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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so safety is covered. The description adds real payload context — the full field set returned and the fact that equipment, tire and child-seat campaigns are included as well as vehicles — which the annotations do not convey. It stops short of noting behavior for unknown campaign numbers (empty vs. error) or how limit truncation manifests in the response.

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?

Two tight sentences: the identity and scope first, the returned fields second, with no filler. Dense enumeration of fields is efficient, though the long list is slightly heavy for a two-sentence description and some examples restate schema content.

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 takes on the job of describing return content, and it does so concretely. Combined with fully documented parameters and a complete annotation set, an agent has enough to invoke it correctly; only error/empty-result behavior is left unstated, which is a minor gap for a single-record lookup.

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 campaign_number, limit and detail are already documented, and the description's format examples (20V314000, 20V-314, 23C001) largely duplicate the schema's own examples. Neither limit nor detail is illuminated beyond the schema, so this sits at the 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?

States a specific verb and resource ("Returns one NHTSA recall campaign by its campaign number") and enumerates exactly what comes back — manufacturer, report date, component, summary, consequence, remedy, unit counts, advisories, makes/models/years. The single-record-by-ID scope also implicitly separates it from the sibling list/search tools (vehicle_recalls, consumer_product_recalls), and it declares coverage of V/E/T/C campaign types.

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?

Usage is only implied: the reader infers "call this when you already have a campaign number." There is no explicit when-not guidance and no named alternative such as vehicle_recalls for searching without an ID, so an agent must reason about routing on its own.

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