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

Goes well beyond the readOnly/openWorld annotations: discloses deterministic exact-match semantics (CLEAR or HIT), the absence of clustering/risk scoring, a concrete cost ($0.01 USDC on Base), and the full x402 payment flow (402 → PAYMENT-SIGNATURE → delivery) including that the tool call itself is free. This is substantive operational context an agent cannot 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?

Front-loads the core action, then stacks the distinguishing details efficiently. Dense but each clause carries information; the title repetition at the start is the only mild redundancy.

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?

Despite no output schema, the description explains the return shape (CLEAR/HIT verdict plus the x402 URL to GET) and the payment handshake, so an agent knows both the outcome and next step. Nothing needed to invoke it correctly 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% and the single 'address' parameter is already documented as 'digital currency address to exact-match (required)'. The description's 'exact-match a blockchain address' reinforces rather than extends that, so the baseline of 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 precise verb+resource: exact-match a blockchain address against OFAC Digital Currency Address identifiers from the SDN XML. It explicitly distinguishes itself from the name-screen sibling by noting it's 'the same Treasury list we ingest for name screens', so an agent can route address vs. name screens correctly.

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?

Clear context for when to use it (blockchain address screening against OFAC) and what it is not (no chain intel, no clustering, no risk score). It references the sibling name-screen use case but never explicitly instructs 'use screen_sanctions_name for persons/entities', leaving that routing implicit.

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