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

No annotations are provided, so the description carries the full behavioral burden and does so richly: it discloses the pinned-relay drain scope, that mismatched DMs are deleted and NACK'd without leaking the phrase, that it is deterministic/one-shot, that the signed DM itself proves ownership, and that a new self-verifying grant token must be persisted and reused on every paid call.

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 action and the critical timing constraint (bolded), then layers the flow details. It is long, but for a multi-step, one-shot cryptographic flow nearly every sentence carries operational weight; only the 'Free.' tail and some re-statement are marginal.

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 values need not be explained, yet the description still tells the caller what to do with the returned token across subsequent calls. For a free, stateful, one-shot retrieval tool with no annotations, this is complete enough that an agent can invoke it correctly.

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% and both parameters already document their meaning, so the baseline is 3. The description adds the crucial relationship that dpop_token is the value returned by request_npub_proof and that the response is named by the (patron_npub, dpop_token) tuple, giving semantic linkage beyond the schema's single-line text.

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 — receiving npub ownership confirmation — and situates it in the npub-OWNERSHIP-PROOF flow, explicitly naming its credential-delivery counterpart receive_credentials. An agent can tell it apart from request_npub_proof and receive_credentials 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?

Explicit when-to-call ('only after the user confirms they have replied'), when-not-to-call ('If called before the user replies, their message will never be found'), and an anti-pattern exclusion ('Do NOT poll, loop, or retry'). It also names the prerequisite tool (request_npub_proof) and the sibling counterpart.

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