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

Annotations only declare readOnlyHint=true; the description adds meaningful behavioral context beyond that — it names the server-side checks performed (signature, expiry, revocation) and states 'Public endpoint — no API key required', which affects how an agent may call it. It does not contradict the readOnly annotation.

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?

Three tight sentences, front-loaded with the core action, followed by the checks performed and then the optional-parameter and access notes. No filler or redundancy.

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 two-parameter, read-only validation tool with no output schema, the description covers purpose, checks, optional filtering, and access. The only gap is that it doesn't describe the shape of the validation result, though the schema hints at a valid/reason structure.

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 100%, so the schema already documents both proof_token and identifier in detail (including the identifier_mismatch and identifier_unverifiable outcomes). The description restates the identifier purpose at a high level but adds no syntax or format detail beyond the schema, so baseline 3 applies.

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 ('Validate a proof token') and enumerates the concrete operations performed: signature, expiry, and revocation checks. This distinguishes it from siblings like get_proof_status, revoke_proof, and list_revoked_proofs without ambiguity.

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 implies usage (validating a token you hold) and explains the optional identifier check, but never states when to prefer this over get_proof_status or verify_delegation, nor any exclusion conditions. Usage context is implied rather than explicit.

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