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

With no annotations, the description carries the full burden and discharges it well: it discloses per-chain proof mechanisms, the reclaimable challenge window on Base, that results include re-checkable evidence and an Ed25519-signed receipt, that it will never answer not_paid for a still-pending payment, and that it abstains when proof is incomplete. Pricing ($0.02 / $0.002, free on repeat claims) and the x402 payment requirement are also surfaced.

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?

One dense paragraph, but front-loaded with the core question and tightly ordered: trust model, proof mechanics, return contents, semantics, cost, optional params. Nearly every clause carries information; it is long only because the tool is genuinely complex.

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 10-parameter tool with no output schema and no annotations, the description fills the gaps: it names what is returned (proof level, challenge window, evidence, signed receipt), the cost model, and the abstention/pending semantics. Nothing an agent needs to decide and invoke correctly appears 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 coverage is 100%, so the schema already documents every parameter, setting the baseline at 3. The description adds only marginal value here (default token USDC, that requiredLevel is optional and drives a 'releasable' answer, callbackUrl fires on the three specified events), essentially paraphrasing what the schema already states.

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 (verify an on-chain payment) with the distinctive qualifier 'without trusting any RPC', and frames the exact question it answers (did this tx transfer at least this amount to this payee). An agent can separate it from try_verify_payment or verify_payments_batch by the trust model and proof narrative alone.

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 context is implied rather than stated: 'asking again about the same claim costs nothing' hints at idempotent re-checking, and the pending/abstain rules explain when an answer is meaningful. But it never names when to prefer this over the sibling try_verify_payment (likely a dry run) or verify_payments_batch, leaving the agent to infer the routing.

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