chainpeek: was an x402 payment authorization used on-chain, and can it still settle

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

Goes well past the annotations (readOnly, openWorld, idempotent, non-destructive): it discloses price (USD 0.002), the free tier (10 chain reads per IP per UTC day), expected latency (1-3 s), that invalid input is a 422 and not charged, that 'used' also covers signer-cancelled authorizations, and an untrusted-data warning. That is the kind of context annotations cannot carry.

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?

Purpose and the alternative are front-loaded and each clause carries operational information (networks, error code, price, latency, rate limit). The block is dense and mixes boilerplate pricing/docs with semantics, but no sentence is pure filler.

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 an output schema present, return values need not be explained; the description still covers supported chains, error behavior, cost, latency, usage limits, the alternative tool and a prompt-injection caution. Nothing material to a correct invocation is missing.

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 100%, so the per-parameter baseline is 3, but the description adds combination semantics the schema only hints at: it spells out that the input is 'network' plus either 'x_payment' or 'authorizer' with 'nonce' and an optional 'token', clarifying the either/or usage pattern.

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 ('Check an x402 payment: was its USDC authorization used, can it still settle') and immediately distinguishes itself from the sibling test_x402_payment by naming it as the tool for making a real test payment. An agent can route correctly without opening any 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?

Gives the use case up front and an explicit alternative with its selecting condition ('To make a real test payment instead use test_x402_payment'). It also states the accepted networks and that any other network returns 422, which is a concrete when-it-works boundary.

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