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

With no annotations, the description carries the full behavioral burden. It usefully discloses a hard prerequisite (the binding requirement) and the cost (0.002 USDC), and the phrase 'only when' implies refusal otherwise. But it says nothing about failure behavior, what the certificate contains, or how the maximum_age_seconds policy is enforced.

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?

A single dense sentence that front-loads the core verb and constraints, with cost at the end. No wasted words, though the compression leaves semantic gaps that a slightly longer definition could close.

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 tool with nested required schemas, zero parameter descriptions, no annotations, and no output schema, the single sentence is not sufficient. It omits the policy semantics, the certificate's contents, and the failure/return behavior an agent needs to call this correctly.

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 description coverage is 0% and both parameters are nested required objects. The description maps three data subfields (observed_at, source_uri, content_sha256) to their intent and adds the '64-hex' format detail, which is genuinely beyond the schema. But the entire policy object, including the central maximum_age_seconds threshold, is left unexplained.

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 names a specific verb (Certify) and resource (freshness) with the exact binding conditions required to issue the certification. It is clearly distinguishable from generic siblings like attest or verify by the freshness/URI/hash semantics, though it does not explicitly name a sibling it is not. Purpose is clear but sibling differentiation is left implicit.

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?

It states a precondition (only when timestamp is bound to source URI and a 64-hex content hash), which is a form of when-to-use guidance. However, it does not explain when to prefer this over nearby tools like attest, verify, or service_sla_attestation, nor any exclusions. Usage is implied rather than routed.

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