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 that signatureValid is only a signature integrity signal, not an authenticity/safety check, and mentions a disclaimer. It adds moderate context beyond the name, but lacks details on error handling or 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 extremely concise, with a single sentence for the primary action and a clear note about the return values. No wasted words, and the most important information is front-loaded.

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 lookup tool with one parameter and no output schema, the description covers the basic purpose and the key nuance of the return value. However, it omits the structure of the response, potential errors, and the format of identityId, leaving some gaps.

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%, yet the description provides no information about the identityId parameter (e.g., format, type beyond schema). It fails to compensate for the low schema coverage, leaving the agent with no guidance on how to provide the identity.

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 'Look up an identity' and specifies the return values (signatureValid and disclaimer), providing a clear verb-resource pairing. However, it does not differentiate from sibling tools like agent_identity_record, so it falls short of a 5.

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 explicit guidance on when to use this tool versus alternatives. The note about signatureValid not being an authenticity signal provides an indirect caveat but no positive selection criteria or comparison to other identity tools.

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