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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint, so safety is covered. The description adds genuinely useful context beyond them: per-name pricing, the underlying lists and their weekly refresh cadence, fuzzy-matching behavior for spelling/word-order variants, and the payment/auth routes (x402 USDC or a Factline API key). This is exactly the kind of operational disclosure the annotations cannot carry.

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 dense paragraph but well front-loaded: purpose and scope lead, then matching behavior, then use cases and cost. Every sentence contributes information (lists, matching, output shape, price); it is tightly packed rather than padded, though the nesting of cost details slightly crowds the flow.

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 output schema, the description usefully describes the return shape (per name: possible match flag, top score, up to 3 scored matches with their lists). Combined with payment details, list sources and refresh cadence, it is nearly complete; only the 'type' parameter's effect remains under-specified.

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 description coverage is 50%: 'names' is documented in the schema (1-25, ';'-separated) and the description mostly repeats the 25-name cap. It does add the person/organisation distinction that maps to the undocumented enum 'type' parameter, giving it partial meaning, but the enum itself is never named or explained. Baseline 3 is appropriate.

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) and resource (EU/UN/UK/US OFAC sanctions lists) with explicit scope: batch, up to 25 names per call. The 'batch' framing and the 25-name limit distinguish it from the single-name sibling eu_sanctions_screen without the agent needing to open either 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?

Gives clear usage contexts (customer onboarding, payouts, vendor/payment screening agents), so the agent knows the scenarios it serves. It does not, however, explicitly say when to prefer this over the singular eu_sanctions_screen sibling or note any exclusions, so routing between the two is left to inference from the name.

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