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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely new behavior: the commercial model (free within a daily allowance, then $0.002 USDC per call via x402) and the specific source list (OFAC SDN), which tells the agent the result is authoritative for US sanctions only.

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?

Two short sentences with the purpose front-loaded and the cost caveat second; no filler. The first sentence is a grammatical fragment ('Whether a crypto address ... is listed'), which is slightly awkward phrasing, but the information density is high.

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 covering return values and annotations covering safety, the description supplies the remaining essentials: what is checked, against which list, which chains are supported, and the pricing model. The one real gap is routing relative to the sibling sanctions screening tools.

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% with a single 'address' parameter, so the baseline is 3. The description does add value by enumerating the supported chains/formats (BTC, ETH/EVM, TRX, USDT and others), but it gives no format syntax or normalization guidance beyond that.

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?

The description states a specific resource (a crypto address) and the exact check performed against the OFAC SDN list, plus the asset families supported (BTC, ETH/EVM, TRX, USDT). It does not, however, differentiate itself from the sibling screening tools (sanctions__screen, sanctions__screen-us, sanctions__entry), so an agent must infer that this one is wallet-only.

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?

There is no when-to-use guidance and no reference to alternative tools. Nothing tells the agent when to pick wallet-screen over sanctions__screen or sanctions__screen-us, nor whether an address must be pre-normalized. Only pricing, not selection context, is provided.

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