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

Annotations only say readOnly/idempotent/openWorld; the description adds substantially: verdict enum, 0–100 score, blocked flag, matching signals, and a critical negative caveat that a clear verdict is not a safety guarantee. It also discloses per-chain depth variance and which chains are list-match-only, plus that it is free with no API key.

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-loads the purpose and the verdict/return summary, then the caveats and chain support. Every sentence carries information, though the long chain-format enumeration overlaps with the schema's address description and could be trimmed.

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?

For a screening tool with an output schema, the description still summarizes the verdict, score, blocked flag, and signals, and explains the decisive interpretive limit of a clear verdict. An agent has everything needed to call it and to report results responsibly.

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 schema already explains address formats, network enum, and lang. The description adds the chain-depth caveat pointing at coverage.chains, which is useful context but not parameter-level detail beyond the schema. Baseline 3 applies.

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 (AML screen on a single blockchain address) and anchors it to a concrete moment: the pre-payment counterparty check. It names the exact data sources checked and the return shape, so an agent can distinguish it from siblings like screen_endpoint or check_payment_request without opening a 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?

Explicitly says when to call it: BEFORE paying or receiving from an address. The chain-support notes and the 'list matching only' caveat give practical preconditions. It stops short of naming alternative tools or when to prefer them, so it falls below a 5.

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