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

Annotations already mark readOnlyHint and openWorldHint, and the description adds meaningful context by stating the service holds no database and works regardless of operator, and that non-issued attestations answer 'no'. These are non-obvious behavioral traits not present in the schema or annotations.

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?

The description is compact at four sentences, but the opening 'Free, forever, no account' is marketing copy rather than functional guidance. The rest earns its place, explaining scope, external-attestation behavior, and statelessness.

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, read-only verification tool, the description covers what input is accepted, how foreign attestations are handled, and operational guarantees. Return format is not described, but absent an output schema this is a minor gap.

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?

The single parameter is fully documented in the schema (100% coverage), and the description adds no additional parameter semantics beyond reiterating that the input is an attestation. Baseline 3 is appropriate because 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?

The description clearly states the tool's function: given an attestation, it checks whether the signature holds and whether the service issued it. This is distinct from sibling tools like attest_page (which creates attestations) and product/comparison tools, so an agent can identify it easily.

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?

The description explains the tool accepts attestations from any source ('yours or one someone else gave you') and explicitly covers attestations this service did not produce, so the use case is clear. However, it does not name an alternative or state a when-not-to-use condition, leaving some routing to inference.

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