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

Annotations already declare readOnlyHint, idempotentHint and destructiveHint=false, so safety is covered. The description goes further by disclosing the deterministic nature, the exact-coverage scope, the day-by-day formula, and the REST fallback URL — genuinely additive behavioral context. It falls short of 5 only because it omits edge-case behavior around the working_days=0 boundary.

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 content is front-loaded with the when-to-use and when-not-to-use guidance first, then inputs, example, outputs, formula and fallback. It is longer than necessary — the long Outputs enumeration duplicates the output schema — but every other sentence earns its place.

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, the description need not explain return values, yet it still is complete enough to call correctly: inputs, a concrete JSON example, the computation formula, and a REST fallback. The only mild redundancy is the output field list, which does not reduce completeness.

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 the schema documents both start_date and working_days with formats, bounds and examples. The description lists the same two inputs and repeats a JSON example, adding no meaning beyond the schema, so the baseline of 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?

The description states a specific verb and resource — adds or subtracts Poland authority-scope working days — and explicitly carves out its scope (deterministic Poland working-day offset). It clearly distinguishes itself from the dozens of country siblings like add_de_working_days and add_fr_working_days by naming the jurisdiction.

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?

It contains explicit 'use this when' guidance (deterministic Poland offset, return the calculation rather than answering from memory) and a 'do not use this when' section excluding nationwide statutory-holiday-only, employer, sector, school, bank and local schedules. This tells the agent both when and when-not to select the tool.

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