decode_vin

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

No annotations are provided, so the description carries the full burden. It adds some behavioral context by mentioning the output details and the optional model_year optimization, but does not disclose potential limitations, error handling, or data freshness. This leaves room for improvement.

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 three sentences, each adding value: purpose, usage context, and parameter hint. No redundant information, perfectly concise.

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 presence of an output schema (implied), the description covers the tool's functionality and parameter semantics adequately. It distinguishes from siblings and includes a helpful note. Missing details about error handling or partial VIN handling, but overall sufficient for a straightforward tool.

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?

Input schema has 0% description coverage, so the description must compensate. It adds meaning by stating that vin is a VIN (17 characters or partial) and that model_year improves accuracy, but it could provide more explicit constraints or format guidance for both parameters.

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?

Description clearly states 'Decode a VIN into vehicle details (make, model, year, engine, plant, safety equipment)', specifying a verb and resource, and it distinguishes from sibling tools like check_vin_recalls and get_recalls which deal with different aspects.

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?

Description says 'Call this when the user provides a VIN... and wants to know what vehicle it is', giving clear when-to-use context. It also notes that passing model_year improves accuracy for pre-2001 VINs. However, it lacks explicit when-not-to-use guidance or alternatives.

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