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

Annotations already declare readOnly/idempotent/non-destructive, and the description reinforces this usefully with 'without consuming the proof' and describes the return ('spent and its registry entry'). It also adds a genuine semantic warning that an absent entry is not proof of validity, which goes beyond the 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?

Two tight sentences with the core action front-loaded, followed by the return shape and a caveat. No filler.

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?

With no output schema, the description competently covers what is returned. The nested query parameter is left entirely to the schema, and there is no mention of error/not-found behavior, but the essential picture for calling this read tool is present.

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 both digest and the optional query object are documented in the schema. The description adds no meaning about the digest format or what query keys are accepted, 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 ('Inspect whether a proof digest is spent or revoked') and clarifies the read-only nature ('without consuming the proof'). Sibling affix_spent_revoke exists but is not named, so differentiation is only implied.

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?

Usage is implied by 'is spent or revoked' but there is no explicit when-to-use guidance or routing to affix_spent_revoke for the mutating counterpart. The closing caveat addresses interpretation of results rather than tool selection.

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