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

With no annotations, the description carries the full burden and does so: it discloses the response contents, that it merges two RPC calls into one, that no API key/account is needed, and the exact cost ($0.005/call over x402 USDC). Pricing and auth requirements are behavioral facts an agent cannot infer from the schema.

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 use case, then exclusions, then behavior, then cost — a logical order with no filler. It is dense and slightly overpacked into a few long clauses, but every sentence contributes information.

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, and the description compensates by enumerating the returned fields and combined-call semantics. With no annotations, it still covers auth, pricing, and scope, leaving nothing an agent needs to call it correctly.

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 both parameters (hash, chain) are documented there. The description adds no format, syntax, or chain-default guidance beyond the schema, so this sits at the baseline for full schema coverage.

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: fetches a transaction by hash merged with its receipt in one call, listing exactly which fields (sender, recipient, value, gas used, success/revert, block). It explicitly names the sibling tools (evm_receipt, evm_estimate_gas) whose territory it does not cover, so the agent can distinguish it without opening schemas.

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 an explicit trigger scenario ("agent has sent a transaction and must decide what to do next"), plus two explicit exclusions with the alternative to use instead: evm_receipt for mined-or-not checks and evm_estimate_gas for pre-signing judgement. Nothing is left to inference.

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