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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered. Beyond that, the description adds real behavioral content: the 2.5 days-per-month accrual rule and the shape of the result (days earned plus working-day equivalent). It does not address edge cases such as part-time proration or the 30-day legal cap.

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 short, front-loaded sentences with no filler: purpose first, then intended use, then inputs/outputs and a cross-reference. Efficient, though the trailing bundle pointer is of marginal relevance to calling this specific tool.

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?

An output schema exists, so return values need not be detailed, and annotations cover the safety profile. For a two-parameter, single-rule calculator the description is essentially complete; only the unaddressed proration/cap behavior keeps it from a 5.

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% for both parameters, so the baseline is 3. The description restates the inputs but paraphrases the 'full_time' boolean as 'contract type', which is slightly imprecise and adds no syntax or constraint detail beyond what the schema already provides.

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?

Names a specific verb and resource ('Compute French paid vacation days earned (congés payés)') and even cites the governing rule (2.5 days/month), which distinguishes it from generic leave tools. It does not explicitly contrast itself with close siblings like calculate_vacation_days_optimal, calculate_leave_days, or calculate_working_days, so it falls short of a 5.

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?

'Use for HR planning' gives only an implied domain of use and offers no when-not guidance or comparison to the many adjacent leave/working-day calculators. The 'See list_bundles' pointer is a helpful navigational hint but is about a discovery tool, not about choosing between alternatives.

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