count_business_days

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

No annotations are provided, so the description fully bears the burden of disclosing behavior. It states that both endpoints are included by default (hinting at the inclusive parameter), that weekends and public holidays of the specified country are excluded, and that the output includes a count plus a breakdown of weekend days and named holidays. This is sufficient for a counting tool, though it doesn't specify error handling or rate limits.

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 concise, consisting of two sentences with no wasted words. It front-loads the key instruction 'USE THIS', making it immediately clear. Every sentence adds value: the first explains why the tool is needed, and the second explains what it does and returns.

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?

The tool has 5 parameters, all described in the schema. There is no output schema, but the description mentions the return value (count plus breakdown). Given the complexity of a date-counting tool, the description provides enough context for an agent to understand input, behavior, and output. It could be more complete by noting edge cases like invalid dates, but it's adequate.

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 each parameter is already described in the schema. The description adds minimal additional meaning: it mentions the default inclusive behavior of both endpoints, which aligns with the inclusive parameter. This slight addition justifies a score slightly above baseline (3), as 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?

Clearly states the tool counts working days between two dates, accounting for holidays and weekends of a specific country. The description uses a specific verb 'count' and resource 'business days', and the name itself distinguishes it from sibling tools like add_business_days, is_business_day, etc.

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 instructs to use this tool for counting working days instead of estimating, noting that LLMs commonly miscount due to holidays or weekend rules. It implies the tool is accurate but does not explicitly mention when not to use it or contrast with siblings beyond the name. Still, it provides clear context for its primary use case.

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