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

No annotations exist, so the description carries the full burden. It usefully discloses that negative inputs invert the operation, but says nothing about whether the input date must already be a business day, how weekends/holidays are handled, or how multiple calendars combine into a joint calendar.

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?

A single sentence, front-loaded with the core operation and the negative-value rule packed into a parenthetical. No 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 date-arithmetic tool with a well-described calendar parameter, the definition is roughly adequate. But with no annotations and no output schema, the description omits holiday/weekend semantics and the return format, which an agent would need to interpret results confidently.

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 67%, and the undocumented `days` parameter is exactly where the description compensates: 'negative number' subtracts, which the bare integer schema does not convey. The `date` and `calendar` formats are already well documented in the schema, so the remaining gap is small.

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+resource (add business days to a date) with the twist that negative values subtract, which distinguishes it from a subtraction-only tool. It does not explicitly distinguish itself from sibling count_business_days, but the operation is unambiguous.

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: use this to shift a date by N business days. The parenthetical about negative numbers gives a little conditional guidance, but the description names no alternatives (e.g. count_business_days) and states no when-not conditions.

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