carsdotcom_vehicle

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

With no annotations, the description carries the full burden of behavioral disclosure. It clearly states that the tool uses 'credential-free public data sourced directly from Cars.com's own public GraphQL API,' which informs the agent that no authentication is needed and the data is public. It also notes conditional fields like private-seller detail and CPO detail 'when applicable,' showing awareness of variable response shapes. It doesn't mention rate limits or error behavior, but for a read-only detail fetch this is a strong disclosure.

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 a single, dense sentence that packs in a comprehensive list of return fields without filler. It front-loads the core purpose and then details contents. While it's long, the tool itself returns a rich payload, so the length is justified. It could be improved by breaking the list into bullet points, but it is not wasteful.

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 that there is no output schema and no annotations, the description compensates by thoroughly enumerating the expected return data: vehicle specs, pricing, equipment, history, seller notes, dealer info, and program details. It also covers data source and authentication context. The only missing elements are potential error cases and how to obtain the listing_id, but for a single-parameter detail tool this is largely complete.

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?

The schema already provides 100% coverage for the single parameter listing_id, including its UUID format and URL path context. The description adds no additional parameter semantics beyond the tool name itself. Per the baseline rule, a score 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 leads with a specific verb-resource pair ('Get Cars.com vehicle listing detail') and then exhaustively enumerates the returned data fields (spec, pricing, history, dealer info, etc.), making the tool's purpose unmistakable. It also implicitly distinguishes itself from sibling tools like carsdotcom_search by focusing on detail retrieval for a single listing.

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 no explicit guidance on when to use this tool versus alternatives, nor does it mention that listing_id would typically come from a search tool like carsdotcom_search. It states the data is 'credential-free public data' which gives some context, but it never says 'use this when you have a listing_id' or excludes use cases.

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