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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false, idempotentHint=true), and the description adds genuinely non-derivable context: the tool costs $0.01 USDC via x402, unlike the free router. It still omits what happens on a failed/blocked check and any latency or retry behavior, so it is not exhaustive.

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?

Very short and front-loads the trigger condition, cost, and fallback in that order. The opening is a sentence fragment with no subject or verb, which costs a little clarity but wastes no words.

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 cost plus sibling routing are covered. For a paid tool with 5 largely undocumented parameters, though, an agent still cannot tell how target, intent, or maxPriceUsd constrain the call — a real gap for something that charges per invocation.

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 description coverage is 0% across 5 parameters, so the description must carry the burden and largely does not. The only hint is that 'target' may be a resource, x402 endpoint, recipient, or Base address; intent, maxPriceUsd, expectedNetwork, and routingId are never explained or distinguished from each other.

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?

Combined with the title ('Preflight Security & Payment Risk Check'), the description makes clear this is a pre-payment risk gate, and it enumerates the concrete targets it covers (machine resource, x402 endpoint, recipient, Base address). However, the description itself is written as a timing clause rather than a verb+resource statement, so it never directly says what the tool returns (a risk verdict), leaning on the title to close the gap.

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?

Explicit trigger ('Before paying, transferring to, or interacting with an unfamiliar ... address'), explicit exclusion ('Do NOT use when: You only need market execution conditions or webpage extraction'), and an explicit alternative ('call signal_layer_router first for free'). This routes the agent across all four siblings without inference.

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