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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint false. The description adds valuable behavioral context: EIA as public-domain source, partial failure being non-fatal ('A source that fails is noted, not fatal'), and a disclaimer that it is informational, not trading advice. This goes beyond the annotations without contradicting them.

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 dense but efficient: three sentences covering what is returned, the use case, and failure/disclaimer behavior. The word 'premium' is mild marketing fluff, but the overall structure is front-loaded with the most important scoping information and does not waste sentences.

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?

With no output schema, the description carries the burden of explaining return payloads, and it does so explicitly: per benchmark it lists latest level and date, 1-year change, percentile, and trend direction. Combined with failure handling and source disclosure, an agent has enough to invoke and interpret the tool correctly.

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?

There is only one optional parameter, lookback_days, and its schema description already covers default, minimum, maximum, and purpose. The free-text description references 'trailing daily history' indirectly through 'recent history' but does not add meaning beyond the schema. Baseline 3 is appropriate given 100% schema coverage.

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 names a specific verb-resource pair ('One-call US energy market snapshot') and specifies the exact benchmarks covered: WTI crude, Brent crude, and Henry Hub natural gas. The use-case sentence ('what is oil/gas doing right now, and is it historically high or low') clarifies scope and differentiates it from more granular EIA sibling tools.

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 clearly states when to use the tool: for a single-call snapshot of current oil/gas prices with historical context. It does not explicitly list sibling alternatives or exclusion criteria, so it falls short of a perfect 5, but it gives strong contextual guidance for an agent.

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