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

Beyond the readOnlyHint annotation, it discloses the null-return case when the node does not know the hash, the exact return field set, and the two-step x402 payment handshake. That is substantial behavioral context an agent needs to invoke it correctly.

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 purpose and payment flow are front-loaded, but the measured-output block dumps a full raw transaction including a long hex input blob, which is heavier than needed when a field list would suffice. Useful content, but not tight.

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 compensates by enumerating return fields and showing a concrete result, and it explains the payment flow. Minor gaps remain around error/rate-limit behavior, so it is strong but not fully complete.

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?

Only one parameter with 100% schema coverage, so the schema already documents 'transaction hash, 0x + 64 hex'. The description repeats the same format note without adding syntax or validation meaning beyond the schema.

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 ('Base on-chain read: a transaction by its hash') and names the underlying RPC method. The 'Base' qualifier plus the method name distinguishes it from the sibling eth_gettransactionbyhash on mainnet and from getblockbynumber/getlogs variants.

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 description gives invocation mechanics (call once without payment, then retry with the signed payment at _meta['x402/payment']), which is useful procedural guidance. However it never says when to prefer this tool over siblings such as the tx_receipt or bundle tools, leaving selection inference to the hash parameter.

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