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

Annotations already declare readOnlyHint and idempotentHint, so the safety profile is covered. The description adds a relevant recency constraint and enumerates returned fields, but it does not disclose behavior for missing or out-of-window campaigns or any response envelope details.

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?

One front-loaded sentence with no filler; every clause carries information. The long list of fields after the colon is dense, but still scannable, making this concise rather than verbose.

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 one-parameter read-only lookup with annotations and full schema coverage, the description covers the important output content. It is ambiguous about what happens for campaigns older than 12 months, and there is no output schema, but the returned-field list makes the tool usable.

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 single parameter is fully documented in the schema with a format pattern and example, so the description does not need to repeat it. It adds no further semantics beyond that 100% coverage.

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 the exact action ('Look up an NHTSA vehicle/equipment recall campaign') and enumerates the return fields, so an agent can tell this is a targeted, single-campaign lookup rather than a feed. It does not explicitly contrast with sibling latest_recalls, but the singular 'campaign' and the schema's required campaign ID make the resource clear.

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 gives clear context: use when you have a specific recall campaign and want its details, including a recency window of the last 12 months. It doesn't name alternatives or state when not to use it, so it falls just short of full guidance.

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