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

Goes well beyond the annotations: it discloses the pricing model ($0.003/call via x402 USDC or card key, first 25 free), that failed calls are free, that unknown/pending hashes cost nothing, and it proactively explains why readOnlyHint is false ('not marked read-only because each call is charged'). That last point converts a potentially confusing annotation into understood behavior.

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 purpose and return fields, then routing, then input/edge behavior, then commercial terms. Every sentence carries information an agent needs; nothing is redundant filler despite the density.

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, but the description compensates by enumerating the returned fields. Combined with the error behavior, pricing, and sibling routing, an agent has everything required to invoke this correctly on the first attempt.

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 description coverage is 100% and there is only one parameter, so the schema already carries the format definition. The description restates the 0x-prefixed 64-hex format and adds a concrete example hash, which is a mild invocation aid but largely duplicates structured data. Baseline 3 applies.

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 Arbitrum One transaction') and enumerates exactly what comes back: success/reverted status, gas used, effective gas price, fee paid in ETH, event log count, and any contract created. It also distinguishes itself from the sibling arb_tx by naming the fields that belong to that tool instead.

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?

Explicitly states when to use it ('Use to confirm a payment or call went through') and routes the agent elsewhere for a different need ('for sender, value and calldata use arb_tx'). It further defines edge-case behavior: a pending or unknown hash returns 404, uncharged, so the agent knows the failure mode without trial.

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