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

With annotations present, the description still adds substantial context beyond them: pending/unknown hash returns 404 and is uncharged, failed calls are free, pricing model, and an explicit explanation for why readOnlyHint=false ('not marked read-only because each call is charged'). This reconciles the annotation rather than contradicting it, which is high-value disclosure.

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?

Purpose and return fields are front-loaded, followed by usage routing, error behavior, and pricing. Content is dense and mostly earns its place, though the pricing/example tail adds length that is only marginally actionable for tool selection.

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?

No output schema exists, so the description correctly carries the return-value burden by enumerating receipt fields. Combined with error behavior (404), pricing, and the annotation rationale, an agent has everything needed to call and interpret it.

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 baseline would be 3, but the description adds format reinforcement ('0x-prefixed 64-hex hash') and a concrete example value, which meaningfully helps an agent construct a valid call beyond the schema's field description.

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+resource ('Get the receipt of a mined Optimism transaction') and enumerates exactly what the receipt contains: status, gas used, effective gas price, fee in ETH, event log count, and any contract created. It explicitly distinguishes itself from the sibling 'op_tx' for sender/value/calldata.

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?

Gives explicit when-to-use ('Use to confirm a payment or call went through') and names the alternative plus its scope ('for sender, value and calldata use op_tx'). This is a clear routing rule with no reliance on inference.

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