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

Annotations already declare the tool read-only and non-destructive, and the description adds useful behavioral context: the return includes a name, a signature, and a tier indicating whether the match came from a verified ABI or a heuristic table. It stops short of explaining failure behavior when no match is found, but this is a strong addition given no output schema.

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?

A single sentence that is front-loaded with the core purpose and immediately follows with the tier detail. Every clause earns its place, with no redundant or filler content.

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?

For a low-complexity, one-parameter resolver, the description is largely complete: it identifies the input, the output components, and the provenance tier. The only notable omission is handling of unknown selectors or exact input formatting, but the overall picture is clear enough for an agent to invoke the tool confidently.

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?

Although the schema provides only 'selector' as a generic string with 0% description coverage, the description compensates by clarifying it must be a 4-byte function selector. It does not explicitly state the expected hex format or 0x prefix, but for a single simple parameter this is a meaningful semantic improvement over the bare 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?

States a specific verb ('Resolves'), a precise resource ('4-byte function selector'), and the result ('name and signature'). It also distinguishes itself from siblings like resolve_identifier by focusing on selector-to-signature resolution and mentioning the verified-ABI versus heuristic-table tier.

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 no explicit guidance on when to use this tool instead of siblings such as resolve_identifier, nor does it state when not to use it. Usage must be inferred entirely from the function of resolving a selector; there are no prerequisites, exclusions, or alternative routing signals.

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