Check whether a specific date is a public holiday in Poland or another supported country. Returns holiday details for the date, or null if it is a regular day.
Check whether a specific date is a public holiday in Poland. Returns holiday details if yes, null if no.
| Name | Required | Description | Default |
|---|---|---|---|
| date | Yes | YYYY-MM-DD | |
| country | No | ISO 3166-1 alpha-2 country code (default PL) | PL |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description must disclose behavior. It states the return value (holiday details or null) and implies read-only operation. However, it does not clarify scope (e.g., only national holidays, or does the country parameter override the 'Poland' mention), nor does it mention potential edge cases like timezone or date format handling. Adequate for a simple check but with gaps.
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?
One sentence, front-loaded with the core purpose, zero waste. Efficient and to the point.
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 boolean-like check with two parameters, the description provides the essential return behavior. However, it lacks detail on the exact structure of 'holiday details' and does not clarify that the country parameter can be used to check other countries, which is important given the default. The absence of an output schema increases the need for this information, so it is not fully complete.
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 covers 100% of parameters with descriptions (date format and country code default). The tool description adds no additional meaning beyond the schema, so it meets the baseline of 3 without enhancement.
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?
States the specific action: checking whether a date is a public holiday in Poland, and specifies the return behavior (holiday details or null). Clearly distinguishes from siblings like list_holidays (which lists) and is_business_day (which checks business days) by naming the resource and condition.
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?
Provides no guidance on when to use this tool versus alternatives. Does not mention that is_business_day is for a different check, nor any exclusions. The only context is the tool name and the sibling list, but the description itself is silent on selection criteria.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.