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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely useful behavioral context beyond that: the 8-scenario cap, the exact output breakdown, and the important constraint that amounts remain in each country's currency with no FX conversion.

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, zero filler, and the core capability plus the output shape are front-loaded. Every clause carries information the agent needs.

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 an output schema present, return values need not be re-specified, and the description still summarizes them plus the currency caveat. What is missing is any statement of prerequisites or failure modes (e.g. the DE 67+ birth-year rejection noted only in the schema).

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 the baseline is 3, but the description earns extra credit by surfacing the maxItems=8 limit and the currency semantics (local currency, no FX), which the schema only implies via "in EUR (DE) or GBP (UK)". It still doesn't hint at the country-specific profile objects inside each scenario.

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 concrete verb and resource ("Runs up to 8 gross-to-net scenarios and returns them side by side") and enumerates the returned quantities (net, deductions, employer cost, tax/social split). It clearly reads as a multi-scenario comparison tool, but it never names the sibling calculate_net_salary to explain why an agent would pick this one over a single-scenario calculation.

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?

Usage is implied by "up to 8 scenarios ... side by side" and the "no FX conversion" caveat, which tells the agent results are not directly comparable across currencies. However, there is no explicit when-to-use sentence and no mention of the alternatives (calculate_net_salary for a single case), so the boundary with siblings is left to inference.

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