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

Annotations already establish that this is a read-only, idempotent, non-destructive, open-world call. The description adds crucial behavior beyond that: it is a paid tool costing $0.01 USDC on Base, requires a two-step x402 payment flow, and returns specific verdict 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 dense sentences with zero waste: purpose is front-loaded, return values follow, then usage trigger, then payment mechanics. Every sentence earns its place and supports correct invocation.

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 supplies the return shape (sanctioned true/false, verdict, SDN entity name, sdnType, programs, publish date). It also covers cost, payment protocol, and usage context, so an agent has everything needed to call it correctly.

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 schema already documents the sole address parameter, including format examples. The description still adds value by naming supported chains beyond the schema examples (XMR, every chain OFAC lists).

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 (screens) and resource (crypto wallet address) against a precisely named source (US Treasury OFAC SDN list), and enumerates supported chains. It is clearly distinguishable from all siblings, which cover DNS, email, URL, and whois checks, not sanctions screening.

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: use when about to send funds to, pay, or accept funds from an unfamiliar wallet. It does not name alternatives or when-not cases, but no sibling tool overlaps with this function, so the guidance is contextually clear.

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