search_phone

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

With no annotations, the description carries the full burden. It states the tool is 'passive' and uses 'public-source collection', indicating non-destructive, read-only behavior. More detail on rate limits or error handling would improve it.

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?

Three concise sentences front-load the core purpose, followed by format and usage restrictions. No wasted words.

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 simple tool (2 params, no output schema), the description covers input format, authorization, and tool behavior. It could mention the type of data returned (e.g., carrier name, location), but is otherwise 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?

Schema coverage is 50%, but the description adds 'Use E.164 format' for the phone parameter, which is not in the schema. The json_output parameter has a description in the schema, so the overall meaning is enhanced.

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 verb ('gather') and resource ('carrier and geolocation data for a phone number'), and distinguishes from siblings like search_email and search_username by specifying the use of phoneinfoga.

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 includes format requirements ('E.164') and authorization conditions ('Authorized use only'). While it doesn't explicitly name alternatives, the sibling tools cover different data sources, making the context clear.

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