is_business_day

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

No annotations are provided, so the description carries the full burden. It discloses the key behavioral trait that the weekend is fixed to Sat/Sun irrespective of the country parameter, and it warns about incorrect results for non-standard weekend countries. It also states the return structure (answer plus reason). This is transparent for a read-only check, though it does not mention any potential side effects or limitations beyond the weekend caveat.

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 two sentences with zero fluff. The first sentence states the purpose and return value, and the second delivers the critical caveat. It is front-loaded and easy to scan.

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 tool's simplicity (2 params, no output schema), the description covers the essential context: it explains the return includes an answer and a reason (weekend/holiday/business_day), and it highlights the country-related pitfall. It could specify the exact format of the 'answer' (e.g., boolean) but that is minor. Overall, it is complete enough for an agent to use 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?

The schema already documents both parameters with 100% coverage, including the date format and the country's effect on holidays but not the weekend. The description repeats the weekend caveat that is already in the schema's country description, adding no new semantic meaning beyond what the schema provides. Thus the baseline score of 3 is appropriate.

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 states the tool's function: 'Check whether a date is a Polish business day — Monday–Friday and not a public holiday.' It specifies the verb (check), resource (date), and scope (Polish business day). It also differentiates from siblings like is_holiday by focusing on business-day status and mentions the return value (answer plus reason).

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 provides important usage context by warning that the weekend is always Saturday/Sunday regardless of country and that results are wrong for countries with different weekends. However, it does not explicitly state when to use this tool versus siblings like is_holiday or count_business_days, nor does it mention any exclusions or alternatives.

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