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

The annotations already declare the tool read-only, idempotent, and non-destructive, so the description only needs to add context beyond that. It adds useful cadence and default-series behavior, but it does not disclose the output shape, ordering, date-bound interpretation, or potential quirks across different series cadences.

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?

The description is a single compact sentence that front-loads the resource and packs the series options, cadences, and default without redundancy. Every clause contributes meaningful information.

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 simple, read-only data retrieval tool with fully documented parameters and safe annotations, the description covers the important selection dimension and default behavior. It omits output format or units, but the schema and annotations carry enough weight that the missing output details are a minor gap rather than a blocking one.

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 baseline is 3. The description adds value by expanding the series enum with concrete meanings and cadences ('spot' = Henry Hub daily, 'residential' = monthly retail) and reinforces the default value, which goes beyond the schema's bare parameter descriptions.

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 clearly identifies the resource as US natural gas data from EIA and enumerates the available series with their cadences, which distinguishes it from sibling EIA tools focused on electricity, gasoline, oil, or renewables. It stops short of a 5 because it uses the noun phrase 'data' rather than a specific verb like 'retrieve' or 'fetch'.

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?

The intended use is implied by the commodity focus and series options, but the description does not explicitly state when to choose this tool over sibling EIA data tools or when to use an alternative. There is no exclusions or routing guidance, so the agent must infer usage from the domain.

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