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

With no annotations, the description carries the full burden and does well: it declares the call is free, has no side effects, touches no relay, and only consults the patron's revocation watermark while reading expiry from the grant. It stops short of describing any auth/permission requirements for the caller.

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 one-line purpose is front-loaded, followed by supporting rationale and a safety note. It is appropriately sized, though the mirroring sentence is slightly wordy for the value it adds.

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 detail is not needed. The description covers purpose, usage rationale, and side-effect profile, leaving only the minor gap of caller authentication requirements.

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%, and both parameters (dpop_token, patron_npub) already carry required-status and provenance descriptions in the schema. The description adds no parameter-specific syntax or format guidance, so the 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: "Check whether a proof grant is still valid." It also positions itself against the sibling check_oauth_status by naming the distinct npub-proof flow it covers, so an agent can tell the two apart without opening a schema.

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?

Gives a concrete decision context: ask before making a paid call so you don't burn credits on a guaranteed failure. The "mirrors check_oauth_status" line implicitly routes OAuth-flow callers to the other tool, but there is no explicit when-not or full alternative enumeration.

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