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

No annotations are provided, so the description carries the full load, and it does disclose meaningful traits: official EIA daily spot figures rather than live futures, plus the 'data, not trading advice' limitation. It does not mention update cadence, latency, or authentication needs, but it is clearly a read-only reference endpoint. Useful behavioral context, short of exhaustive.

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 with the resource and source, then the returned fields, then two short caveats. Every sentence adds information, though the trailing 'Data, not trading advice' is more of a legal disclaimer than selection guidance and could be folded into the futures caveat. Tight for the amount of ground covered.

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 and no parameters, the description must convey what comes back, and it enumerates every metric (spot prices, four change windows, 52-week range/position, spread) and its provenance. Nothing further is needed for an agent to call this 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?

The tool takes zero parameters, so per the baseline there is nothing for the description to disambiguate. The description appropriately spends its words on the returned metrics instead, which is the right use of space for a parameterless endpoint.

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 the exact resource (WTI and Brent daily spot crude oil prices from EIA) and enumerates the derived fields returned: 1-day/1-week/1-month/1-year changes, 52-week range and position, and the Brent-WTI spread. The clause 'Official daily figures, not live futures quotes' cleanly separates it from nearby sibling tools such as oil_markets and oil_positioning. An agent knows precisely what it gets without opening the (empty) schema.

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?

Usage is only implied: the 'not live futures quotes' caveat steers the agent away when it wants intraday/futures data, and the enumerations imply when the tool is appropriate. There is no explicit when-to-use statement, no named alternative among the oil_* siblings, and no stated prerequisites or exclusions. Adequate but leaves routing to inference.

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