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

With no annotations, the description carries the full behavioral burden. It does add genuine context beyond the schema: the result includes the decree the date was checked against, and weekends only count when the decree names them. Coverage limits, error behavior, and year ranges remain undisclosed.

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?

Two tight sentences with no filler, and the core purpose is front-loaded ahead of the edge-case clarification about weekends.

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?

No output schema exists, so the description usefully characterizes the return content (holiday status plus the decree used) and clarifies the weekend rule. For a one-parameter lookup this is nearly sufficient, though coverage years and behavior for invalid/non-decree dates are omitted.

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 100% (the single date parameter documents YYYY-MM-DD format and type), so the schema already handles parameter semantics. The description adds no further format, timezone, or range detail, making the baseline 3 correct.

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 a specific verb and resource: determines whether a single date is a public holiday or cuti bersama. The phrase 'one date' implicitly separates it from the sibling get_holidays, but the sibling is never named, so the contrast must be inferred.

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?

Usage is implied by 'whether one date is...' — you call it with a single date to test that date. There is no explicit statement of when to prefer this over get_holidays or any exclusion/precondition, leaving the agent to infer the single-date vs. list distinction.

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