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

Goes well beyond the annotations by disclosing pricing ($0.002 USDC on Base), the no-charge-on-not-found policy, the two-step x402 payment handshake (MCP PaymentRequired then signed PaymentPayload in params._meta), the legacy _x402_payment fallback, and that signing happens in the caller's wallet. This also explains why readOnlyHint=false despite the operation being a verification call.

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?

Front-loaded with the capability and return payload before the commercial/payment details; every sentence is informational. Minor redundancy: the $0.002 USDC on Base price is stated twice, once inline and once in the bracketed paid-flow block.

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 paid, single-purpose verification tool with an output schema, the description covers inputs, outputs, pricing, failure semantics, network scope, and the payment handshake. An agent has everything needed to invoke it correctly on the first call and to interpret a PaymentRequired response.

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 baseline is 3; the description adds value by framing expected_to and expected_amount as producing 'match flags' against the decoded USDC transfer, and by explaining the _x402_payment retry mechanics. It does not restate formats (atomic units, address patterns), which the schema already covers.

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?

Opens with a specific verb+resource ('Verify Base transaction by hash') and enumerates exactly what is returned: status, block, timestamp, confirmations, decoded USDC/ERC-20 transfers, EIP-3009 authorizations, and match flags. This clearly separates it from siblings like ontario_base-balances or ontario_base-gas.

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 names the use case ('so an x402 payment receipt or PAYMENT-RESPONSE can be checked as settled') and states prerequisites: required hash, Base mainnet only, no account or API key. It does not name an alternative sibling for non-payment transaction inspection, so it falls short of a 5.

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