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

Annotations already declare readOnlyHint=true and openWorldHint=false, and "Read-only, nothing is stored" largely restates that. The genuinely additive disclosures are the failure semantics ("A changed verdict or receipt fails") and the free/no-cost nature, plus the HTTP endpoint equivalence — useful, but thin beyond what the annotations already imply.

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?

Front-loads "Free" and the core action, then the mechanics of what to pass and what comes back, with no filler. The parenthetical tool list is long but earns its place by telling the agent which answers are verifiable.

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?

Covers cost, safety profile, input requirement, return fields, failure condition, and the REST equivalent, which is substantial for a three-parameter tool with an output schema. The main gap is the lack of any routing cue against check_payment_proof, leaving ambiguity in a crowded verification-tool family.

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 schema already documents all three parameters; the description only adds that route and input together enable the exact-request check, which is a modest but real gain over the schema. Baseline 3 applies since the schema does the heavy lifting.

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 ("check the signed receipt that every paid x402 Doctor answer carries") and enumerates which answer types carry receipts (diagnose, preflight, batch, deep, fix, delivery check; HTTP or MCP). That scope is very clear, but it never distinguishes itself from the verification-oriented sibling check_payment_proof, so an agent still has to infer which verifier applies.

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 concrete motivating scenario ("to prove later which verdict you got before paying an endpoint") and states the calling convention ("Pass the whole answer as response"). It stops short of explicit when-not guidance or naming an alternative verifier for the cases this one does not cover.

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