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

Goes well beyond readOnlyHint/openWorldHint by disclosing the paid-call mechanics: $0.003 USDC on Base per call via x402, unpaid calls return PaymentRequired, and x402-capable MCP clients pay automatically. It also flags the Arc native-USDC log handling quirk, which an agent could not infer from annotations or schema.

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 front-loaded sentences with almost no waste; purpose comes first, then usage, then cost. The mid-sentence parenthetical about Arc logs slightly interrupts the primary statement but earns its place by flagging a real quirk.

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?

Covers the full picture for a 6-parameter tool with no output schema: what is checked, what the response contains (verified flag, confirmations, matching transfers, reasons), the payment/auth requirement, and chain coverage. Nothing essential 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 0%, so the description carries the burden. It conveys the meaning of `to`, `chain`, and `minAmount` ('at least N USDC', 'Base or Arc'), and hints at confirmations in the return description, but `from`, the `tx` format, and the semantics/units of `minConfirmations` are never explained.

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?

Names a specific verb and resource with scope: verifies that a transaction paid at least N USDC to an address on Base or Arc. It is clearly distinguishable from siblings like explain_transaction and usdc_balances, which describe rather than verify payments.

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?

Explicitly states the intended use case: 'Use it to confirm a customer paid before delivering.' That gives a clear decision context, but it never names when NOT to use it or which sibling to reach for instead (e.g. explain_transaction for inspecting a tx without a payment check).

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