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

With no annotations, the description carries the burden and does well: it states the check is free, has no side effects, touches no relay, reads expiry from the grant itself, and consults only the patron's revocation watermark. It still omits details such as authentication requirements or rate-limit behavior.

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 description is front-loaded with the key purpose and then adds only useful operational context. Every sentence earns its place, and there is no redundant restating of the tool name or schema fields.

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 read-only status check with an output schema and no annotations, the description supplies the important behavioral context: cost, side effects, data sources, and intended preflight usage. It does not describe error or invalid-grant behavior, but the output schema likely covers return shape.

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 parameters are already documented in the schema. The description contextualizes dpop_token as the grant for the next paid call and mentions the patron revocation watermark, but it adds little formal meaning beyond the schema baseline.

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?

The description states a specific verb ('Check') and resource ('proof grant'), plus the exact validity question being answered. It distinguishes itself from nearby payment/balance checks by scoping to the npub-proof flow and the dpop_token used for paid calls.

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?

It clearly tells the agent when to use this tool: before a paid call, to avoid burning credits on a guaranteed failure, and it explains the analogous check_oauth_status flow. It does not explicitly list when not to use it or name a sibling alternative, so it falls short of the full 5.

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