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

With no annotations, the description carries full burden. It explains the calculation formula (2.5/month) and returned values (days earned and working day equivalent), which is transparent for a read-only computation. However, it does not discuss error handling, permissions, or behavior with zero months. Still, it provides sufficient behavioral insight.

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 extremely concise: two sentences covering purpose, inputs, outputs, and a sibling reference. No unnecessary words, and the most important information (what it computes) is front-loaded. Every sentence adds value.

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?

Given the tool's simplicity (2 parameters, straightforward calculation) and presence of an output schema (context signal), the description adequately explains inputs and outputs. It lacks details on edge cases or error behavior, but for this type of tool, it is sufficiently complete for an agent to use correctly.

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 input schema has full coverage with clear descriptions for both parameters. The description adds context by naming the parameters as 'months worked' and 'contract type' and linking them to the 2.5/month rule. Since schema already explains them well, the description adds moderate additional value, not enough for a 5.

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 clearly states the tool computes French paid vacation days using the 2.5 per month rule, specifies inputs (months worked, contract type), and outputs (days earned and equivalent working days). It also distinguishes itself from siblings by explicitly mentioning 'list_bundles' for related calculators, making the purpose unambiguous.

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 indicates usage for HR planning, which provides context. It mentions a sibling tool for related calculators, offering some guidance. However, it does not explicitly state when not to use this tool or list alternatives beyond the sibling reference, so it falls short of a 5.

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