Get a user's entitlement balances

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

Annotations only cover the safety profile (readOnlyHint, openWorldHint), yet the description adds real behavioral context: which balance types count down (annual, transfers, pending, booked, taken, untaken, remaining) versus up (sickness: YTD, 6/3 months, 30 days), that pots are also returned, and how booking period/time unit values are named. The include_pots extra-call cost is only in the schema, not the description.

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 single dense paragraph is not front-loaded and packs enumerations into parentheticals, making it hard to parse. Some length is defensible since there is no output schema, but the structure wastes that budget.

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 does carry the return-shape burden and enumerates balance fields and pots reasonably well. However, it omits error/missing-user behavior and the booking-period vocabulary it introduces maps to no visible input, leaving the agent unsure whether those values are parameters or output fields.

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%, so all three parameters are already documented, establishing the baseline of 3. The description's 'booking period and time unit numbers' sentence references values that do not correspond to any input parameter, which adds confusion rather than meaning for the actual parameters.

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 opening line 'Entitlement balances for one user' names a specific resource and scope, and the singular 'one user' contrasts implicitly with the list_* siblings. It is clear what the tool fetches, though it never states the verb (get/read) explicitly and buries the scope in a long second sentence.

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: nothing tells the agent when to prefer this over get_user, get_user_rota, or get_absence. The only hint is the phrase 'for one user', leaving the agent to infer the trigger condition.

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