Global VIN Decode (Auto.dev)

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

Annotations already declare readOnlyHint, destructiveHint, idempotentHint, and openWorldHint. The description adds the behavioral detail that data is cached for 24 hours, which is beyond annotations. It does not contradict any 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?

The description is two sentences long, front-loaded with the core purpose and key differentiator, with no redundant or filler content. Every word serves a purpose.

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?

Given the tool's complexity (global VIN decoding) and the presence of an output schema, the description covers the input scope, caching behavior, and the types of data returned. It lacks mention of error handling or rate limits, but annotations cover idempotency.

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 coverage is 100%, so the schema already describes the vin parameter with length and examples. The description does not add new parameter semantics beyond what the schema provides, so a baseline 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 clearly states it decodes VINs worldwide (100+ countries) and lists specific attributes (make, model, year, etc.), distinguishing itself from US-only NHTSA decoders. The verb 'decode' and resource 'VIN' are specific and 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 explicitly notes coverage of EU, Asia, and other markets beyond US-only NHTSA, providing clear guidance on when to use this tool (global VINs) versus the sibling vehicle.vin.decode (US-only). It also mentions a 24-hour cache, which is a usage consideration.

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