decode_vin

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

With no annotations, the description carries full disclosure burden: it does name what data comes back (model, MVS version, build date, engine number, colours, CARATT options), which is genuinely useful. It says nothing about failure behavior for unknown/invalid VINs, whether results hit an external ePER service (latency, rate limits), or read-only/reversibility traits.

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?

A single front-loaded sentence with the action and scope first and the return fields following. No filler, nothing repeated from structured fields.

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 and no annotations, the list of returned fields is a meaningful compensation, but the definition still leaves an agent without error handling guidance, any indication of external-service dependency, or whether partial results are possible (e.g., VIN unknown in some catalogues).

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% and each parameter (vin, lang, include_options) is documented in the schema, so baseline 3 applies. The mention of 'factory options (CARATT)' loosely maps to include_options but adds no syntax or defaulting detail beyond the schema.

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 (Decode) plus resource (VIN) and names the data source (ePER chassis data), then enumerates the payload. No sibling in the list does VIN decoding, so no differentiation is needed, though the enumeration reads more like a field list than a purpose statement.

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?

There is no when-to-use / when-not-to-use guidance, no prerequisite conditions (e.g., that a 17-char VIN is required, or that it queries ePER chassis data specifically), and no pointer to any alternative tool for parts lookup if the VIN is not found. Usage is only implied by the verb.

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