check_payment_readiness

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

With no annotations, the description carries the full burden and mostly succeeds: it marks the tool as free, describes a read-only investigation (reads terms, calls the named facilitator's /supported and /verify, prices against live Base gas and Chainlink ETH/USD, optionally reads on-chain balance), which tells an agent this performs live network calls but does not sign or spend. It loses a point because the final 'Returns v' is truncated, leaving the response shape and any failure semantics undisclosed.

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?

The '[FREE]' prefix and the 'RIGHT NOW, before you sign anything' framing front-load the decision-relevant facts, and the contrast with the sibling tool arrives in the second sentence. The long middle sentence is dense but every clause describes a distinct step of the check; the only defect is the truncated trailing sentence.

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 multi-step buyer-side handshake check with no output schema and no annotations, the description does substantial work by enumerating each internal step and naming the external dependencies (facilitator, gas oracle, Chainlink feed). The truncated 'Returns v' leaves the return contract unspecified, which is the one meaningful gap given no output schema exists to fall back on.

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%, so the description must compensate for all three parameters. It explains 'wallet' clearly (only when supplied does it read on-chain balance) and implies 'endpoint_url' is the endpoint under inspection, but 'method' is never mentioned in the description and its role is left entirely to the bare schema default of GET.

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?

The description opens with a specific verb and outcome ('Find out whether you can complete a payment to an x402 endpoint RIGHT NOW') and immediately distinguishes itself from the nearest sibling: it is the buyer-side check, whereas check_x402_endpoint grades the seller's 402. An agent can select between the two without opening either schema.

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?

It gives an explicit condition for use ('before you sign anything') and names the alternative tool plus the different question each answers. It falls short of 5 because it does not address other plausibly overlapping siblings such as preflight_check, safe_preflight_check, or check_facilitator_liveness, nor does it state when this check is unnecessary.

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