営業日判定

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

Beyond the readOnlyHint annotation, the description discloses that it returns the reason (weekday or holiday name) for non-business days, defaults to Japan time when date is omitted, and supports 2020-2099. This gives useful behavioral context for callers.

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 two sentences, covering purpose, return reason, default, and supported range with no redundancy. It is front-loaded with the core function and efficiently structured.

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?

The tool is simple with one optional parameter and no output schema. The description explains the key behavior and return of reason, but does not specify the exact return data structure (e.g., boolean plus reason field). Nevertheless, it is adequate for its simplicity.

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 already describes the 'date' parameter with its meaning and default behavior, and the description does not add any additional parameter details beyond what the schema provides. Therefore baseline of 3 applies given 100% 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 clearly states the tool determines if a date is a business day (weekday and not a holiday), returns the reason for non-business days, and supports an optional date with default to today. It distinguishes from sibling tools like adding business days or calculating deadlines by its scoped function.

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 its usage for checking business day status but does not explicitly mention when not to use it or name alternative tools. Agents can infer it based on the description, but there is no direct guidance on choosing between this and sibling tools.

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