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

Beyond the readOnly/idempotent/destructive annotations, it discloses matching semantics (exact, case-insensitive on the full address), the negative scope of a 'clear' result (counterparties not covered), freshness signaling via lists_as_of, and the full payment profile: $0.001 USDC ($0.003 with owner_name) via x402 on Base, PaymentRequired on unpaid calls, and no charge for failures. This is exactly the context annotations cannot carry.

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-loaded with purpose and list coverage, and every clause carries information (routing, matching semantics, pricing, failure behavior). It is dense in a single block; light structural separation of routing vs. semantics vs. billing would improve scannability, but nothing is wasted.

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?

Given an output schema exists, the description does not need to detail return fields, yet it still names the composite risk levels and lists_as_of. Combined with the safety annotations, the payment mechanics, and the explicit sibling routing, an agent has everything needed to call this correctly and interpret a 'clear' result honestly.

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 baseline is 3, but the description adds real meaning: owner_name 'screens the owner's name and returns a composite risk (critical when the address is listed, elevated when only the name matched)' and doubles the cost. The address parameter's matching rule (exact, case-insensitive, full address) is also clarified beyond the regex.

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) and resource (blockchain wallet address) and enumerates the concrete list sources checked (OFAC SDN, OpenSanctions, UK, Circle USDC, Tether USDT, Ransomwhere). It explicitly distinguishes itself from screen_entity, create_travel_rule_packet, and verify_agent_identity, so an agent can route without opening sibling schemas.

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 a clear when-to-use ('before sending or accepting funds'), a conditional variant (owner_name for combined name screening), and names three alternatives with the exact condition that selects each ('for names alone use screen_entity', 'for a Travel Rule record create_travel_rule_packet', 'for an EVM agent's on-chain reputation verify_agent_identity'). Nothing is left to inference.

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