Check an address before sending it funds (standard tier, $0.10)

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

Goes well beyond the annotations: discloses the x402 USDC-on-Base payment, the funding wallet, the max-price refusal, and the notable edge case that a 503 is not charged. It also decodes the verdict semantics ('danger' = sanctioned/scam/poisoning/burn, 'caution' = insufficient evidence, confirm with user).

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 purpose, then pricing, then verdict semantics, then payment mechanics — a logical order with no filler. It is dense and long-ish, but every clause carries operational information, so it stays just short of 5.

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 enumerating the returned verdict JSON fields (verdict, risk_score, reasons, checked, tier, price_usd, as_of). Combined with the pricing and failure-mode details, an agent has everything needed to call and interpret it.

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?

Single required parameter with 100% schema description coverage, so the schema already documents the address and its pattern. The description reinforces that the address is the recipient/contract/counterparty, but adds no format or validation detail beyond the schema — baseline 3.

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 and resource ('Screen an EVM address on Base') and pins the scope to the standard tier at a fixed $0.10, which cleanly separates it from the sibling check_address_risk_quick/deep and the generic check_address_risk. An agent can select it without opening any 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?

Gives an explicit trigger ('before sending it money or interacting with it') and names the alternative route ('use check_address_risk with tier="standard" if you want that price without a dedicated tool'). It also states a refusal precondition (price above VERDIX_MAX_PRICE_USD).

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