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

The description details the calculation components (25% rate above allowance, 5.5% Soli, no Freigrenze, church tax reduced rate), going well beyond the annotation hints (readOnly, idempotent). This provides a clear behavioral model of how the tax is computed, including the treatment of church tax.

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 at two sentences, front-loading the tax type and scope before diving into rates. Every sentence contributes substantive tax rule information without redundancy or filler.

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?

Given the complexity of German capital gains tax and the presence of a full output schema and annotations, the description provides sufficient context on the tax rules, rates, allowance, and church tax effects. It explains the core calculation intent without needing to describe return values.

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?

All five parameters are already fully described in the input schema (100% coverage), so the description adds little parameter-specific meaning. The mention of the Sparerpauschbetrag and church tax rates aligns with parameters, but the schema already carries this information.

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 clearly identifies the tool as computing Germany's flat tax on capital income (Abgeltungsteuer), citing the legal provision (§32d EStG) and specifying the applicable tax years (2023-2026) and the built-in Sparerpauschbetrag. This distinguishes it from other German tax tools like de-net-salary or tax-from-brackets.

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 use for German capital gains tax calculations but does not explicitly state when to use this tool versus alternatives like de-net-salary or tax-from-brackets. It only constrains applicability to tax years 2023-2026, leaving usage guidance implicit.

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