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

Annotations already declare readOnly/destructive/openWorld, and the description usefully adds the cost model ('$0.002 USDC on Base') plus the risk categories examined. However, it omits how payment is authorized, whether calling it requires an x402 wallet, or any rate/latency behavior — meaningful gaps for a paid, open-world tool.

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 tight sentences with zero filler: the audit scope is front-loaded and the cost is stated once. Every clause carries information an agent can act on.

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?

An output schema exists so return values need no explanation, and annotations carry the safety profile. The remaining gap is the payment/auth mechanics behind the stated price, which is minor given the otherwise complete framing.

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 parameter with 100% schema coverage, so the schema already documents 'x402 URL to audit'. The description adds no format, validation, or example detail beyond what the schema provides, making the baseline 3 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?

Specific verb + resource ('Audits any target x402 endpoint') plus the exact artifacts inspected (402 challenge, payTo wallet, amount, schema). It distinguishes itself by domain (x402 endpoint) but never names or contrasts with the security_* siblings, so differentiation is implicit.

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?

No when-to-use guidance, no prerequisites, and no exclusions relative to security_url_threat_check or security_evm_calldata_firewall. The agent must infer that this is a pre-payment safety check from the phrase 'hijack/overcharge risks' alone.

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