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

Annotations already establish that this is read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds the notion that the result is an estimate, but it does not disclose output format, calculation assumptions, or limitations beyond that.

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 a single compact sentence with no filler. It front-loads the operation and resource, then states the input sources, making it easy for an agent to parse quickly.

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 simple, read-only three-parameter calculation, the description is sufficient: an agent can infer to pass power_kw, hours, and price_per_kwh and expect an energy and cost result. There is no output schema, but the description names the outputs at a high level, which is adequate for this tool's simplicity.

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 0%, so the description must compensate. It maps 'demand' to power_kw, 'runtime' to hours, and 'tariff' to price_per_kwh, which adds meaning, but it does not explain units, ranges, or the exact relationship between inputs and outputs. The parameter names themselves remain the main semantic source.

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 uses a specific verb ('estimate') and a specific resource ('operating energy and cost') with source inputs ('demand, runtime and tariff'). This clearly distinguishes it from sibling heat-loss, capacity, and equipment-offer tools, even without naming a sibling.

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 phrase 'from demand, runtime and tariff' implies the intended use case: when the agent has power, hours, and price per kWh available and wants an energy/cost estimate. However, there is no explicit guidance about when not to use it or how it compares to siblings like compare_heating_options or solve_heating_task.

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