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

Annotations already flag destructive/idempotent/openWorld, but the description adds context they cannot: funds are real and irreversible once sent, and the idempotency key must be reused on retry after a timeout so funds are never sent twice. That is precisely the operational knowledge an agent needs before invoking a money-moving 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?

A single tight paragraph: flow position first, then the irreversible warning, then the idempotency rule, then the follow-up path. Every sentence carries non-redundant information and the highest-risk fact is front-loaded.

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 destructive, money-moving tool with no output schema, the description supplies the full lifecycle: prerequisite quote, parameter-matching rule, retry safety, and where to read the outcome (get_payout status/transaction_url or webhooks). Nothing an agent needs to call it safely 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 the baseline is 3, but the description adds cross-parameter meaning the schema cannot: destination_network and destination_address must be identical to the preview, and idempotency_key has a retry-reuse contract rather than just being a unique string. It stops short of describing external_id or destination_memo, which is acceptable given full schema coverage.

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 ('executes a preview_payout quote and sends real funds from your balance') and positions itself as step 2 of a flow, which cleanly distinguishes it from preview_payout and get_payout. An agent can identify the tool's role 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?

Gives explicit sequencing ('Step 2 ... executes a preview_payout quote'), a precondition (preview must not be expired, carried via preview_id), a constraint (destination fields must match the preview), and named alternatives for the follow-up path (get_payout vs webhooks payout.completed / payout.failed).

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