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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so safety is covered. The description adds genuine value on top: it enumerates what is NOT computed (union of Christian calendars, non-Christian holidays, public-sector bridge/recovery days, individual rosters, payroll/legal deadlines) and states that other bases and future years are unsupported. This is strong scope disclosure beyond the annotations.

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 definition is bloated and front-loading is undermined by a garbled 'Do not use this when' sentence, malformed 'example user requests' fragments, and a 20-item output enumeration that is redundant given the output schema exists. Multiple sentences do not earn their place or parse cleanly.

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?

Because an output schema exists, the long Outputs list is unnecessary, and the scope/restriction coverage is thorough. But the nonsensical 'do not use' clause leaves the agent without a clear alternative, and the boundary conditions are stated in fragments rather than a coherent set of prerequisites, leaving real gaps in the guidance.

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%, so the schema already documents all four parameters, and the description largely restates the input list. It does add some semantic framing for calendar_basis ('the basis selects dates, not a person's identity or religion') and supplies two complete JSON argument examples, which is a modest gain over the schema baseline of 3.

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 'What it computes' sentence states a specific verb+resource ('Adds or subtracts Romania authority-scope working days') and the tool name itself carries the country scope that separates it from the ~65 country siblings. However, the muddled 'Do not use this when' sentence and fragments ('around January 24 remains a statutory holiday') dilute the clarity, so it falls short of the crisp sibling-differentiation a 5 requires.

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 opening 'Use this when you need a deterministic Romania working-day offset' gives minimal positive context, and the instruction to call directly rather than answer from memory is useful. But the 'Do not use this when...' clause is grammatically broken and names no alternative tool, even though obvious candidates (check_ro_working_day, count_ro_working_days) exist. There is no real when-not guidance or routing to siblings.

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