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

With no annotations, the description carries the full burden and does disclose two important traits: the underlying RPC method (eth_getTransactionByHash) and the paid-access model ($0.005 per call over x402/USDC), which an agent otherwise could not infer. It omits error behavior for unknown hashes and any rate/latency context, so it is not fully transparent.

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?

Three short, front-loaded sentences with zero filler: what it returns, why to prefer it, how it is executed and billed. Every clause earns its place.

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 usefully enumerates the returned fields, and it discloses the payment mechanism an agent must know before calling. It omits chain defaulting and failure behavior, but the core calling information is present.

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 both 'hash' and 'chain' are already documented in the schema; the description only reinforces 'by hash' and adds nothing about the chain parameter (default value, supported chain syntax). Baseline 3 applies when the schema does the heavy lifting.

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+resource ('Full transaction details by hash') and enumerates the returned fields (from, to, value, gas used, status, block), which crisply separates it from the sibling evm_receipt and evm_call tools that return only partial data.

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?

The phrase 'One call instead of two' tells the agent this replaces the transaction+receipt pattern, implicitly steering away from evm_receipt for this use case. It stops short of explicitly naming the alternatives or stating when NOT to use it (e.g. when only the receipt is needed).

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