eth_selector

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

With no annotations, the description should disclose behavioral traits such as input validation (e.g., does it accept whitespace?), error handling, or output format. It only states the core operation without any edge-case behavior or side effects. This is insufficient for an agent to anticipate all outcomes.

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 sentence, which is concise, but it is too minimal for a tool with two parameters and no output schema. It sacrifices necessary details for brevity, making it insufficiently informative. A better balance would include parameter explanations and output specifications.

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 technical nature of the tool and lack of output schema, the description omits critical details: the return format (hex string?), error behavior for invalid signatures, and the difference between function and event signature syntax. An agent would need external knowledge to use this tool correctly.

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 0% description coverage, and the tool description does not explain either parameter. 'signature' and 'kind' are not defined, leaving the agent to guess the correct format (e.g., 'transfer(address,uint256)'). The default for 'kind' is mentioned in the schema but not in the description, adding no value.

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 clearly states the tool's purpose: deriving a 4-byte function selector or 32-byte event topic from a signature. It specifies the resource (signature) and the output type, making it easy to understand what the tool does. While it does not explicitly differentiate from siblings, the unique Ethereum ABI focus is implied.

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 'hash' or 'eth_hash'. It does not mention prerequisites, such as the signature format, or when to prefer 'function' vs 'event'. The agent receives no context for appropriate invocation scenarios.

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