Korean public holidays

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

No annotations are provided, so the description carries the full burden. It usefully discloses a non-obvious behavioral trait — substitute holidays are included — and that the tool has two modes (range vs single-date check). However, it says nothing about precedence when both 'date' and 'from'/'to' are supplied, timezone handling, or whether the range returns every calendar day or only holiday entries, which matters for a zero-annotation tool.

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 sentences with no filler: the first defines the action and modes, the second justifies usage. The critical capability statement is front-loaded, and no sentence restates the tool name or title.

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 read-only lookup with three optional, fully documented parameters and no output schema, the description covers purpose, scope, and practical relevance adequately. The remaining gap — what happens if 'date' and 'from'/'to' are combined, and the shape of returned holiday records — is minor but non-zero, so this falls short of 5.

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%, so the schema already documents all three parameters including their defaults and date format. The description's split between 'date range' and 'check a single date' maps onto the schema's two modes but adds no format, default, or precedence detail beyond it. Baseline 3 applies when the schema does the heavy lifting.

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 specific verbs and resource: lists South Korean public holidays in a date range, or checks a single date. It also names the scope qualifier 'including substitute holidays' and 'South Korean', which cleanly separates it from the unrelated siblings (subway_route, subway_station, korea_guide). The two operating modes are stated up front so an agent can pick the right invocation mode without opening the schema.

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?

Gives clear usage context ('useful for planning: many shops, banks and offices close, and transport is crowded around Seollal and Chuseok'), which tells the agent when this tool matters. It does not name alternatives or explicit exclusions, but the sibling tools are unrelated domains, so no routing ambiguity exists. Clear context without the 'when-not' clause keeps this at 4 rather than 5.

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