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

Annotations already cover readOnly, idempotent, closed-world and non-destructive behavior, yet the description adds genuinely new context: the call is free and unauthenticated, incurs no USDC cost, and returns representative payloads rather than real carrier records. It stops short of stating whether the sample is static fixture data or a live-but-unscored response, which is the one remaining ambiguity.

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 short sentences with the cost and authentication status front-loaded, followed by the two shapes covered and the purchasing rationale. No sentence is redundant and nothing is buried.

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?

With no parameters and no output schema, the description carries the burden of explaining what comes back, and it does identify both response shapes (IdentityScreen and IdentityAssessment). A brief note on whether the sample data is synthetic or real would make it fully self-contained.

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 tool takes zero parameters, so there is nothing for the description to disambiguate and the baseline applies. It correctly implies the call takes no inputs by presenting the sample as freely obtainable.

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?

It names a specific resource ('Free, unauthenticated sample of identity/fraud responses') and explicitly states it mirrors the response shapes of two named siblings, screen_carrier_identity and check_carrier_identity. An agent can distinguish this preview tool from the real lookup tools without opening any schema.

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 gives a clear use case: run this before spending USDC on check_carrier_identity to see the paid response shape and judge data quality. It does not explicitly say what to do instead when real data is required (i.e. call the paid tool), but the sample-vs-real split is strongly implied.

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