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

With no annotations, the description carries the full burden, and it does disclose the meaningful trait: this is a read-only retrieval bounded to a 24-hour horizon that also computes a cheapest window. It omits any note on auth requirements, refresh/prediction cadence, or behavior at the boundary, but the operation is low-risk and self-evident from 'Get'.

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?

Two sentences, zero filler, with the resource and horizon front-loaded and usage triggers trailing. Every 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?

There is no output schema, so the description must carry return semantics, and it does characterize the payload as hourly forecast data plus a predicted cheapest window. It leaves the exact shape of the hourly values unspecified, but for a simple read-only forecast tool this is nearly 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?

Schema coverage is 100% and the single `hours` parameter already documents its 1-24 range and default of 12. The description only restates the 24-hour ceiling already implied by the schema, adding no syntax or interpretation value beyond it. Baseline 3 applies when the schema does the heavy lifting.

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+resource ('Get the forward-looking hourly Ethereum gas forecast') with an explicit horizon (up to 24 hours) and return scope ('predicted cheapest window'). The 'forward-looking' framing cleanly separates it from get_current_gas and get_gas_history without needing to name them.

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 concrete user-intent triggers ('when will gas be cheaper', 'should I wait until tomorrow', planning a transaction), which is strong context. It stops short of naming the overlapping sibling best_time_to_transact or stating when this forecast is the wrong choice, so it is clear but not fully disambiguating.

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