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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive. The description adds cost and auth context not in the structured fields: free, no wallet, no payment, no arguments. It does not describe the sample payload's contents, but the cost/auth disclosure is genuine added value.

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] marker. It is efficient, though the "(OFAC sanctions screen)" parenthetical partly duplicates the title and the phrase is slightly dense.

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 preview tool whose entire purpose is to reveal the response shape, there is no output schema and the description never says what the sample actually contains. It conveys the cost model but not the payload an agent would use to decide whether to call the paid tool.

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?

Zero parameters, so the baseline applies. The schema covers the (empty) parameter set fully and the description correctly notes 'no arguments needed', leaving nothing ambiguous.

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?

States exactly what it is: a free sample response for sanctions_screen (OFAC sanctions screen), explicitly framed as a preview before paying. This cleanly distinguishes it from the paid sibling sanctions_screen and the other *_preview tools.

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?

"See the shape before paying 0.006 USDC" gives clear context for when to reach for this tool versus the paid sanctions_screen. It stops short of explicit when-not guidance (e.g., that it returns sample data unsuitable for real screening), so it is clear but not fully routed.

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