calendar.business-days

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

Without annotations, the description discloses key behaviors: holiday awareness for 200+ countries, custom weekends, and itemized skipped holidays. It explains inclusive/exclusive counting for date ranges. However, it does not explicitly state that the tool is read-only or safe, nor does it mention rate limits or auth requirements.

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 well-structured with the main purpose front-loaded, followed by the three modes. Every sentence adds useful information, though it is somewhat lengthy. Minor room for tightening without losing detail.

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 7 parameters with full schema coverage and no output schema, the description explains the three calculation modes, custom weekends, and holiday types. It mentions that skipped holidays are itemized, hinting at output structure. It is largely complete for agent usage, though explicit return format could improve 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?

The input schema covers all 7 parameters with descriptions (100% coverage). The description adds value by explaining parameter relationships (XOR between end and addDays), the behavior of start alone, and the meaning of region, country, types, and weekend, providing context 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 clearly states the tool is a 'holiday-aware business-day calculator for 200+ countries' and specifies its use for 'payment terms, SLA deadlines, and delivery dates.' It lists three distinct modes (addDays, end, start alone), differentiating it from related tools like calendar.holidays.

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 explicit usage guidance by explaining the three modes and when to use each (e.g., 'start+addDays shifts a date by N business days'). It gives context for payment terms and SLAs but does not explicitly mention when not to use this tool or list alternatives beyond the implied sibling tools.

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