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

The description adds genuinely non-structured information: the call costs $0.05 USDC on Base, and it consumes an anti-replay nonce, which explains the non-idempotent and non-readOnly annotations. It does not say what happens on a failed verification or whether the nonce is burned on failure, which is material for a paid, non-idempotent call.

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?

Two dense sentences with no filler; the purpose and the enforcement scope are front-loaded before the cost note, which is exactly the ordering an agent needs.

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 verification tool with no output schema, the description never indicates what a result looks like (pass/fail verdict, reason codes, whether a signed receipt is returned). Combined with 43% schema coverage and a nested six-required-parameter payload, an agent can decide when to call it but not how to interpret the response.

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 only 43%, so the description must compensate – and it does by mapping the enumerated checks onto parameter groups (authorization→mandate, payment.amount→amount, payment.recipient/destination, merchant, expires_at→expiry, nonce→replay risk). It still leaves nested optional fields such as human_confirmed and allowed_domains without meaning.

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 a specific verb ('checks') and resource ('payment intent' preflight), and enumerates the exact facets verified (mandate, amount, destination, merchant, expiry, replay risk). Differentiation from siblings is only implicit – 'before an autonomous payment executes' distinguishes it from verify_agent_action_intent, but the sibling is never named.

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?

'Paid transaction preflight ... before an autonomous payment executes' gives a clear triggering context and sequencing constraint. It stops short of naming alternatives (e.g., when to use verify_agent_action_intent instead) or stating exclusions, so it does not reach a 5.

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