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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint, and non-destructive, so safety is covered. The description adds the useful fact that source is EIA and the cadence per series (daily/monthly/weekly), which is context annotations don't carry, but says nothing about coverage windows, latency, or units.

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-loaded source and resource, then a tight enumerated list of options with the default at the end. One redundancy: the word 'spot' and the default are both stated, and 'Series options' duplicates the schema enum, but overall efficient.

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 4-param read-only data tool with full schema coverage and annotations, the description is adequate. It is missing units, geography caveats, and whether multiple series can be requested together, small but real gaps for a data-query tool with no output schema.

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 series enum is fully documented in the schema, so the description largely restates it. The per-series cadence hints (daily/monthly/weekly) add modest value for choosing start/end formats, but nothing about limits or date semantics beyond 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-like scope (US natural gas data from EIA) plus the resource and enumerates the four series with definitions, which no sibling schema exposes. Distinguishable from eia_electricity_state, eia_oil_supply, eia_series_lookup at a glance.

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?

Provides implicit selection guidance by defining each series option, so an agent can pick the right cadence. But it never names alternatives (e.g. eia_series_lookup for non-priced series) or states when not to use this tool. Minimum-viable usage guidance.

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