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

Annotations provide only destructiveHint=true, and the description usefully softens/clarifies that by noting the operation is reversible (set the status back). It also supplies the status code semantics that no structured field carries. It does not discuss permissions, side effects on related shifts, or notification behavior.

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 dense sentence carries the mutable fields, the status table is inline, and the two constraints plus the API endpoint follow without padding. Front-loaded with the core action; nothing is wasted.

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?

No output schema exists, but this is a mutation tool where the important caller knowledge — mutable fields, status values, pairing constraint, reversibility, and endpoint — is all present. It stops short of noting permission requirements or the effect of overwriting existing approved time off.

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 baseline is 3, but the description meaningfully exceeds the schema by decoding the status integer (0 pending, 1 canceled, 2 accepted/approved, 3 expired, 4 denied) — the schema only says 'New status.' with a 0-4 range. It also reinforces the start_time/end_time pairing rule.

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 (Change) and resource (a time-off request), then enumerates exactly what is mutable: status, dates, and hours. It is clearly distinguishable from siblings like wheniwork_create_time_off_request, wheniwork_get_time_off_request, and wheniwork_update_shift.

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?

Gives concrete operative context — the full status code mapping, the requirement that start_time and end_time be supplied together, and the fact that the change is reversible. It does not, however, explicitly route the agent away from sibling tools such as the read-only get_time_off_request.

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