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

Annotations only cover safety (readOnly/idempotent/openWorld); the description adds the crucial two-mode behavior: it returns a paid x402 request URL by default, but with a P0 bearer key it executes the paid call itself and deducts the price, plus that bad input is refused before any charge and pricing is $0.005/call. These are exactly the traits an agent cannot infer from the schema or annotations.

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?

Purpose and routing come first, then pricing/behavior, then alternatives and the key mode — a sensible front-loaded order with no filler. It is dense and the long key-purchase URL clutters an otherwise tight paragraph, costing a point.

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 covers what comes back (the exact paid request, response schema and example; or the data itself with a key) and the cost/no-charge-on-bad-input guarantees. It leaves the shape of a successful screening result (hit list fields, score meaning) to the referenced schema rather than describing it, so it is complete enough but not fully self-contained.

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 names, limits, ranges and the name/address either-or are already documented. The description restates the address-or-name choice but says nothing about limit or min_score, so it adds no meaning beyond the schema; baseline 3 applies.

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 and resource ('screen a wallet address or a person/company name against sanctions lists') and names the exact list coverage (OFAC SDN, UK, EU, Canada, US CSL). It explicitly distinguishes itself from sibling tools wallet_risk, token_risk and sanctions_screening_batch.

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 an explicit trigger ('before paying or trading'), names the alternative tools with their respective scopes, and routes batch use to sanctions_screening_batch. When-not-to-use is implied by 'Sanctions lists only' versus the broader risk-label siblings.

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