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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), so the description's job is to add calculation behavior — which it does by naming the factors used (autonomy days, depth of discharge) and the outputs produced. It stops short of stating assumptions or caveats for edge cases, keeping it below a 5.

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?

Three tight sentences: purpose first, then the calculation factors, then the return values. No filler, though the middle sentence largely echoes parameter names already documented in the schema.

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 full schema coverage and no output schema, the description supplies enough to call the tool correctly and even summarizes the three return values. Missing is any mention of the battery-config sibling or of assumptions when mixing battery types.

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 coverage is 100%, with every parameter individually documented including defaults and example values, so the baseline is 3. The description restates days-of-autonomy and depth-of-discharge conceptually but adds no syntax or unit detail beyond the schema.

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?

States a specific verb and resource ('Calculate the recommended battery bank size') and names the inputs it depends on. It does not, however, distinguish itself from the closely-named sibling calculate_battery_config, leaving an agent to guess which sizing tool to pick.

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 implies the upstream dependency on daily energy consumption (the schema explicitly points to calculate_power_budget), giving some context for when the tool fits a workflow. It offers no explicit when-not guidance and never mentions the alternative sibling calculate_battery_config.

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