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

No annotations, so the description carries the full burden, and it does well: it discloses pricing ($0.002 per call), accepted payment methods (USDC on Arc/Base/Solana, XNT on X1), the auth/settlement flow, and a behavioral guarantee about reverse-record filtering. It omits failure modes and invalid-input 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 tight sentences, front-loaded with the core purpose before pricing and the call protocol. Every sentence carries information; density is high but nothing is padded.

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?

With no annotations and no output schema, the description supplies purpose, cost, payment protocol, and a key output constraint. It leaves error handling and exact return shape unspecified, which is a minor gap for this level of complexity.

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. The description adds beyond the schema by clarifying the forward-verification guarantee that constrains what the address lookup returns, and by explaining the payment parameter's role in the call sequence (terms vs. settled purchase).

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 (resolve ENS on Ethereum) and covers both directions: .eth name to address and address to primary ENS name. It also carves out a distinct guarantee (forward-verified) that separates it from the generic evm_* siblings.

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?

Explicitly describes the two-step payment flow: call once without payment for terms, sign with your wallet, call again with payment. It also notes name-vs-address selection. It stops short of naming sibling tools or stating when another lookup tool is preferable.

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