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

Beyond readOnlyHint/openWorldHint, the description discloses the paid x402 handshake, the exact price (0.003 USDC on Base), that data is read live from a specific on-chain registry, and the categorical verdict scale. The read-only GET is consistent with readOnlyHint, so there is no contradiction.

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 provider, price and scope, then the return list, then the input example and the payment sequence. Every element is relevant, though the raw HTTP endpoint adds little for an agent already invoking the tool and the sentence is dense enough to read as one long block.

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 carries the return contract itself: found/UNREGISTERED, owner wallet, owner_is_contract, owner_tx_count, USDC balance, agentURI, registration metadata, risk flags and verdict. It also fully documents the two-step payment flow an agent must perform to get a result.

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 both fields are already documented, but the description adds real meaning: q is a JSON-encoded agentId payload and x_payment is only to be supplied on the second call with the terms from the first. That sequencing context is not derivable from the schema alone.

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 concrete verb and resource: give an ERC-8004 agentId on Base and get a trust verdict. It names the source of truth (the official Identity Registry at 0x8004A169...a432) and the exact return vocabulary (found/UNREGISTERED, risk flags, LOW/MEDIUM/HIGH), which separates it from neighboring tools like get_crypto_address_risk or token_security_check.

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 explicit procedural guidance: call once without x_payment to receive the x402 terms, then call again with the signed payment to get the result. It also shows the exact input shape {"agentId": 1}. It does not say when to prefer this over sibling trust/risk tools, so it stops short of full when-versus-alternative routing.

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