Is an area code a scam?

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

Without any annotations, the description fully discloses the tool's behavior: it returns context about scam association and spoofing notes, emphasizing that the area code itself is not indicative of a scam. No side effects or permissions are mentioned, but for a simple informational tool, this is adequate.

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: two sentences that front-load the purpose and add crucial nuance without any fluff. Every sentence adds value.

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 simplicity of the tool (one parameter, no output schema), the description is complete. It explains the core functionality, the caveat about spoofing, and how to use the result, leaving no obvious gaps.

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 already provides a clear description of the 'code' parameter (3-digit area code). The description does not add new parameter details but reinforces the context of what the tool returns, which indirectly aids understanding. With 100% schema coverage, a baseline score of 3 is appropriate.

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: to explain whether an area code is associated with scams. It also provides nuanced context that an area code is never a scam by itself and returns spoofing notes, distinguishing it from sibling tools like lookup_area_code or check_number_reputation.

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 implicitly advises when to use the tool (to check if an area code is scam-related) and provides guidance on how to interpret results: 'judge calls by what they ask for, not the area code.' It does not explicitly state when not to use but does offer clear context.

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