it never names an alternative explicitly.

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?

'URLs you found elsewhere' implies the usage situation (you already have candidate URLs and want to validate them), and the note about unknown URLs hints this is a validation step rather than discovery. However, there is no explicit statement of when to prefer this over search_sites/browse_catalogue/inspect_site, nor what to do with URLs that come back unknown.

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