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

Beyond the readOnly/idempotent/openWorld annotations, the description discloses genuinely operational traits: a hard 25-address capacity cap, the flagged-subset return behavior, a concrete pricing model ($0.03/call over x402 on Base), an unlimited prepaid x-credit-token path, a 1 free call/day tier, and no-API-key enforcement. These are exactly the traits an agent needs before committing a call.

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?

Front-loads the core action and scope ('Screen up to 25 addresses...') before moving to use case, required input, and pricing. Efficient overall, though the pricing/auth sentences are dense and could be trimmed slightly.

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 single-parameter batch tool with an output schema covering return values and annotations covering the safety profile, the description closes every remaining gap: capacity limit, format, cost, auth mechanism, and intended caller.

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 100% and there is only one parameter, so the baseline is 3. The description still adds value beyond the schema's 'Addresses (comma-separated)' by stating the hard 'up to 25' limit on the list length, which the schema does not encode.

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 a specific verb (Screen), resource (addresses against OFAC), and scope (up to 25 at once, batch). The batch framing implicitly distinguishes it from the singular sanctions/sanctions_name siblings, though it doesn't name them explicitly.

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?

Gives a clear use case: 'Built for compliance agents vetting whole counterparty lists in one call.' This tells the agent the right context for the batch tool, but it never names the alternative (single-address sanctions screening) or states when NOT to use it.

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