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

Annotations cover the safety profile (destructiveHint=false, idempotentHint=false, openWorldHint=true), and the description adds important behavior beyond that: the tool costs $0.001 USDC on Base per successful call via x402. It also notes that the tool returns retry guidance, which is useful operational context.

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 short, front-loaded sentences. It establishes the return value, usage context, and cost/payment mechanism with no wasted wording.

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 lookup with no output schema, the description is complete: it explains what is returned, when to use it, and the payment model. Nothing an agent needs in order to call the tool correctly is missing.

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 description coverage is 100%, so the schema already documents the single parameter. The description still adds value by specifying the valid range (1xx-5xx) and giving examples (402 Payment Required, 429 Too Many Requests) that help the agent populate the parameter correctly.

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 states exactly what the tool returns: the name, plain-language meaning, and retry guidance for an HTTP status code. It also scopes the input domain to 1xx-5xx and cites notable codes, so an agent can immediately distinguish it from unrelated lookup tools.

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 gives a clear context for use: handling API errors. It does not name alternatives or state when not to use it, but no sibling tool overlaps with this function, so the guidance is sufficient for routing.

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