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

Adds real context beyond the annotations: 'Nothing is sent yet and the quote is free' clarifies that the non-readOnly tool has no fund movement, and the expires_at / invalid_address behavior is disclosed. It doesn't discuss idempotency or retry semantics of the preview itself, but with annotations already covering safety and idempotency this is strong.

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?

Four compact sentences, each earning its place: purpose and step, return fields, safety/expiry, and error case. Front-loaded with the workflow role and the no-side-effect guarantee.

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?

No output schema exists, so the description carries the return values (preview_id, to_amount, fee, expires_at) and does so explicitly. Combined with the expiry, error case, and next-step guidance, an agent has everything needed to call this 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%, so baseline is 3, but the description adds a constraint not in the schema: the destination coin must have payout=true in list_assets. That is genuinely useful filtering guidance beyond the field definitions.

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 ('Quotes a payout of amount USDT from your balance to an address') and positions it as 'Step 1 of sending money', which cleanly separates it from create_payout and the other preview_* tools. An agent can tell exactly what this does 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 a clear workflow: check address and amounts, then call create_payout with preview_id before expires_at, and points to list_assets for valid destination coins. It does not explicitly say what to do if a valid preview already exists or warn against skipping the preview, so it stops short of full when/when-not coverage.

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