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

Annotations already declare readOnlyHint=true, so the description adds value by disclosing additional behavior: reverse lookup capability, avatar text record availability, and the mainnet-only restriction. It does not contradict annotations and goes beyond basic safety hints, but stops short of describing edge cases like unregistered names or error handling.

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, each with clear purpose. The core resolution is stated first, followed by the avatar addition and network constraint. No fluff or repetition; it is both concise and well-structured.

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 single-parameter tool with an output schema, the description covers all essential aspects: the input formats (name/address), the output direction (address/primary name), the avatar record, and the network (mainnet). The presence of an output schema means return value details are already provided, so the description is fully sufficient.

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 parameter is already fully documented in the schema. The description essentially restates the same info ('ENS name' or 'Ethereum address') without adding new semantics. Baseline 3 is appropriate when the schema does the heavy lifting.

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 uses a specific verb ('resolve') and clearly defines the resource (ENS names/addresses). It covers both forward and reverse resolution, which distinguishes it from sibling tools like balance checkers and transaction fetchers. The mention of avatar records and mainnet-only adds specificity without ambiguity.

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 description implies its use case by explaining exactly what it does, and the 'Mainnet only' constraint provides a clear exclusion. However, there is no explicit 'use this when' statement or mention of alternatives, though no sibling tool directly overlaps with ENS resolution.

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