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

No annotations are provided, so the description must convey behavioral traits. It mentions billing (1 credit per call) but does not indicate side effects, permissions, response format, or any other operational nuances. For a search operation, it likely is read-only, but this is not stated.

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?

Description is short and front-loaded with the core purpose, followed by billing note. No redundant information; 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?

Tool is simple (2 params, no output schema, no annotations). The description covers the primary purpose and cost, but lacks information about response structure, error handling, or any prerequisites. It is adequate for basic use but not comprehensive.

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%, so the description must clarify parameters. It explicitly links 'phone number' to the 'number' parameter and 'country code' to 'code', providing basic semantics. However, it lacks format, length, or examples, which would be more helpful. Given the low coverage, this is a minimal but acceptable explanation.

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?

Description clearly states the tool searches for a contact using a phone number and country code, with specific resources and parameters. It differentiates from the sibling tool get_api_v1_getCountryCode, which likely retrieves country codes rather than searching contacts.

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?

No guidance on when to use this tool versus alternatives. The sibling tool exists, but the description does not mention when one should be preferred over the other. No exclusions or contexts provided.

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