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

With no annotations, the description carries the full burden. It discloses the internal behavior: 'decodes every USDC Transfer log in the receipt (from, to, amount)' and the binary outcome 'settled true/false'. It also transparently states the cost ($0.004/call). Missing edge cases like what happens for non-USDC or non-existent transactions, but the provided detail is above average.

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?

The description is a single well-structured sentence that front-loads the core purpose ('Verify a Base mainnet tx hash'), then elaborates with mechanism, use case, and cost. Every phrase earns its place; no filler or redundancy.

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 one-parameter tool with no output schema, the description is complete: it explains what the tool checks, how it checks it, what it returns (true/false), when to use it, and the cost. The sibling context shows it's well-positioned among related tools, and the description fully satisfies the need.

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?

The schema already fully describes the single 'tx' parameter with pattern and description, giving 100% coverage. The description adds valuable semantic context by specifying this is a 'Base mainnet tx hash' and that it's specifically for USDC, which is not in the schema. This elevates it above the baseline.

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?

The description clearly states the tool's specific verb and resource: 'Verify a Base mainnet tx hash actually moved USDC'. It goes further by explaining it decodes every USDC Transfer log and answers settled true/false, which sharply distinguishes it from sibling tools like base_tx_status or base_usdc_balance.

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?

The description provides clear context: 'the check an x402 seller runs before trusting a payment reference'. This tells the agent exactly when to use it. However, it doesn't explicitly mention alternatives or when not to use it, such as when a simpler tx status check would suffice.

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