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

With no annotations, the description carries the behavioral burden. It usefully discloses that this is a paid operation ($0.01 USDC Base x402) and that it is limited to on-chain L1 records, excluding CCIP. It does not describe error behavior or return formatting, but the core behavior is clear.

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 adding distinct value: the primary operation, the data-source limitation, and the cost. Everything is front-loaded and there is no filler or repetition.

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 simple resolvable tool, the description specifies the input kind, output type, scope limitation, and cost. It lacks detail on invalid names or address formatting, and the empty input schema leaves the exact request shape ambiguous, but the description is still adequately complete for a low-complexity tool.

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 has zero defined properties and 100% schema description coverage, so the baseline is 4. The description adds meaning by showing the expected style of input through the 'vitalik.eth' example, even though the schema itself does not name a parameter.

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 opens with 'ENS resolve: turn a .eth name into a 0x address,' which is a specific verb, resource, and output. The example 'vitalik.eth' makes it concrete, and the function is clearly distinct from the sibling tools base_gas and base_price.

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 provides clear scope: on-chain L1 records only, with an explicit 'no CCIP' exclusion, which helps an agent decide when this tool applies. It does not explicitly compare against base_gas/base_price, but their purposes are sufficiently different that no conflict arises.

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