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

With no annotations, the description carries the full burden and does well: it discloses the payout model ($0.005 per call, x402/USDC), the absence of auth ('No API key, no account'), and the key pending-state semantics ('found: false means it is not mined yet'). It stops short of stating how the optional chain parameter defaults or how reverts are represented in the payload, which is the remaining behavioral gap.

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?

The triggering condition is front-loaded, followed by return contents, the not-mined interpretation, the sibling exclusion, and the cost/auth terms. Every sentence maps to a distinct decision the caller must make; nothing is padding.

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 and no annotations, the description does the heavy lifting: it enumerates the return fields an agent needs and explains the pending-state signal. Slightly short of complete because the chain parameter's default (when omitted) and the exact revert representation are unaddressed.

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% and both parameters (hash, chain) are already documented with accepted values, so the description adds no syntax or format detail beyond the schema. Baseline 3 is appropriate; the description's value lies in behavior, not parameters.

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 and resource ('the receipt by hash') and enumerates exactly what it returns: success/revert, gas used, fee paid in ether, log count. It explicitly carves out the sibling evm_tx case ('transaction's own fields like value or recipient'), so the agent can separate the two 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?

Gives a concrete triggering situation ('an agent is waiting on a transaction and has to answer did it work, and what did it cost') and a concrete exclusion with the alternative named ('Do not use for ... /v1/evm/tx returns both merged'). Both the when and the when-not are stated.

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