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

Beyond the annotations (readOnly, openWorld=false, non-destructive), the description discloses the exact checks performed (ID vs registrations, wallet consistency, HTTPS/public hosts, EIP-55, CAIP-10), the side-effect boundary (no fetch, no chain lookup, no counterparty contact, no payment moved), the x402 price and free-call allowance, and the required X-Wever-Wallet-Proof binding. This is unusually rich behavioral context that an agent cannot get from the structured fields alone.

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?

Content is front-loaded: purpose first, then what the report checks, then side-effect boundaries, then payment and auth mechanics. It is dense but every clause carries operational information; the contract and human-page URLs are the least essential elements for an agent.

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, the description carries the burden of describing the return value and does so ('signed report marks each identity element present or missing', 'Ed25519 signed receipt'). Payment terms, authentication header, and a contract reference are all present, leaving nothing material an agent needs before calling.

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 by enumerating acceptable record shapes (ERC-8004 registration file, passport excerpt) and the fields they may carry, plus the formats the checker validates against. The optional 'label' parameter is not mentioned in the description, keeping it from a 5.

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 opens with a specific verb and resource ('check an agent identity record') and states the timing intent ('before you deal with the agent'), which separates it from generic trust or delegation tools. It never names a sibling tool, so the differentiation is implied by scope rather than made explicit.

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?

'Check ... before you deal with the agent' gives a clear triggering condition, and the 'reads only the material in the call: no page fetch, no registry or chain lookup' clause implicitly tells the agent this is not a live-verification tool. No explicit alternative or when-not guidance is offered, so it falls short of a 5.

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