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

Adds real context beyond annotations: 404 for unknown hash with no charge, per-call pricing ($0.01, first 25 free, failed calls free), and that repeats are not free — which explains idempotentHint=false well. The explanation of what the call costs and does-nothing-to-state is useful, though it could be tightened slightly.

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-loads the operation and scoping/alternatives before pricing details, and every sentence carries information. The final sentence is dense (read-only + per-call charge combined) but each 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 enumerates the returned fields and states the 404-miss behavior. Combined with annotations covering safety and a single fully-documented parameter, an agent has everything needed 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 coverage is 100%, so the format is already documented, but the description reinforces the 0x-prefixed 64-hex requirement and provides a concrete example hash, plus the behavior for an unknown hash. This adds modest value over 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 ("Look up") and resource ("Scroll transaction by hash") and enumerates the returned fields (sender, recipient, value in ETH, nonce, gas limit, selector, block). It explicitly distinguishes itself from scroll_receipt and scroll_logs, so an agent can route 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 explicit when-to-use ("see what was sent or whether it exists") and names the two alternatives with their selecting conditions: scroll_receipt for success/failure and fees, scroll_logs for emitted events. 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.