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

With no annotations, the description carries the full burden. It discloses several behavioral traits: performs a real on-chain lookup, decodes specific USDC Transfer event fields, returns a verification_id for later re-fetch, and costs $0.01 via x402. It does not detail edge cases like invalid tx_hash or network failures, but covers core behavior well.

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?

Two sentences, front-loaded with the main purpose. The first sentence efficiently lists key features in a compact list, and the second states pricing. No redundant text.

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?

Despite lacking an output schema, it enumerates the expected return data (receipt lookup, decoded events, status, confirmations, verification_id). It also notes cost. Given the modest parameter set, the description is sufficiently complete for an agent to decide and invoke.

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 already describes both parameters (tx_hash format and chain_id default/limitation) with 100% coverage. The description adds context about the purpose (verifying x402 settlement) but does not add new parameter-level details beyond what the schema provides.

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?

Begins with a specific verb+resource: 'Verify an x402 settlement actually landed on Base mainnet.' It clearly distinguishes itself from sibling tools by enumerating unique capabilities: real JSON-RPC receipt lookup, decoded USDC Transfer events, success/reverted status, confirmation count, and stored verification_id.

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?

Provides clear context: it is for verifying an x402 settlement on Base mainnet after the fact. The mention of 'real JSON-RPC receipt lookup' implies a more thorough check than simpler status tools, but it does not explicitly name alternatives or state when not to use it.

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