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

Annotations already declare readOnlyHint=true and destructiveHint=false, and the description adds meaningful context by noting the dependency on 'when EIA API is configured' and naming the source as 'US Energy Information Administration.' It also gives example return values, though it doesn't specify frequency or data vintage beyond the example.

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 three sentences: a usage statement, a returns statement, and an example with source attribution. It is efficient and front-loaded, though the example could be trimmed without losing much value; still, the extra context supports the use case.

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 zero-parameter snapshot tool with no output schema, the description covers purpose, exact data returned, example values, API dependency, and source. It is mostly complete, though it doesn't mention whether prices are delayed or real-time, or how often they update.

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?

The tool has zero parameters, so the baseline is 4. The description adds no parameter-related information, but none is needed since the input schema is complete and empty.

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 states the tool's purpose: 'Use when current energy price data is needed' and specifies the exact output: 'Returns WTI crude and natural gas spot prices'. This distinguishes it from sibling benchmark tools by focusing specifically on energy spot prices, with a concrete example in the description.

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 explicit context for when to use: 'for a commodity brief, input cost analysis, or energy sector context in a CFO or investment brief.' It does not explicitly exclude alternatives, but the context is clear enough to guide selection among the many sibling benchmark tools.

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