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

With no annotations, the description carries the behavioral burden and adds meaningful details: weekend and holiday skipping, ISO country code for holidays, pricing via x402, and an example output. It still leaves gaps around the optional country default and the meaning of the 'inclusive' field shown in the example.

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 purpose is front-loaded, the use cases are compact, pricing is stated in one sentence, and the example output is a concise illustration of the return value. There is no evident filler.

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 three-parameter calculator with no output schema and no annotations, the description covers the core calculation, holiday behavior, cost, and a sample result. Minor gaps remain around default country behavior and the inclusive flag, but the definition is largely sufficient for correct invocation.

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 coverage is 100%, so the input schema already documents start, end, and country formats. The description adds that country relates to national public holidays, but it does not further explain parameter behavior or defaults beyond the schema.

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 states a specific action and resource: counting working days between two dates while skipping weekends and national public holidays. It is clear what the tool does, but it does not explicitly contrast itself with the sibling public_holidays tool.

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?

It names concrete use cases such as SLAs, invoice due dates, shipping, and legal deadlines, which gives clear context for when to use it. It does not provide explicit exclusions or point to alternatives like public_holidays for listing holidays.

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