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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is fully covered by structured data. The description's 'Limitations: read-only' simply restates that, and adds no behavior beyond the endpoint path (no auth requirements, error cases, or multi-workspace 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?

Single front-loaded sentence with the action first, followed by a terse limitation clause. No padding or boilerplate; only the redundant read-only note costs it a point.

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 read-only getter with no output schema, the description is minimally adequate — the agent knows what it retrieves and that it is safe. It omits what the balance response contains and any note about multi-workspace/account_id behavior, which matters for a 7-parameter tool.

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?

The description only names user_id and policy_id implicitly via the URL template; it adds no meaning beyond the schema, which documents 71% of parameters including account_id's multi-workspace requirement. With moderately rich schema coverage, the baseline of 3 is appropriate.

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 and resource ('Gets a user's balance status for a policy') and even names the endpoint path, so the operation is unambiguous. However, it does not distinguish itself from the closely related sibling list_timeoff_balances, so the agent gets no help choosing between the two.

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 guidance on when to use this tool rather than list_timeoff_balances or calculate_timeoff_amount, nor any prerequisite or context statement. The only qualifier given is a read-only limitation, which is not usage guidance.

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