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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safe-read profile is covered. The description adds a genuinely useful non-structural fact – a $0.004 USDC per-call x402 cost – but says nothing about pagination, units, or how far back data goes, which matters for a series tool with no output schema.

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, front-loaded with the data scope and ending with the cost, with no filler. The indicator listing is dense but each item earns its place; only minor tightening is possible.

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, no-output-schema data tool the safety and cost picture is adequate, and the covered series are named. Gaps remain: the 'points' parameter is unexplained, and there is no differentiation from the electricity/gas/mix siblings an agent is likely weighing.

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 67%, near the baseline threshold. The description maps 'indicator' values to the covered series and ties 'state' to residential electricity, but 'points' (presumably history depth) is undocumented in both the description and the schema, leaving one parameter opaque.

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 (retrieves) and resource (US energy prices from the EIA) and enumerates the covered series: gasoline, diesel, WTI, Henry Hub gas, crude inventories, and state electricity prices. It is clear what the tool returns, but it does not distinguish itself from overlapping siblings like energy_electricity_prices, energy_gas_prices, energy_mix, or energy_forecast.

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 description never states when to use this tool versus its numerous siblings, several of which cover the exact same series (electricity prices, gas prices). No prerequisites, exclusions, or alternatives are given; the agent must infer routing on its own.

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