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

No annotations are provided, so the description carries the full burden. It discloses the tool's informational nature, what it covers (state programmes, payback arithmetic) and explicitly states what it does not cover ('No federal purchase premium — only the VAT exemption'). This gives a clear behavioral profile without contradictions.

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 compact and front-loaded, starting with the main topic and key details. It includes both German and English explanations, which adds a bit of redundancy but remains efficient. There is no wasted prose, and it effectively uses two sentences to convey substantial information.

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 tool with 4 optional parameters and no output schema, the description is highly complete: it explains the subject matter, the scope, exclusions, and hints at the calculation feature. Combined with the comprehensive schema, it gives the agent enough context to select and use the tool 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 coverage is 100%, with each parameter clearly described in the input schema. The description reinforces the payback context (e.g., ~100€ bonus) but does not add significant detail beyond the schema about individual parameters. Given high schema coverage, the baseline of 3 is appropriate.

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 ('Förderung... und wie ein Zuschuss die Amortisation verkürzt') and resource ('Balkonkraftwerk-/Speicher-Förderung in Deutschland'), clearly stating what the tool does: informs about state subsidies and calculates payback impact. It distinguishes itself from siblings by focusing on subsidies and payback arithmetic, which none of the sibling tools cover.

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?

Provides clear context by specifying the geographical scope (Germany), the types of subsidies (state programmes, ~100€ storage bonus, VAT exemption), and exclusions (no federal purchase premium). While not explicitly naming alternative tools, the scope is well-defined so an agent can infer when this tool is appropriate versus the sibling tools.

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