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

Annotations already establish read-only, idempotent, open-world, and non-destructive behavior. The description adds useful beyond-annotation context: data is retained ('retained'), may be absent ('when available'), and is not a complete ownership/accident history. No contradiction with annotations.

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 purposeful sentences with the core action and caveat front-loaded. No filler or repetition of schema details.

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 simple, one-parameter read-only lookup with rich annotations, the description covers data source, availability caveat, and limitations. The lack of output schema is acceptable because the history concept and scope are clear enough to invoke correctly.

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 fully documents the sole identifier parameter (VIN or slug_vin), so the description doesn't need to compensate. It adds marginal framing ('one supported vehicle') but no new parameter-level semantics.

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 a concrete verb and resource ('Retrieve retained Copart + IAAI auction history') and scopes it to one supported vehicle, which separates it from sibling tools for vehicle details, related vehicles, and search. The negative clause also distinguishes it from ownership/accident-history lookups.

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 clearly signals when this tool applies: for a single supported vehicle's auction history, when available, and explicitly warns that it is not a complete ownership/accident record. It does not name alternative sibling tools explicitly, but the scope plus caveat gives enough selection context.

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