Phones Enricher

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

With no annotations provided, the description carries the full burden. It discloses a key behavioral trait (synchronous only, no async or webhooks), which is valuable. But it does not state whether the tool mutates data, requires specific authentication, or any rate limiting, so it's somewhat thin.

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 extremely concise: one purpose sentence, a list of use cases, and a note. Every sentence adds value and is front-loaded. There is no fluff or repetition.

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's simplicity (one parameter, no nested objects) and the presence of an output schema, the description covers the essentials: purpose, use cases, and a key limitation. It lacks some details like error handling or required permissions, but for this scope it is reasonably complete.

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 already describes the only parameter 'query' as 'One or more phone numbers to enrich.' The description adds no extra semantics beyond what is in the schema, so it does not improve on the 100% schema coverage baseline.

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 opens with a specific verb and resource: 'Enrich phone numbers using the documented /phones-enricher endpoint.' It also lists concrete use cases (carrier lookup, phone validation, message deliverability checks) that clearly distinguish it from sibling tools like emails_validator or businesses_search.

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 'Best for' section provides clear context on when to use this tool, and the note about synchronous-only execution adds a limitation. However, it does not explicitly name alternatives or give 'when not to use' instructions, so it falls short of a 5.

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