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

Goes well beyond the annotations: discloses the 404-without-charge behavior for pending/unknown hashes, that failed calls are free, the pricing model (x402 USDC / card key, first 25 free), and why readOnlyHint is false (each call is charged). This is exactly the extra context annotations cannot express.

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-loads the resource and return fields, then the when-to-use routing, then billing semantics. Dense but every sentence carries information; the pricing block is verbose but operationally necessary for a paid tool.

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 lists what the receipt contains, covers the error path and billing, and gives a callable example. Nothing an agent needs to invoke this 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 baseline is 3, but the description adds a concrete example hash and reinforces the required 0x-prefixed 64-hex format plus the runtime behavior for a bad/unknown hash. It slightly exceeds what the schema alone conveys.

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?

Names a specific verb and resource ('Get the receipt of a mined Ethereum transaction') and enumerates the returned fields (status, gas used, effective gas price, fee, log count, contract created). It explicitly distinguishes itself from the sibling eth_tx, so an agent can route correctly without opening either 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?

States the use case ('confirm a payment or call went through') and names the alternative with its selection condition ('for sender, value and calldata use eth_tx'). Pending/unknown hashes are covered as an explicit failure mode.

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