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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the safety profile is covered. The description adds useful behavioral context beyond annotations: it enumerates exactly what the response includes (NHTSA summary, model years, documents with verified PDF links, page URL) and discloses that the answer explicitly says it is not a recall.

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 efficiently structured: it opens with the resource and lookup method, provides illustrative examples, lists return contents, then closes with the recall caveat. Every sentence adds information; there is no fluff or repetition of the schema.

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?

With no output schema, the description fully carries the burden of explaining return values, and it does so explicitly: summary, model years, documents, PDF links, and page URL. It also covers the optional 'make' behavior and warns about the recall distinction. Nothing an agent needs to invoke it correctly is 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 100%, so the baseline is 3. The description adds value beyond the schema by giving concrete number formats and examples, and by explaining the subtle behavior of the 'make' parameter: 'A number filed under several makes returns each without it.' This extra guidance helps agents use the parameters correctly.

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 lookup action with a clear resource: manufacturer service bulletins, campaigns, warranty extensions, or OTA notices found by their number. It gives concrete examples (Hyundai 9D6, Kia SC199) and explicitly distinguishes itself from recalls, which differentiates it from sibling tools like check_recalls.

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 when to use the tool: when you have a bulletin, campaign, or document number from a letter or document. It also provides a when-not warning ('These are NOT safety recalls'), but it does not explicitly name alternative tools or direct the agent to check_recalls for recall lookups.

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