validate_identity

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

There are no annotations, and the description only states the check operation without disclosing return format, error behavior, or potential side effects. Since 'check' implies a read-only operation, the agent may infer safety, but the tool does not specify whether it returns a boolean, status object, or what happens on invalid input.

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 sentence that states the core purpose without extraneous detail. It is front-loaded with the action and resource, making it quick to parse.

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?

The tool lacks an output schema and annotations, and the description does not specify what the response looks like or any usage constraints. While it is a simple validation check, the absence of return semantics and edge-case behavior leaves the description incomplete for an agent to invoke with confidence.

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 provides 100% coverage with descriptions for both required parameters (phoneNumber and idNumber), and the tool description clarifies the relationship between them. The description adds no extra syntax or format details beyond the schema, so baseline 3 is appropriate.

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 uses a specific verb 'Check' and clearly defines the resource: whether a phone number is registered against a national ID number. This distinguishes validate_identity from sibling tools focused on payments/transactions, making the tool's purpose unambiguous.

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 implies the tool is for identity verification but provides no explicit guidance on when to prefer it over alternatives, nor any exclusions or prerequisites. No sibling tool is mentioned, leaving the agent to infer usage context from the tool name alone.

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