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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses the $0.01 USDC payment on Base, the payTo address, the reliance on public HTTP resolvers, and the behavior for unresolved names (resolved:false after payment). This gives an agent important operational context beyond the annotations, though the exact payment mechanism is not fully specified.

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 sentences carry all critical information without fluff: payment, purpose, resolver type, unresolved behavior, and the exclusion of the registrar. The ordering is slightly unconventional (payment before purpose), but each sentence earns its place.

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?

The description covers payment, chain, resolver, unresolved behavior, and an alternative endpoint, which is substantial. However, it does not describe the return format for a successful resolution (e.g., what resolved:true includes) or the exact steps to complete payment, and there is no output schema to fill that gap.

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% and the schema description already documents the name parameter. The tool description reinforces the requirement to end in .eth and clarifies that Basenames like foo.base.eth are also valid, adding a small but useful nuance beyond the schema.

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 names a specific action ('resolve an ENS or Basename') and a concrete resource (the name), with the required format. It also distinguishes itself from the registrar endpoint ('Not POST /name'), so an agent can tell it apart from sibling tools 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 gives clear context: it is a paid lookup using public HTTP resolvers, and it explicitly says it is NOT the registrar endpoint, which is a direct when-not case. It does not compare itself to sibling lookup tools like name_lookup or who, but the registrar exclusion is a strong usage signal.

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