decode_selector

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

No annotations are present, so the description carries full responsibility. It mentions resolving via 4byte.directory, implying an external API call, but does not disclose rate limits, authentication needs, or side effects. The acceptance of full calldata is a behavioral nuance, but overall transparency is low.

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 concise, consisting of one clear sentence and a clarifying phrase. It is front-loaded with the primary action. No unnecessary words, though structuring could be improved slightly.

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 a single parameter, no output schema, and no annotations, the description provides a minimum viable explanation of what it does and what it accepts. However, it lacks details on return format, candidate count, or potential errors, leaving some gaps for an agent.

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 schema covers 100% of parameters, with the parameter 'selector' described only as 'Function selector'. The description adds meaningful context by stating it accepts a bare selector or full calldata, which clarifies input flexibility 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 clearly states the tool resolves a 4-byte function selector to candidate human-readable signatures via 4byte.directory. It uses a specific verb 'resolves' and identifies the resource. However, it does not explicitly differentiate from sibling tools like contract_abi or tx_decode, which may have overlapping functionality.

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 does not provide guidance on when to use this tool versus alternatives. It mentions it accepts a bare selector or full calldata, but does not specify prerequisites, limitations, or when not to use it.

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