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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. The description adds valuable non-annotation context: the per-call cost ($0.008 USDC via x402) and the 20-address batch limit. It still omits return-shape and rate-limit behavior, keeping it below a 5.

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?

Three tight sentences, front-loaded with what it screens and against what list, followed by the batch limit, the use trigger, and the cost. Every sentence carries actionable information with no filler.

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?

No output schema exists, so the description would ideally hint at what a screening result contains (hit/no-hit, risk level). It compensates well with data source, chain coverage, batch limit, and pricing, leaving only the return-value shape unspecified.

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 100%, so the single 'address' parameter is fully documented in the schema itself. The description's 'up to 20 addresses per call' reinforces the batch constraint but adds no new syntax or format detail beyond what the schema states.

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+resource (sanctions screening for crypto addresses) plus the authoritative data source (US Treasury OFAC SDN list) and enumerates supported chains. An agent can distinguish it from siblings like address_verify or kya 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?

Provides a clear triggering context: 'Check before your agent sends money,' which tells the agent when this tool is relevant. However, it names no alternative (e.g., address_verify) and states no exclusions, so it stops short of full when/when-not guidance.

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