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

readOnlyHint=true already tells the agent this is a non-mutating preparation step, so the bar is lower. The description still adds real value by enumerating what the server does NOT check (exchange rate, capacity, balance, allowance, preview state), warning the agent that the returned plan can fail on-chain and that pre-validation is its responsibility.

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?

Two sentences, zero filler, with the operation and its denomination front-loaded before the caveat. Nothing could be removed without losing signal.

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 five-parameter preparation tool with an output schema and annotations, the description covers the operation, the amount denomination, and the critical unverified-state caveat. It leaves the sibling relationship with prepare_sky_savings_redeem implicit, which is the main remaining gap.

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 schema already documents all five parameters including the exact-USDS-vs-shares semantics of 'amount' and the owner/receiver defaults. The description's 'exact USDS amount' phrasing reinforces that but adds no syntax, unit, or defaulting detail beyond the schema.

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 ('Prepare a direct sUSDS ERC-4626 withdrawal') plus a scoping detail, 'for an exact USDS amount', which implicitly separates it from prepare_sky_savings_redeem (share-denominated). It never names that sibling, so the distinction must be inferred from ERC-4626 knowledge rather than read directly.

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 'exact USDS amount' framing implies when this tool is appropriate versus the redeem variant, and the second sentence implies the caller must have verified state beforehand. There is no explicit when-to-use/when-not statement and no named alternative, so routing is only implied.

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