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

Goes well beyond the annotations (readOnly/openWorld/idempotent/non-destructive) by disclosing latency (0.2-1 s), price (USD 0.002), the shared 10-reads/day free pool, the forward-verification of reverse records via `verified`, and an untrusted-data warning. These are exactly the behavioral traits an agent cannot infer from structured fields.

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?

Front-loaded with the purpose and input contract, then layers in the reverse-verification nuance, cost/quota, and safety warning. It is dense but every sentence carries distinct information; only the shared-pool parenthetical is slightly over-detailed.

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 output schema, the description partially compensates by explaining the `verified` field's meaning and the spoofing risk. Combined with cost, quota, and latency it is nearly complete, though the full shape of the returned record is not described.

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% and each parameter already documents the 'give name XOR address' constraint, so the schema does the heavy lifting. The description restates the same XOR rule without adding format or syntax detail beyond it, which is the baseline 3 case.

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 (resolve) and resource (ENS name or address) with scope pinned to Ethereum mainnet. An agent can distinguish this from read-only lookups like get_ens_records because the description names both the forward and reverse resolution modes explicitly.

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?

Gives clear context on which input to supply (name XOR address) and what each path does, so the agent knows how to invoke it. It stops short of naming alternatives (e.g. get_ens_records) or stating when-not to use this tool, so no exclusions are offered.

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