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

Annotations already declare this is a safe, idempotent, closed-world read (readOnlyHint/idempotentHint/openWorldHint=false). The description adds real value beyond them: the exact coverage layer (nationwide statutory paid-rest holidays over a Sat-Sun baseline), the exclusion of municipal/local schedules, and the staleness caveat that future annual calendars need refreshed official evidence. It also documents the traversal formula, well beyond what annotations provide.

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 content is front-loaded with purpose and usage, which helps, but the block is bloated with redundant sections (inputs restated, full output field list despite an output schema, REST fallback, docs URL) and one garbled sentence. Every sentence does not clearly earn 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?

For a two-parameter deterministic calculator with an output schema, the definition covers usage, scope limits, formula, and error-avoidance (REST fallback). Nothing essential to calling it correctly is missing, though it redundantly enumerates return fields that the output schema already supplies.

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 schema already documents both parameters, and the description largely restates the same input names plus a JSON example. The formula line adds minor semantic context on how working_days is applied, but parameter-level meaning beyond the schema is thin. Baseline 3 is appropriate.

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 names a specific verb+resource pair ('Adds or subtracts Colombia authority-scope working days in exact coverage') and the 'What it computes' line reinforces scope. It clearly distinguishes this offset tool from the sibling check_co_working_day and count_co_working_days by framing the operation as an addition/subtraction of a signed offset.

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?

It gives strong positive guidance ('Use this when you need a deterministic Colombia working-day offset', 'Call this tool directly') and a do-not-use clause covering uncovered municipal/departmental/school/bank/sector schedules. The exclusion sentence is garbled ('Do not use this when this package covers...') and it never names a concrete alternative sibling, so it falls short of a clean 5.

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