次の祝日

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

Annotations already declare readOnlyHint=true and openWorldHint=false, covering the safety and scope profile. The description adds useful behavioral context: the timezone for the default date (Japan time) and the output contents (holiday date and days remaining). This aligns with the annotations and adds value beyond them.

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, front-loaded sentence that efficiently conveys the essential behavior: the operation, the input, the default, and the output. Every word earns its place, with no redundancy or filler.

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 read-only tool with one optional parameter and no output schema, the description fully explains the return value and input semantics. It does not need to describe return formatting or error handling given the straightforward nature, and the annotations already cover the safety profile.

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 fully describes the 'from' parameter (start date, default today), so the baseline is 3. The tool description enhances this by specifying '日本時間' (Japan time) for the default, adding a meaningful detail not present in the schema description. Thus, it goes slightly 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 returns the nearest holiday on or after a specified date (default today) and the number of days remaining. This is a specific verb+resource combination that distinguishes it from sibling tools like jp_list_holidays (which lists holidays) and jp_date_info (which provides date details).

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 clear context: use it to find the next holiday from a starting date, with today (Japan time) as the default. However, it does not explicitly mention when not to use it or compare against alternatives such as jp_list_holidays, so it stops short of the highest bar.

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