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

Annotations already declare idempotentHint=true, openWorldHint=true, and destructiveHint=false, so the bar is lower. The description still adds real context beyond them: the result is a time-limited lock ('valid until expires_at') that is consumed by create_payment, which explains why a quote tool is marked readOnlyHint=false. It doesn't mention auth or rate-limit behavior.

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?

Three short sentences, each doing distinct work: what it is, what it returns and the downstream handle, and the sibling recommendation. The routing advice is placed last, after the agent already knows what the tool does.

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, but the description covers the key return fields (credited USDT, credit_lock_id, expires_at), which is exactly what the agent needs to chain into create_payment. With 100% schema coverage and clear annotations, nothing material 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 schema already documents amount, amount_atomic, asset_id, and idempotency_key in detail. The description adds only the framing that the amount is what the payer sends in a single coin; it says nothing about the amount vs. amount_atomic exclusivity or idempotency, so 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 ('quotes a payment of an exact amount in one coin') and what comes back ('how much USDT you will be credited'). It explicitly positions itself as a low-level alternative to invoices, which separates it from create_invoice, preview_conversion, and preview_payout without opening any 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 an explicit routing rule: 'Most agents should use create_invoice instead,' plus the handoff to create_payment via credit_lock_id. It stops short of stating the positive condition under which an agent should actually prefer this tool (e.g. need for an exact-amount, single-coin quote), leaving that to inference.

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