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

The description adds useful behavioral context beyond the non-informative annotations: it returns an EMP-NNNN id, explains how balances are calculated ('approved plus pending leave against allowance + carried-over'), and notes unlimited free-tier usage. This helps an agent predict side effects and follow-up 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?

The description is short and front-loaded with the core action and return value. The phrase 'Give their annual paid-leave allowance...' is slightly awkward and could be read as a user instruction, but the overall structure earns its place.

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 creation tool with a rich schema and no output schema, the description conveys the return idantification format and the balance policy relevant after creation. It is mostly complete, though it could clarify duplicate handling or non-idempotency more explicitly.

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 the baseline is 3. The description goes slightly further by explaining how annualAllowance and carriedOver interact in balance calculations, which adds meaning beyond the field-level schema descriptions.

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 action ('Add an employee to the leave tracker') and a concrete result ('return their EMP-NNNN id'), making it immediately distinguishable from sibling leave tools. It clearly identifies the resource and the operation.

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?

No guidance is given about when to use this tool versus alternatives such as leave_import or other leave tools. The description explains what the tool does but does not state when it should be preferred or any exclusions.

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