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

With no annotations provided, the description carries the full burden and does well: it declares the call is free, side-effect free, touches no relay, and consults only the patron's revocation watermark while reading expiry from the grant itself. It omits auth requirements and rate-limit behavior, so not exhaustively transparent.

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 core purpose in the first sentence, then adds qualifying context. Every sentence carries information, though the mid-paragraph explanation runs slightly long.

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 explanation is unnecessary, and the description covers cost and side-effect profile. Combined with 100% schema coverage and no annotations, it is nearly complete, missing only auth/permission context.

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%, so both parameters are already documented (dpop_token from receive_npub_proof, patron_npub). The description adds contextual framing about what the token represents but no syntax or format detail beyond the schema, making the baseline 3 appropriate.

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') and situates it in the npub-proof flow by naming the analogous check_oauth_status. An agent can tell exactly what this tool returns a verdict on without opening the 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 clear trigger condition ('before burning credits on a guaranteed failure') and frames it as a pre-flight check for a paid call. It does not explicitly name an alternative or a when-not-to-use case, so it stops short of full 5-level routing guidance.

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