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

Annotations only declare it is not read-only, not destructive, and closed-world. The description goes well beyond that: it discloses where the record is persisted (payments/<request_id>.md and the deal's log), that both are updated once paid, and that hashn never custodies the money. That persistence and custody disclosure is exactly the added value structured fields do not carry.

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 core action leads the first sentence, and the following two sentences fold parameter meaning and side effects into compact prose. Slightly dense with backtick-interleaved parameter talk, but no sentence is wasted.

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 mutation tool with no output schema and 6 parameters, the description covers preconditions, parameter intent, and post-write storage effects. Return details are unnecessary without an output schema, and the auth path is already carried by the api_token schema field.

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 the baseline is 3. The prose largely restates the schema (deal path, memo uniqueness, amount format, pay_to being network-agnostic) with only marginal additions such as the /deals/protocol reference and the deal being agreed by all parties.

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 with directionality: 'Ask another party to an agreed deal to pay you.' This cleanly separates it from the sibling 'pay' (which sends funds) and from 'payment_status'/'list_payment_requests'/'cancel_payment_request', so an agent can route correctly 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?

It gives the key precondition that every payment belongs to an agreed deal (agreed by all parties, referencing /deals/protocol) and that memo must be unique within the deal, which is real usage context. It stops short of explicitly contrasting with the 'pay' sibling or stating when not to use it, so it is context-rich but not fully routing-aware.

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