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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. With no output schema, the description earns credit for disclosing return behavior: the two response shapes, the eight-product cap, and the special case where carriers return their mounting points and base racks. It omits pagination/rate-limit details, keeping it out of the top band.

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 core fact (what fits one vehicle) is front-loaded in four words, and the two mode branches follow in order. The second sentence is dense and comma-heavy but every clause carries distinct payload information rather than 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 five-parameter, no-output-schema read tool, the description covers both request modes and the shape of what comes back, which is what an agent needs to call it correctly. It leaves the relationship to check_fit and the source of vehicle handles (beyond the schema's find_vehicle hint) unstated, a minor but real gap.

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 explains make/model/year/category/roof_type with examples. The description reinforces how category changes behavior but adds no syntax or format detail for year, model, or roof_type beyond what the schema provides, which is the expected baseline.

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 names a specific verb+resource (what fits one vehicle) and enumerates the return payload for both modes, so the agent knows exactly what this tool produces. It does not, however, distinguish itself from the closely related check_fit sibling, so the purpose is clear but not fully routable without opening the other tool's 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?

It implicitly tells the agent when to include a category: omitting it yields per-category counts and handles, supplying it yields up to eight concrete products with fits and prices. That is useful branch guidance, but there is no explicit when-to-use-this-vs-check_fit-or-search_products statement and no stated prerequisites beyond the schema's hint that find_vehicle supplies handles.

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