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

Annotations already declare read-only, idempotent, non-destructive, open-world behavior, so the safety profile is covered structurally. The description adds real context beyond that: it is advisory/derived, based on 'current and recent fee conditions', and includes a savings estimate. It stops short of describing how the recommendation is derived or its confidence, which keeps it out of 5 territory.

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 tight sentences: purpose, scope, and disambiguation, front-loaded so the core purpose lands first. The negative enumeration is compact and each clause carries distinct routing value; no filler.

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?

For a read-only advisory tool with an output schema (so return values need not be explained) and annotations covering the safety profile, the description supplies everything an agent needs: what it does, when to use it, and which siblings to prefer instead.

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 a single optional 'chain' parameter with 100% schema description coverage, so the schema fully documents it (including the base default). The description adds no meaning about the parameter, which is acceptable given full coverage — the baseline 3 applies.

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 states a specific resource and verb ('Gas price optimization advisor') plus the concrete action ('analyzes recent block patterns to recommend the best time to transact'). It explicitly names the sibling tools it is not (gas.tracker, gas.history, gas.predict), so an agent can distinguish it without opening any 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?

It gives an explicit trigger phrase ('Use this for "when should I submit?"') and enumerates the three sibling tools whose use cases it does NOT cover, with the reason for each (raw quote, history response, standalone forecast). 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.