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 discloses that GB defaults to England and passes subdiv codes for UK nations or US states. However, it does not specify the return type (likely boolean) or behavior for invalid dates, unsupported countries, or error cases. This is adequate but lacks depth.

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, front-loaded with the core function and format, followed by usage guidelines and parameter details. Every sentence adds value with no wasted words.

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 no output schema and 3 parameters, the description covers usage context and parameter semantics well. It mentions subdivisions for GB and US but does not explicitly state that only GB and US are supported, nor does it describe the return value. This is still complete enough for a simple check tool.

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 schema has 0% description coverage, so the description compensates well. It explains the date format, country default (GB), and provides examples for subdiv (SCT, WLS, NIR, US state code). It adds meaning beyond the schema but could be more precise by noting that only GB and US are supported.

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 if a date is a public/bank holiday, specifies the date format YYYY-MM-DD, and mentions use cases like business-day deadlines and delivery SLAs. It distinguishes from siblings like next_holiday by focusing on checking a specific date.

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 explicitly says 'USE THIS when computing business-day deadlines, delivery SLAs, or next working day', providing clear context. It also gives examples of subdivisions (SCT, WLS, NIR, US state code) but does not explicitly mention when not to use it or directly name alternatives like next_holiday.

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