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

No annotations are provided, so the description carries the full burden of behavioral disclosure. The description mentions bidirectional resolution ('<->') and avatar support, which is useful, but it doesn't disclose what happens with invalid inputs, whether it returns multiple records, rate limits, or any side effects. Since it's a read-only lookup, the lack of destructive behavior is implied but not explicitly stated. The description adds some context but leaves significant behavioral gaps.

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 a single, concise sentence that front-loads the core purpose. It's efficient and avoids unnecessary words. However, it could be slightly more structured by explicitly stating the input format and output, but for a one-line description, it's appropriately sized.

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 the tool has an output schema (though not shown in detail), the description doesn't need to explain return values, but it should clarify the input format and the bidirectional nature. The description is too terse for a tool with a single undocumented parameter and no annotations. An agent would likely need to experiment to understand whether 'q' accepts an ENS name, an address, or both, and what the output structure looks like. The presence of an output schema helps, but the description still lacks critical usage context.

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 0%, and the only parameter 'q' has no description in the schema. The tool description mentions 'ENS name <-> ETH address + avatar' but doesn't explain what 'q' should contain: is it an ENS name, an address, or either? The description partially compensates by implying the input is an ENS name or address, but it doesn't clarify the expected format (e.g., 'vitalik.eth' vs '0x...'). With 0% schema coverage, the description should do more to define the parameter semantics.

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 'ENS Resolve: ENS name <-> ETH address + avatar' clearly identifies the tool's function: resolving between ENS names and Ethereum addresses, with avatar support. It uses a specific verb ('Resolve') and resource ('ENS name <-> ETH address'), which distinguishes it from generic lookup tools. However, it doesn't explicitly differentiate from sibling tools like 'ethaddr' or 'ethcontract', which may also handle Ethereum-related lookups, so it's clear but not fully differentiated.

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 provides no guidance on when to use this tool versus alternatives like 'ethaddr' or 'ens' siblings. It doesn't state whether it's for forward resolution (name to address), reverse resolution (address to name), or both, nor does it mention any prerequisites or limitations. An agent would have to infer usage from the schema and context, which is insufficient.

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