get_pricing

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 discloses that the call is free and requires no wallet or API key, which is important behavioral context. It also identifies the HTTP GET method. However, it does not mention rate limits, response size, or whether the response is paginated, which would add further transparency.

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 earning its place: the first defines the resource and contents, the second gives the usage scenario, and the third states the auth/access requirements. It is front-loaded with the action and resource, and contains no filler or redundancy.

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 discovery tool with no parameters and no output schema, the description is remarkably complete. It covers the exact data returned (endpoints, parameters, prices, network, sources, attribution), the intent (discover what you can buy), and the authentication requirements (none). This fully equips an agent to invoke it 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 input schema has zero parameters, so there are no parameter details to explain. The description compensates by clearly describing what the tool returns. Baseline for a no-parameter tool is 4, and the description exceeds that by detailing the output contents.

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 uses the specific verb 'Get' and clearly identifies the resource as the Vindex endpoint catalog with per-call USD prices. It explicitly names the endpoint path (GET /discovery) and lists the contents (paid endpoints, params, prices, network, sources, attribution), which distinguishes it from siblings like get_health or decode_vin.

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 provides a clear use case: 'Use this to discover what you can buy and what it costs.' This tells the agent when to invoke the tool. It does not explicitly compare to alternatives like get_purchase_costs, but the context of discovery/pricing is distinct enough that no exclusion is necessary. The lack of explicit alternative naming prevents a 5.

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