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

With no annotations, the description must carry the behavioral burden. It discloses the cost ($0.005), the enrichment source (openchain signature DB), and what the response contains. However, it is silent on failure behavior for unknown or non-Arbitrum hashes, latency, and whether decoding is best-effort when no signature match exists.

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?

A single front-loaded sentence that enumerates outputs and ends with the price. Every clause adds usable information; nothing is repeated from structured fields.

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?

There is no output schema, so the description is the only source of return-value information. It names the key return facets, which is enough for selection, but it omits the response shape and edge-case behavior for tools that return decoded calldata and token transfer lists.

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?

There is one parameter at 0% schema description coverage, so the description should compensate. It implies the input is a transaction hash but adds no format, length, or chain-relevance detail beyond the schema's regex pattern.

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?

The description pairs a specific verb ("Explain") with a specific resource ("a Arbitrum transaction") and enumerates the returned facets: status, fee, decoded method + args, and ERC-20 transfers. The chain qualifier cleanly separates it from the avalanche_/base_/bsc_/ethereum_tx_explain siblings, so an agent can pick the right chain variant without opening a 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?

This description provides no clear usage guidance. There is no indication of when to prefer this tool over calldata_decode, address_inspect, or contract_risk, nor any prerequisites such as needing a valid Arbitrum transaction hash. The only guidance is implied by the tool's name.

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