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

Annotations only declare readOnlyHint and openWorldHint; the description adds substantial context beyond them: the exact upstream API, the price ($0.002 USDC via x402 on three chains), the fact failed calls are not charged, and the fuzzy-matching option limited to the SDN portion. These are billing and behavior facts an agent could not infer from structured fields.

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?

Four sentences, no filler, and the most decision-relevant facts (what lists, what is excluded) are front-loaded before the pricing note. Every sentence carries information an agent needs.

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 an output schema present, return-value shape need not be described. For a paid, open-world lookup tool the description covers scope, exclusions, cost/failure billing, and result interpretation — nothing material is missing.

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%, so the baseline is 3; the description earns extra by clarifying that fuzzy matching applies only to the SDN half, not the UN list — a meaningful distinction the schema does not express. The character-length constraint on name is left to the schema, which is fine.

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 (name screening) against two named sources (US OFAC SDN and UN Security Council consolidated list) and explicitly carves out what it does not cover (crypto addresses, EU list). An agent can tell exactly what this returns — matching entries — without opening the 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 clear positive scope plus explicit exclusions ('does NOT screen crypto addresses', 'does NOT check the EU list'), which is strong routing guidance. It also frames the output semantics ('a lead for a human reviewer, not a legal decision'). It stops short of naming a sibling alternative for the crypto/EU cases, so a 4 rather than a 5.

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