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

Annotations already declare readOnlyHint/idempotentHint/destructiveHint=false and openWorldHint=false, so safety is covered. The description adds real context beyond them: the call is 'Free', it recomputes a hash and recovers the signer, and it only works on the full response object passed unchanged. It stops short of describing failure modes (e.g., mismatch behavior) or auth needs.

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 cost note, then purpose, then when/when-not, then the input constraint. No sentence is padding; each clause carries a distinct decision-relevant fact.

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?

An output schema exists, so return-value semantics need not be spelled out; the description covers purpose, routing, and the input integrity requirement. For a single-parameter verification tool with an output schema, nothing an agent needs to call it correctly is missing.

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 'document' parameter is already documented as the complete signed answer with attestation. The description still adds a constraint the schema does not express — it must be the full response object, unchanged — which is exactly the detail that determines verification success.

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 — recompute the hash of a signed Settled response and recover the signer to test authenticity — plus the outcome ('tells you whether it is authentic and unaltered'). The 'not for answers you just received directly over this server' clause separates it from the fresh-answer path used by siblings.

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?

Explicit 'Use when' (a Settled answer arrived via a third party, cache, or log and you need to trust it) and explicit 'Not for' (answers just received directly over this server). The selection condition is stated, not inferred.

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