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

Annotations already declare readOnlyHint=true and idempotentHint=true. The description adds valuable behavioral context: income tax and Soli are amounts, church tax is a percent of income tax, and social rates/ceilings are explicit inputs. It also clarifies the manual model. No contradiction with annotations.

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 only two sentences. The first sentence states the purpose, and the second covers the manual-input requirement, the input types, and unit consistency. Every word earns its place, with no redundancy.

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 10-parameter tool, the description adequately explains the external figures needed, the relationships among inputs, and the unit consistency requirement. The output schema covers the return structure, so the description doesn't need to detail outputs. It could mention calculation order or edge cases, but the provided context is sufficient for an agent to select and invoke 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%, so each parameter is already described. The description adds meaning by grouping 'the four employee social rates and the two contribution ceilings' and clarifying the type relationships (e.g., church tax as percent of income tax, income tax as amount). This goes beyond the individual parameter descriptions.

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 'German net (Netto) salary from gross (Brutto)' with a specific verb and resource, and the title adds 'manual figures,' which distinguishes it from the sibling 'de-net-salary.' The purpose is explicit and unambiguous.

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 gives clear when-to-use context: 'No tax tables are baked in: look up the current year's statutory figures and pass them in.' It also advises 'Use consistent units.' However, it stops short of explicitly naming an alternative tool like 'de-net-salary,' so it earns a 4 rather than a 5.

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