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

Annotations only cover safety flags (readOnlyHint=false, destructiveHint=false, openWorldHint=true), and the description adds real substance beyond them: the board performs a single no-payment probe, the 402 payTo must match the registered pay_to on Base USDC, the listing is created pre-verified, and it is non-custodial. It stops short of describing idempotency or failure behavior when verification fails, which is the one notable gap.

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?

Three tight sentences with the core action front-loaded, followed by the verification rule and the auth/non-custodial notes. Every sentence carries information, though the probe and payTo requirement are packed densely enough to slow a first read.

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 mutation tool with no output schema and only safety-oriented annotations, the description covers the important behavioral facts: auth requirement, verification semantics, and non-custodial guarantee. It is somewhat incomplete on the non-required metadata parameters and on what happens on verification failure.

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 4 parameters, so the description must carry the burden and does not. Only 'url' is loosely implied by 'your paid x402 endpoint'; title, category, and description are never mentioned, and even url's expected format is not clarified.

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 your paid x402 endpoint') and clarifies the mechanism ('in one call', x402-verified listing). It distinguishes itself functionally from the generic create_listing sibling through the x402 verification flow, but never names that sibling explicitly, so the differentiation is inferred rather than stated.

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?

Usage is implied by 'your paid x402 endpoint' and the verification requirement, which tells the agent this is only for endpoints exposing a 402 payTo. However, there is no explicit when-to-use versus create_listing guidance, no prerequisites section, and no exclusions, so the agent must infer the boundary.

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