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

Annotations already establish readOnly/idempotent/closed-world, so the safety profile is covered. The description adds value by naming the returned quantities, but it never explains the relationship between them (P_AC = P_DC/k, S_AC = P_AC/cos phi) or what the region switch actually changes, so behavioural insight is partial.

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?

Two sentences, front-loaded with the computation and followed by the result list; the second 'Ergebnis' clause is slightly redundant but the output enumeration earns its place given there is no output 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 no output schema, listing P_DC/P_AC/S_AC is necessary and present. However, the region parameter (DE vs CH standards) is never mentioned, nor are any assumptions, rounding, or default behaviour, leaving a real gap for a calculation tool whose outputs feed downstream sizing decisions.

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% and every property carries a title, range and default, so the schema does the heavy lifting. The description only restates n_module, p_modul, k_dc_ac and cos_phi and omits the region parameter entirely, adding nothing beyond the schema. Baseline 3 applies.

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?

Specific verb and resource: computes inverter power from module count, module power and DC/AC ratio, and names the three returned quantities. It cannot be differentiated from the opaque sibling names (bot_009, bot_040, ...), so it stops short of a 5.

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 input-to-output flow implies when the tool applies (sizing an inverter for a given array), but there is no explicit when-to-use/when-not-to-use statement or comparison to any alternative. For a self-contained calculator this is 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.