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

Given non-read-only annotations, the description does the essential work of explaining why: 'Reads or computes only; not marked read-only because each call is charged,' which directly resolves the readOnlyHint=false tension. It also discloses concrete operating facts beyond the annotations — price ($0.03/call via x402 USDC or card key), first 25 free, failed calls free — that an agent needs 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?

Front-loaded with what the tool checks and the verdict it returns, followed by cost and the example, so the most important information comes first. The single dense paragraph packs pricing, payment rails, example and disclaimer together, which is slightly heavy but every sentence earns its place.

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 no output schema, the description must convey returns, and it does name the three verdict levels with reasons. It also covers supported chains, cost model and payment paths. Remaining gap: it doesn't describe the shape of the verdict payload or the factor list in detail, but for a screening aid this is close to complete.

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% (address described as '0x address to check', chain enum documented), so the schema already carries the parameter meaning. The description adds a worked example (address=0xd8dA..., chain=base) and notes Base-only heuristics, but adds little syntactic detail beyond the schema. Baseline 3 is appropriate.

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 (vet an EVM address) plus the exact sub-checks performed (OFAC SDN match, account type/activity, USD holdings, wallet risk heuristics, contract bytecode/proxy) and the output form (block/review/pass verdict with reasons). The phrase 'cheaper than buying the parts' tells the agent this aggregates sibling tools like sanctions_check, contract_risk and wallet_audit, distinguishing it clearly.

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 triggering scenarios: 'Use before paying, trading with or onboarding an address,' reinforced by the title. It bounds scope with 'Screening aid, not legal advice or a security audit,' but does not spell out when to prefer a narrower sibling (e.g. sanctions_check alone) versus this aggregate, so it stops short of full when/when-not coverage.

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