user_get_by_phone

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

No annotations provided, so description is the sole source. It only states 'find user' without clarifying if it is read-only, returns single/multiple users, or any other behavioral traits such as authentication requirements or potential side effects.

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 a single concise sentence, front-loaded with the core purpose. No redundant information, though more structure (e.g., bullet points) could improve clarity for complex use cases.

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 1-parameter lookup tool with no output schema, the description is minimally complete. It lacks return value details or error scenarios, which are somewhat acceptable given the simplicity, but could be more helpful.

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 0%, but the description adds meaning by stating the 'identifier' can be a phone number or email, which is beyond the schema's 'string' type. However, no format constraints or edge cases are mentioned.

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 'find user by phone number or email,' specifying the resource (user) and lookup method. It differentiates from sibling tools like user_get_card or user_get_friends by indicating the identifier type.

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. It implies use when you have a phone/email, but does not mention when not to use it or list alternative tools for other lookup scenarios.

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