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

No annotations are provided, so the description carries the full burden. It discloses that the tool searches across multiple sources and returns listings with specific fields. However, it does not mention any limitations, rate limits, authentication requirements, or what happens if no results are found. It does not contradict anything, but it lacks depth in behavioral disclosure beyond the basic function.

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, concise sentence that front-loads the primary action and result. Every part is informative with no waste. It efficiently communicates the tool's purpose without unnecessary elaboration.

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?

Despite 12 parameters and no output schema, the description provides enough context by mentioning the return fields (prices, mileage, deal ratings, links). It does not explain ordering, pagination, or error handling, but the schema covers parameter semantics. Given the tool's complexity, it is reasonably complete, though slightly more detail on result behavior would justify a 5.

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 provides 100% coverage with descriptions for every parameter. The tool description does not add additional parameter-specific semantics beyond what the schema already states, such as the use of 'maxResults' or 'oneOwner'. Per the baseline rule, since schema coverage is high, a score of 3 is appropriate.

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 states a specific verb ('Search'), a specific resource ('car deals'), and names the sources (Cars.com, Autotrader, KBB) and return types (prices, mileage, deal ratings, links). It is clear and distinct, though there are no sibling tools to differentiate from. The purpose is unambiguous.

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 clearly implies usage: search for car deals using the provided filters. Since no sibling tools are listed, there is no need to specify alternatives or exclusions. The context is clear, but it does not explicitly state when not to use or what alternatives exist. Given the absence of siblings, this is adequate.

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