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

Annotations already carry readOnly/idempotent/non-destructive, so the description's added value is the iteration formula ('move one day at a time; decrement only when selected status is working') and the note that results are deterministic. That is genuine behavioral context beyond structured fields, though auth/rate-limit behavior is untouched.

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?

Front-loaded well with the use case and exclusion, but the long enumeration of output fields duplicates a structured output schema that already exists, and the REST-fallback URL plus docs link pad the body. Several lines do not earn their 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 3-param, deterministic calculation tool with annotations and an output schema, the description covers purpose, exclusions, the algorithm, and a fallback endpoint, leaving little an agent needs missing. The redundant output list is the main flaw rather than a gap.

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 all three parameters with richer detail (workweek meaning, start_date Gregorian scope, signed offset semantics). The description's 'Inputs:' line and JSON example simply restate what the schema provides, adding no new meaning.

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?

States a specific verb ('adds or subtracts'), resource ('Uzbekistan 2026 workdays'), and scope constraint ('required five-day or six-day schedule'). An agent can distinguish it from check_uzbekistan_working_day and count_uzbekistan_working_days by the offset semantics without opening a schema.

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?

Provides explicit when-to-use ('you need a deterministic workday offset and know the workweek variant'), when-not ('workweek or employer/shift scope is unknown'), and a directive to call directly rather than compute from memory. It stops short of naming the alternative siblings (check_/count_) that a confused agent might otherwise pick.

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