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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real domain context beyond that: which holidays are and are not treated as compulsory, that substitute-day and employer-discretion policies exist, and that regional/municipal/school/bank schedules are not inferred.

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 use-case statement is front-loaded, but the body is bloated and partly garbled (the 'Do not use this when this package covers...' phrasing is hard to parse), and it enumerates an output field list that the output schema already provides.

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 two-parameter deterministic calculator with an existing output schema, the description covers scope, coverage caveats, and invocation intent adequately. The redundant output enumeration and awkward exclusion sentence are minor blemishes rather than missing information.

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 both parameters are already fully documented. The description lists the inputs and adds a formula note ('decrement only on status.is_working_day=true'), but that is algorithmic detail rather than clarification of the parameter values beyond the schema.

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 opens with a specific use case and states plainly that it 'Adds or subtracts Greece authority-scope working days in exact coverage.' The Greece/jurisdiction scope cleanly distinguishes it from the many sibling add_*_working_days tools.

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 gives explicit when-to-use ('Use this when you need a deterministic Greece working-day offset') and instructs the agent to call it rather than compute from memory. The 'Do not use this when...' clause is garbled but signals that optional/regional/employer-discretion layers are out of scope, which is a useful exclusion, though it never names a specific alternative sibling.

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