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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false, and openWorldHint=false, so the safety profile is fully covered. The description adds the meaningful behavioral fact that the result depends on a country's working-day calendar, which explains why a country code is required. It stops short of saying whether the returned date is guaranteed to be a business day, what happens with an unknown country code, or the output format.

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 twenty-word sentence with zero filler, and the operative concept (N working days from a start date) is front-loaded. Nothing is redundant with the title, though the terse phrasing leaves the sentence feeling more like a type signature than a description.

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 three-parameter, side-effect-free date utility with no output schema, the essentials are present, but the description should say what the return value looks like (a YYYY-MM-DD string, presumably) and how invalid country codes or out-of-range offsets are handled. Annotations cover safety and the schema covers input formats, so the remaining gap is modest rather than severe.

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%: date and country are documented in the schema, while days is not. The description compensates partly by explaining that a negative days value moves backwards and that date is a start date, which is the key semantic the bare integer property lacks. It still does not clarify the calendar/holiday source used for the country or any edge-case behavior at the ±1000 bounds.

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 computation: a date offset by N working days from a start date, with direction determined by the sign of N. That is clearly distinguishable from counting helpers among the siblings, though it never names or contrasts with count_business_days or is_business_day. It is a noun-phrase fragment rather than a verb phrase, 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?

There is no when-to-use guidance, no mention of the sibling tools that do adjacent things (count_business_days, is_business_day), and no statement of prerequisites or limitations beyond the parenthetical about negative values. An agent must infer from the name alone which of the several date/holiday siblings to pick.

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