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

Annotations already declare readOnlyHint=false and idempotentHint=false, and the description proactively explains why a read-shaped tool is not read-only (each call is charged), which prevents an agent from misreading the flag as destructive. It adds billing behavior ($0.003/call via x402 or card key, first 25 free), the failed-calls-are-free rule, and the 404/uncharged path for unknown hashes — real behavioral context beyond the annotations.

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 operation and return fields, then routing, then input format, then billing. Every sentence carries information, though the pricing sentence is dense and slightly crowds the functional content; still efficient overall.

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?

With no output schema, the description compensates by listing the receipt payload fields, and it covers the pricing/auth model an agent must know before calling a paid endpoint. For a one-parameter tool with rich annotations, nothing needed to call it correctly 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 coverage is 100%, so the 0x-prefixed 64-hex hash format is already documented; the description restates it and adds semantic value with a concrete example hash and the behavior of an unknown/pending hash. It stops short of adding anything further, but for a single-param tool that is ample.

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 precise verb+resource ('Get the receipt of a mined Base transaction') and enumerates the returned fields (status, gas used, effective gas price, fee in ETH, log count, contract created). It explicitly names the sibling it is not ('for sender, value and calldata use base_tx'), so an agent can separate it from base_tx without opening a schema.

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 a concrete use case ('confirm a payment or call went through'), names the alternative tool and what it covers instead, and specifies edge behavior for pending/unknown hashes (404, uncharged). Nothing about when to pick this over base_tx is left to inference.

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