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

Annotations already indicate read-only, idempotent, non-destructive behavior, and the description adds substantial context beyond them: the tool is free, the analysis costs 0.10 USDC settled only after completion, and it records a baseline snapshot on first check. No contradiction with annotations exists.

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 longer than average and spends many words on the paid analysis, but every sentence earns its place by clarifying cost, flow, or the tool's limited role. It is well-organized and front-loaded with the primary purpose, though the direct tool behavior is somewhat buried mid-description.

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 (two-step flow, payment protocol, snapshot baseline) and the presence of an output schema, the description provides all essential context: free validation step, paid analysis details, cost settlement, and how to proceed. Nothing critical for correct invocation 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% for the sole parameter, so the baseline is 3. The description aligns with the schema's 'JSON or YAML' and public-URL constraints but does not meaningfully add parameter-specific semantics beyond what the schema already documents.

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 names the resource ('public OpenAPI/Swagger spec') and the specific verb 'audit', then sharply distinguishes what the MCP tool itself does (validate URL, return x402 endpoint) from the separate paid analysis. Even without siblings to differentiate from, the purpose is explicit 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?

It explicitly states what the tool does NOT do ('does not run the analysis or move funds') and gives a precise follow-up instruction: POST {'url': ...} to the returned endpoint with an x402-capable client. The description fully explains the two-step flow and cost conditions, leaving no inference needed.

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