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

With no annotations, the description carries the full burden and does so thoroughly: discloses the $0.01/call cost, the 1% native-coin platform fee priced into the transaction, non-custodial execution, the two-step x402 payment requirement, and the charge-only-on-result policy. This is substantial behavior beyond what the schema reveals.

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?

Every sentence earns its place: cost, purpose, fee, two-call workflow, and charging condition are all necessary operational facts. The description is dense but logically ordered and contains no filler or redundant restatement of schema fields.

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 paid, two-step swap tool with no output schema, the description covers the essential context: cost, fee, taker requirement, payment flow, and what comes back (a transaction and an accepts array). Exact quote/tx field details are not specified, but an agent has enough to invoke the tool 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?

The input schema already documents all 7 parameters at 100% coverage with detailed descriptions, so the tool description does not need to add per-parameter meaning. It reinforces that taker means the user's own wallet and that ref affects the fee, but it adds no new parameter semantics beyond the schema. Baseline 3 is appropriate.

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 action and deliverable: an executable KyberSwap-routed quote plus a ready-to-sign transaction for the taker's OWN wallet. The word 'Executable' and 'non-custodial' clearly separate it from a price-only tool like swap_evm_price, so an agent can distinguish 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 when-to-call guidance: call once WITHOUT x402_payment to receive the x402 payment requirements, pay one of them, then call again with x402_payment set. It also warns the tool is PAID and only charges when a result returns. It does not name alternatives or exclusions, but the invocation context is clear.

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