is_japan_holiday

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 states the core function but does not disclose behavior for invalid dates, return format, or any edge cases. Since an output schema exists, the return type might be visible elsewhere, but the description itself offers minimal behavioral insight.

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 a single, well-structured sentence that immediately conveys the tool's purpose and parameter format. No wasted words, and the essential details are front-loaded.

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 simple single-parameter tool, the description provides sufficient context: what the tool does and the date format. The presence of an output schema reduces the need to explain return values. Minor gap: no mention of error handling or edge cases, but given the low complexity, this is acceptable.

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 description coverage is 0%, but the description compensates by specifying the exact format 'YYYY-MM-DD' for the 'day' parameter. This adds meaning beyond the bare string type, clarifying the expected input format.

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 uses a specific verb 'Check whether' with a clear resource 'date (YYYY-MM-DD)' and outcome 'Japanese national holiday'. It clearly distinguishes the tool's purpose from siblings like lookup_corporate_number or japan_holidays, which have different focuses.

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 implies usage: to test if a given date is a public holiday. However, it does not explicitly mention when to prefer this tool over siblings like japan_holidays, which likely lists holidays. No alternative or exclusion is stated, so guidance is only implied.

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