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

Annotations already cover readOnly/idempotent/non-destructive, and the description adds real value beyond them: it is free, requires no wallet or payment, and takes no arguments. The one gap is whether the returned sample is canned data or a live lookup, which matters for downstream trust in the output.

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?

A single sentence, front-loaded with the [FREE] tag and the reason it exists, followed by the payment and argument constraints. Every clause earns its place with no redundancy.

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 no-input preview tool with annotations carrying the safety profile, the description is nearly complete: it explains the cost model and the purpose. It does not describe the returned sample's structure, but given the tool exists specifically to let callers observe that shape, a modest gap remains.

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?

With zero parameters the schema is fully self-documenting, and the description reinforces this with 'no arguments needed', confirming the caller cannot and should not supply input. Baseline is 4 for a 0-param tool.

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 states a specific verb+resource: it returns a sample response for kyb_pack so the caller can see the shape before paying. It distinguishes itself from the paid kyb_pack sibling by naming it directly. Slight ambiguity remains about whether the sample is static or live, but the free-preview role is clear.

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?

It gives explicit when-to-use context: run this before paying 0.05 USDC for kyb_pack. It also states the preconditions (no wallet, no payment, no arguments), which is exactly the guidance an agent needs to avoid misfiring on the paid tool. No explicit 'what will not work' beyond cost/free terms, so not a 5.

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