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

Goes well beyond the readOnly/openWorld/idempotent annotations by disclosing the data refresh cadence (weekly), the exact cost and payment path (0.003 USDC via x402 or 2 credits of a Factline API key), and the response contents. An agent knows the safety profile, the freshness of the data, and the billing implications before invoking.

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 dense sentences with the core purpose and data source front-loaded, and no filler. The chain enumeration and pricing details are packed closely but each clause carries information the agent needs, so it reads efficiently rather than padded.

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, and the description compensates by stating exactly what is returned (sanctioned true/false, currency, listed entity, programme). Combined with cost, freshness, and supported chains, everything needed to call and interpret the tool is present.

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 schema supplies an EVM example, so the baseline is 3. The description adds meaningful value by enumerating the supported chains/asset types (Bitcoin, Ethereum/EVM, Tron, USDT, Litecoin, Monero), telling the agent which address formats are accepted beyond the single 0x example.

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 (screen/check) and resource (crypto wallet address) and names the exact data source (US OFAC SDN list). It also resolves the naming mismatch with its eu_sanctions_* siblings by making clear this screens the OFAC list, not an EU list, so an agent can pick it 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?

Explicitly names the scenarios that select this tool ('wallets, exchanges, payout, crypto onboarding and agent payment flows: screen a counterparty before sending funds'). It gives clear context but does not state when NOT to use it or point to the sibling alternatives like eu_sanctions_screen for non-wallet screening.

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