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

With only readOnlyHint and openWorldHint annotations, the description adds substantial behavioral context: perfect foresight, one full cycle per day, no grid fees or degradation, round-trip losses, and gross margin as an upper bound. It also discloses pricing and that failed calls are not charged, which is important operational behavior not present in annotations.

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 definition is front-loaded with the metric and scope, then gives assumptions and pricing in compact sentences. Despite being dense, every sentence adds useful selection or interpretation context.

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?

The description covers market, metric definition, assumptions, limitations, parameter options, and payment behavior, while the output schema can carry return-value details. It is complete enough for an agent to decide whether and how to call the tool.

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 description coverage is 100%, so the input schema already documents date, efficiency, and durationHours with defaults and ranges. The description reinforces the 1/2/4-hour options and 88% default efficiency, but adds little beyond the schema and does not add further syntax or constraints.

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 states a specific computed metric and market context: daily battery storage arbitrage margin on EPEX SPOT DE-LU hourly prices, including charging/discharging hours, spread, and gross margin per MW. It clearly distinguishes this derived BESS screening tool from raw power-price siblings.

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?

It gives clear usage context by calling the result an upper-bound screening number and explicitly not a trading result. It does not name a specific sibling alternative, such as the raw EPEX spot price tool, so it stops short of full when-to-use/when-not-to-use routing guidance.

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