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

With no annotations, the description carries the full burden and does well: it discloses the resolver path (Ethereum mainnet Universal Resolver), CCIP-read/offchain support, and the payment model ('only pay for successful reads', $0.002 USDC on Base). It does not describe return shape or rate limits, but covers key behavioral traits beyond the schema.

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?

The description is two compact sentences with the core action and constraint front-loaded. The parenthetical and payment note are useful and not redundant.

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?

Given no output schema and no annotations, the description supplies resolver context, mutually exclusive parameters, and settlement behavior. It omits the exact return format, but for a simple resolution call the essential invocation details are present.

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, but the description adds a meaningful constraint not encoded in the schema: exactly one of 'name' or 'address' must be supplied. The paymentSignature parameter is documented only in the schema, which is acceptable given full schema coverage.

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?

The description states a precise verb ('Resolve') and resource ('ENS name to an address, or an address to its primary ENS name') and names the resolver mechanism. This clearly distinguishes it from generic address tools like chain_address_info.

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?

It gives explicit input selection guidance: 'Pass exactly one of name or address.' It does not name alternative sibling tools or state when reverse resolution is preferable, but the usage condition is unambiguous for calling it.

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