Public holidays

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

Annotations already declare readOnlyHint=true, destructiveHint=false, and idempotentHint=true, so the safety profile is covered. The description adds valuable behavioral context: the scope (207 countries), the estimation of Islamic-calendar dates, and the inclusion of 'next holidays' in output. This goes beyond annotations and helps set expectations.

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 captures the core purpose, scope, and a key caveat. Every phrase adds value: the two usage modes, geographic scope, country count, and estimation note. No filler or redundancy.

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 complexity (4 params, output schema present, annotations covering safety), the description is fairly complete. It explains the main behaviors and limitations. Minor gaps like the exact output structure or pagination are not critical because an output schema exists. Slightly more could be said about what 'next holidays' means, but it is adequate.

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 high (75%+), so parameters are already documented. The description reinforces the meaning of 'where' (country/state/city) and the two usage modes (year or date), but does not add new parameter-specific semantics beyond what the schema provides. Baseline 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's function: retrieving holidays for a country/state/city for a year, or checking if a date is a working day. It specifies the resource (holidays) and the verb (get/check), and distinguishes from siblings like business_days or date_info by focusing on holiday data specifically.

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 contexts (yearly holidays, working-day check) but does not explicitly name alternative tools or conditions for when to use this tool versus siblings. It lacks explicit 'when-not-to-use' guidance, leaving the agent to infer from the tool's name and scope.

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