business_days

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

With no annotations, the description carries the full burden of behavioral disclosure. It excels in specifying key behaviors: count_business_days is inclusive, add_business_days accepts negative days, built-in regions work offline, and custom holidays are additive. It does not document error handling or return types, but the output schema is present to cover the return format.

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 extremely well-organized: it starts with a one-sentence purpose, then a compact list of operations, followed by region details and a structured argument list. Every sentence adds necessary information without redundancy, and the formatting makes it 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 moderate complexity (6 parameters, 4 operations, multiple region modes), the description covers all essential aspects: operation semantics, parameter formats, region behavior, and custom holidays. An output schema is present, so the absence of return-type details is acceptable. The only minor omission is behavior when an unsupported region is used without the holidays package, but this is implicitly handled by the 'optional package' note.

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 provides only names and types, leaving all meaning to the description. The description explains each parameter in detail: operation options, ISO date format, negative day support, end_date necessity for counting, valid region values, and custom_holidays format. This fully compensates for the 0% schema coverage.

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 clear purpose: 'Business-day arithmetic honoring weekends and regional public holidays.' It then enumerates four specific operations, making the tool's function unambiguous. This distinguishes it from sibling tools like currency conversion or financial metrics, which are clearly different domains.

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 strong contextual guidance: it lists supported regions, mentions the optional holidays package for broader country coverage, and specifies which parameters apply to which operation. However, it does not explicitly state when to use this tool over alternatives or when it would be inappropriate, falling short of a full usage-guide.

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