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

readOnlyHint=true already tells the agent this is a safe read, and the description is consistent with that. It adds useful domain context (pricing is USDC on Solana, and /swap-guard also takes Base), but does not explain that consuming the listed endpoints requires an x402 payment flow, nor anything about rate limits or response shape.

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 short sentences, front-loaded with what is listed and followed by the audience qualifier and the payment-currency caveat. Nothing is wasted or padded.

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 must hint at returns, and 'with prices and URLs' does that. For a zero-param, read-only listing tool this is close to complete, though it could say more about the payment step needed to act on the results.

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?

The tool takes zero parameters, so there is nothing for the description to disambiguate; the baseline of 4 applies. No parameter-level detail is warranted or missing.

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 ('List Axiom's paid x402 endpoints') and enumerates what each entry carries (prices and URLs), which is more than the bare name conveys. It does not name or contrast itself with the sibling preview tools, so it falls short of full sibling differentiation.

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 clause 'For agents that can pay via x402' gives a target audience, implying when the tool is relevant, but it never states when to use it over swap_guard_preview or token_risk_preview, nor any exclusion or prerequisite flow.

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