is_business_day

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

No annotations are provided, so the description fully handles behavioral disclosure. It explains what constitutes a business day (not weekend, not holiday), notes case-sensitivity of subdiv, states that omitting subdiv only considers nation-wide holidays, and mentions that category filtering is not supported. It also lists raised ValueError conditions.

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 front-loaded with the main purpose and structured with Args/Returns/Raises sections. It is reasonably concise, though the subdiv description includes an example that could be slightly shortened. Overall, every 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?

Given the tool's moderate complexity and missing annotations, the description is complete. It explains all parameters, the return value (dict with specific keys), and error conditions. The output schema exists (implied by the description's Returns section), so no further detail is needed on return values.

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?

With 0% schema description coverage, the description compensates fully. It explains the ISO 8601 date format, case-insensitivity of country code, case-sensitivity of subdiv with an example, and the effect of omitting subdiv. This adds meaning far beyond the bare schema types.

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 'Check whether a date is a business day for a given country (optionally a subdivision)' with a specific verb and resource. It distinguishes from sibling tools like 'business_days_between' and 'list_holidays' by focusing on a single date check.

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 explicitly says 'Use this when an agent needs to know if a specific calendar date is a working day'. While it doesn't explicitly list alternatives, the context from sibling tool names implies when not to use it (e.g., for date ranges use 'business_days_between').

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