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

With no annotations provided, the description carries the disclosure burden well: it declares the tool is paid ($0.02 USDC/call), names the payment mechanism and network (x402, eip155:8453), and characterizes the output as signed, dated, and offline-verifiable. It stops short of saying what happens when certification fails (e.g., whether the fee is still charged or a failing attestation is issued), which matters for a paid 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?

Front-loads the price and payment metadata, then the action and the artifact, then the verification path; an agent can parse the essentials from the first two sentences. The closing line ('This is the difference between...') is mildly promotional but does contribute sibling differentiation, so it is not pure waste.

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 one-parameter paid tool with no output schema and no annotations, the description covers cost, payment protocol, output nature, intended use, and the free verification route — enough to call it correctly and set expectations. The remaining gaps (failure behavior, attestation validity window, response shape) are real but not blocking for invocation.

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% and the single `url` parameter is already documented with an example origin, so the schema does the heavy lifting. The description adds only the scoping notion of 'one agent' per call, with no constraints on redirects, subdomains, or non-HTTPS origins beyond the schema. Baseline 3 is appropriate.

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 concrete verb and resource — 'measure one agent' and return a 'signed, transportable attestation of its discoverability' — plus what the artifact is for (publish on site, give to a directory). It implicitly distinguishes itself from the unsigned scoring siblings by contrasting 'saying my agent is agent-ready' with 'proving it', but never names agent_ready_score or verify_attestation directly, so the separation from siblings takes inference.

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?

Conveys the use case (produce a verifiable proof artifact to publish or hand to a directory) and routes anyone who wants to check a certificate to the free POST /agents/certify/verify endpoint. It does not say when to prefer this over the cheaper/unsigned measurement siblings, nor whether it should be called before or after an agent-ready check, leaving the choice largely implied.

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