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

Annotations already declare this is a non-read-only, idempotent, non-destructive, open-world call, so the safety profile is covered. The description adds valuable context the annotations lack: the response shape (deposit_address/deposit_memo/amount) and the expires_at deadline the payer is bound to. It stops short of describing what happens on expiry or duplicate external_id conflicts.

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?

A single front-loaded sentence with no filler, opening on the verb and resource. The trailing return-value clause is slightly dense with nested parentheses, but each element is informative rather than redundant.

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?

There is no output schema, and the description compensates by enumerating the key return fields and the payment deadline. Combined with fully documented parameters and clear annotations, an agent has enough to call it correctly; only edge-case behavior (expiry, retry conflicts) is unstated.

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%, with each parameter documented including the idempotency_key retry semantics, so the schema carries the load. The description only reinforces that credit_lock_id originates from preview_payment, adding no syntax or constraint detail beyond the schema. Baseline 3 applies.

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 ('Creates a payment') and names the exact input source ('from a preview_payment quote'), which cleanly separates it from the sibling preview_payment. The return contract (deposit_address, deposit_memo, amount, expires_at) further pins down what this call produces.

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 description makes the workflow prerequisite explicit by tying the call to a preview_payment quote, so an agent knows it must preview first. It does not, however, exclude adjacent options such as create_payout or create_conversion, nor state what to do if the quote has expired.

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