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

Annotations already cover read-only, idempotent and closed-world safety, but the description adds non-obvious behavior: terms filters are exclusive and non-publishing companies are surfaced in excluded_terms_not_published, and the guidance to tell the user to ask them. It also discloses the failure mode (unknown place/make/tag returns empty with did_you_mean). It stops short of covering pagination/limit behavior, though the cursor param is documented in schema.

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?

Purpose is front-loaded, then usage scenarios, then edge behavior and the sibling handoff. Sentences are dense and one clause chain ('verified ownership and published rental terms: minimum renter age, delivery, unlimited mileage and deposit') runs long, but nothing is wasted.

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 13-param, zero-required filter tool with a full schema and an output schema, this is complete: it covers purpose, selection scenarios, filter semantics, the empty-result path (did_you_mean), the excluded-companies reporting, and the sibling for single-company lookups. Return shape can be left to the output schema.

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 coverage is 100%, so baseline is 3, but the description adds real semantics beyond per-param text: it explains that terms filters are publish-or-exclude and that omitted companies are reported separately, and clarifies sort=rank as the site's own order. It doesn't add format details for the place/make strings, which the schema already handles.

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 specific verb and resource ('Find independent exotic car rental companies') plus the dimensions searchable (state/city, make, specialization, rating, verified ownership, terms). It also explicitly distinguishes itself from the sibling get_company, so an agent can route without reading either schema.

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?

Gives concrete when-to-use triggers with real user phrasings ('I'm 23, who rents to me in Las Vegas with delivery?'), names the three query shapes it serves, and points to get_company for the single-company case. No alternatives are left to inference.

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