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

Annotations already cover read-only, idempotent, open-world and non-destructive behavior. The description adds genuinely new context: results are ordered latest week first, carry the series name, and default to the US average — useful for interpreting answers rather than repeating annotations.

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 identity and data source, then example queries, then parameter guidance. Some phrases (fuel gasoline/diesel, area defaults to US) duplicate the schema, but there is no filler or tangents.

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 explaining return ordering, the series-name field, and the default 24-week window (in schema). An agent can call and interpret the result without further information.

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%, including defaults and enum meanings for fuel, grade and area, so the schema does the heavy lifting. The description only adds the "national headline figure" framing for regular grade and restates defaults already documented.

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: weekly national average retail pump price per gallon from EIA's Weekly Retail Gasoline and Diesel Prices survey. It clearly separates itself from the broader eia_petroleum/eia_series siblings by being the pump-price headline figure, and enumerates the covered queries.

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 query triggers ("current average US gas price", "how much is a gallon of gas") and explains how to select fuel/grade/area. It never states when NOT to use it or names an alternative sibling (e.g., eia_petroleum for spot prices), so it stops short of full routing guidance.

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