is_holiday

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

With no annotations, the description carries the full burden. It states that the tool returns the holiday name if the date is a holiday and mentions an authoritative public-holiday dataset, which adds helpful context. However, it does not disclose the exact return format for non-holiday dates, invalid country codes, or edge cases, leaving some ambiguity.

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 long, immediately states the core purpose, and avoids unnecessary detail. It is well-structured and front-loaded with the action and expected result.

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 only two clearly described parameters, and the description covers the main purpose and conditional output. However, because there is no output schema, it would be more complete to explicitly state what happens when the date is not a holiday or when the country code is invalid, which is a minor gap.

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 provides complete descriptions for both parameters with 100% coverage. The description echoes the ISO 3166-1 alpha-2 code requirement but does not add significant semantic detail beyond what the schema already specifies, so a baseline score of 3 is appropriate.

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 checks whether a given date is a public holiday in a specified country and returns the holiday name if applicable. It is specific about the input (date and ISO country code) and the output behavior, making it easily distinguishable from the sibling tools, which are mostly time/date conversion or generic utilities.

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 for when to use the tool: to check if a date is a public holiday in a country. It does not explicitly mention when not to use it or alternative tools, but the intended use case is obvious and no sibling tool directly competes with this functionality.

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