Phones Enricher

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

With no annotations provided, the description must carry the full burden. It clearly states the synchronous nature and the lack of async/webhook support, which is a key behavioral trait. Beyond this, it doesn't detail other behaviors like rate limits or data retention, but the explicit note on execution mode is a significant disclosure that goes beyond typical descriptions.

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 compact and front-loaded, leading with the core purpose and then listing use cases in a bullet-like format. The note on synchronous execution is appended at the end, preserving flow. Every sentence has a purpose, with 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 (single parameter, no nested objects) and the presence of an output schema, the description covers the essential aspects: purpose, use cases, and execution mode. It doesn't describe the return format, but since an output schema exists, that's not required. The lack of annotations is compensated by the synchronous note, and there are no missing pieces for an agent to make a correct call.

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 coverage is 100% for the single parameter 'query', which is described as 'One or more phone numbers to enrich.' The description adds value by implying that the query is about phone numbers and the purpose is enrichment, complementing the schema. It doesn't add extra syntax details, but the schema is already clear, so this is sufficient.

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 enrich phone numbers using a specific endpoint. It lists three concrete use cases (carrier lookup, phone validation, message deliverability checks), which are specific enough to differentiate from sibling tools like emails_validator or businesses_search, which deal with different data types.

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 provides clear use cases ('Best for:') without explicitly naming alternatives for when not to use it. However, the clear focus on phone-specific tasks implicitly distinguishes it from email or business tools. It also mentions the synchronous-only limitation, guiding the agent on execution expectations, which is valuable for usage decisions.

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