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

Annotations already establish that this is a read-only, idempotent, closed-world calculator, so the description does not need to repeat safety hints. The description adds useful behavioral context by listing the computed outputs, including expected string voltage, maximum string voltage, estimated active module count, and deviation percentage.

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 purpose is front-loaded and the description is compact overall. The long output enumeration is justified because there is no output schema, though the single dense sentence could be slightly easier to scan if split.

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?

All eight inputs are fully described in the schema, and because there is no output schema, the description appropriately explains the computed result fields. It does not cover assumptions or limitations of the calculation, but it is complete enough for an agent to invoke the calculator 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?

Schema description coverage is 100%, so every one of the eight parameters is already documented in the schema. The description does not add extra parameter-level semantics beyond what the schema provides, which is acceptable at the baseline for fully covered schemas.

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 verb and resource: calculating expected and maximum PV string open-circuit voltage and checking measurement deviation per DIN EN 62446. It is very clear about the calculation domain, but it does not explicitly differentiate itself from the many sibling tools, whose names are opaque identifiers.

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 a clear usage context by saying the calculation is for commissioning ('für die Inbetriebnahme'). It does not state when not to use the tool or name any alternative tool.

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