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

It discloses the core behavioral model: school holidays are about 60 working days, a vacation account holds 30 days, a care day costs exactly one vacation day, and a joint family holiday draws from both accounts while covering one day. With no annotations, the description carries the burden and does so meaningfully, though it stops short of describing the output format or edge cases.

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?

Three sentences with no filler: result, underlying model, and intended use case. The most important information is front-loaded, and every sentence 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?

The description explains the computation and roughly what the tool returns—coverage amount and open weeks—but it does not specify whether the coverage figure is days or a percentage or how the weeks list is structured. With no output schema and no annotations, that level of detail would make it fully 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%, so the baseline is 3, but the description adds a useful global invariant: a care day always costs exactly one vacation day. This connects vacationDays, partnerVacationDays, and jointDays into a coherent calculation model beyond what the individual field descriptions say.

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 is specific about what the tool computes: how much of a region's school holidays two vacation accounts cover and which weeks remain open. It clearly states the question it answers for parents, but it does not explicitly distinguish itself from sibling tools like best_bridge_days or plan_vacation.

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?

The description gives clear context for when to use the tool: it answers 'can we cover the school holidays' for parents. It does not mention when not to use it or point to alternatives, but the use case is explicit enough to guide selection.

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