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

With no annotations, the description carries the full burden and it does well: it discloses that the tool is paid ($0.05 USDC via x402), requires EIP-3009 on Base, follows a two-phase challenge/response flow, and that the first call returns a payment challenge while the second requires x_payment and returns the report. This explains the interaction model and cost, which is crucial for an agent to invoke it correctly.

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?

Two dense sentences that front-load the key facts: paid status, scope, cost, and two-phase behavior. No filler; every clause adds a decision-relevant detail (chains, flags, payment mechanism, call sequence). The structure is clear despite the parenthetical cost detail.

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 paid, two-phase tool with no output schema and no annotations, the description is largely complete: it covers the payment prerequisite, the call sequence, and the expected report. However, it does not describe the report's structure or fields, nor error/failure behavior if payment is not provided, which an agent might need for robust handling.

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. The description adds workflow context: it explains that x_payment is only used in the second call and ties it to the payment challenge from the first call, and it specifies the payment channel (x402, EIP-3009 on Base). This clarifies the parameter's role beyond the schema's string description.

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: 'deep scan' for an address, with clear scope: 'full verification across ALL FIVE chains (Base, Ethereum, Arbitrum, Optimism, Polygon)' and specific detection features ('wrong-network detection and USDC/USDT token-mismatch flags'). The 'TWO-PHASE like check_address' phrase anchors it relative to siblings without confusing it with them, because the multi-chain and paid attributes distinguish it.

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?

The description implies the use case: when the user needs comprehensive multi-chain verification and accepts the $0.05 USDC cost. It explicitly describes the two-phase protocol so an agent knows to call twice, but it does not state when to choose check_address or validate_address instead, nor when not to use this paid tool.

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