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

Goes well beyond the annotations by disclosing the x402 v2 payment protocol (exact USDC on Base), that the first call is free, that settlement happens once per signature and replays return 409, that the report is only returned after settlement, and the meaning of 503/402/502 errors. This is exactly the behavioral context an agent needs for a paid mutation.

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?

Dense and front-loaded: report contents first, then payment flow, then settlement and error behavior. Every sentence carries operational information and there is no filler.

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 two-parameter paid tool with no output schema, the description covers what the report contains, how to obtain and use the payment signature, settlement semantics, replay behavior, and error codes. Nothing an agent needs in order to call it 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 coverage is 100%, so the baseline is 3, but the description adds real meaning: payment_signature must be the base64 PAYMENT-SIGNATURE corresponding to one of the accepts returned by the unpaid call. That flow semantics is not in the schema and materially improves correct invocation.

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 and resource: a signed proof report for an agent, enumerating its contents (Proof Score per category, record count, settled value, buyer diversity) and marking it paid. It does not explicitly differentiate itself from siblings such as proof_index or proof_verify_record, so it is clear but not sibling-differentiating.

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?

Gives a clear call sequence: call without payment_signature to receive payment requirements with no charge, then call again with the signature from one of those accepts. It does not say when to prefer this over proof_index, proof_verify_record, or agent_records, so context is clear but alternatives are unaddressed.

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