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

Annotations already cover read-only and non-destructive nature, but the description adds what they cannot: per-call pricing ($0.01 via x402 USDC or card key, first 25 free), failed calls free, and the crucial clarification that a repeat call is charged again — which explains the otherwise puzzling idempotentHint=false on a pure read. The 404-on-pending behavior clarifies failure semantics.

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 usage routing, then input format, then pricing — a sensible order. The inline example hash is long and the pricing sentence is dense, but each carries actionable information rather than filler.

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?

There is no output schema, so the description compensates by enumerating every meaningful receipt field. Combined with the payment model, error semantics, and input format, an agent has everything needed to call it correctly and predict the cost.

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 parameter is already documented; the description reinforces the 0x-prefixed 64-hex format and supplies a concrete example hash an agent can pattern-match against. It adds value but stops short of describing any transformation or normalization the server performs on the input.

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 the specific operation (eth_getTransactionReceipt on Scroll) and enumerates exactly what the receipt yields: status, gas used, effective gas price, fee in ETH, log count, contract created. It also explicitly separates itself from the sibling scroll_tx by naming what that tool covers (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?

'Use to confirm a payment or call went through' gives the triggering condition, and 'for sender, value and calldata use scroll_tx' names the alternative and the case that selects it. The pending/unknown 404 behavior further defines the boundary of what this tool can answer.

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