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

No annotations exist, so the description carries the full burden and does so richly: it discloses one-shot deterministic retrieval, that it drains only the pinned rendezvous relay, that mismatched DMs are deleted and NACK'd without revealing the expected phrase, and that the returned grant is self-verifying with nothing stored server-side. It also states the call is free. This is exactly the behavioral disclosure an agent needs for a non-idempotent, order-sensitive retrieval.

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-loaded with a one-line purpose before the flow and constraints, and every sentence carries information. Somewhat long with heavy emphasis formatting, but the length is justified by the stateful flow it documents rather than padding.

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?

Although an output schema exists (so return values needn't be explained), the description still clarifies the shape and lifecycle of the returned proof grant envelope and what the caller must do with it, closing the loop for a multi-step flow. Nothing an agent needs to call this 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%, so both params are already documented (baseline 3). The description adds genuine meaning beyond the schema: it names the concatenation key '(patron_npub, dpop_token)' and specifies that dpop_token must be the value returned by request_npub_proof, plus that the newly returned dpop_token must be carried on all subsequent paid calls.

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+resource ('Receive npub ownership confirmation from a patron') and explicitly positions itself within the npub-OWNERSHIP-PROOF flow, distinguishing itself from the 'credential-delivery counterpart' receive_credentials. An agent can tell exactly what this does and how it differs from its nearest sibling 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 explicit when-to-call ('Call this only after the user confirms they have replied'), an explicit anti-pattern ('If called before the user replies, their message will never be found. Do NOT poll, loop, or retry'), and names both related tools (request_npub_proof supplies the token; receive_credentials is the parallel flow). Nothing is left to inference.

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