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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds value the annotations cannot: it documents the shape of the response (allowance, taken, booked, remaining) in the absence of an output schema. It omits any note on pagination or volume of years returned.

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?

Two tight sentences: the returned content first, the filtering rule second, then the raw endpoint as a trailing identifier. Every clause carries information and nothing is padded.

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?

With no output schema, the description usefully enumerates the returned balance fields, and the param count is small and fully documented. What is missing is a statement of whether multiple years are returned by default and any auth/permission prerequisites, but for a simple read getter this is close to complete.

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%, and the schema already explains for_date as 'Only the holiday year that includes this date (yyyy-mm-dd)' plus employee_id as the Breathe employee id. The description's for_date sentence essentially restates the schema, adding no format or edge-case detail beyond it.

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 names a specific resource (an employee's holiday years) and enumerates the fields returned (start/end, allowance, taken, booked, remaining), so an agent knows exactly what it gets. It doesn't differentiate itself from the conceptually adjacent sibling breathehr_list_holiday_allowances, leaving some selection ambiguity.

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 gives one concrete usage rule — pass for_date to narrow to the single year containing that date — which implies the no-param case returns all years. However, there is no guidance on when to use this versus list_holiday_allowances or how employee_id is obtained, so usage is only partially implied.

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