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

Annotations already state readOnlyHint=true and openWorldHint=true, so the safety profile is covered; the description still adds real value beyond them by disclosing 'free, no key' (no authentication/credential requirement) and by noting it returns 'the reason when it cannot be read', an error behavior the annotations do not convey. It stops short of describing latency, caching, or how long a status stays valid.

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?

Two sentences, front-loaded with the precondition and the action, followed by the full status vocabulary and the failure behavior. Every clause carries information; nothing is redundant with the title or schema.

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?

With no output schema, the description correctly carries the return contract by enumerating all seven statuses plus the reason field. Combined with the read-only/no-key disclosure, an agent has enough to call and interpret it; only the behavior for non-private payments and the failure shape (e.g. whether reason is per-status) are left implicit.

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 the single parameter is documented, so the baseline would be 3. The description goes further by explaining the provenance of the value ('from its quote_proof', produced by a private prepare_payment), which tells the agent where to obtain it rather than just its type.

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 opens with a concrete verb and resource ('give the deposit_address from its quote_proof') and scopes it to payments prepared with private: true, then enumerates the states it returns. It is clearly distinguishable from generic status siblings, though it never names the non-private alternative (e.g. payment_run_status or intent_status) that an agent might otherwise pick.

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?

The precondition 'For a payment prepared with private: true' tells the agent when the tool applies, which is more than most definitions offer. However, it gives no explicit when-not guidance and does not route the agent to a sibling when the payment is not private, leaving selection among ~60 tools partly to inference.

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