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

Annotations already declare readOnly, idempotent, non-destructive, closed-world. The description adds real behavioral context beyond that: no next-Monday compensation, personal/bank-only/school/local/employer calendars are out of scope, and future years require a separately verified package. This meaningfully extends the safety profile with scope boundaries.

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?

Heavily bloated and repetitive: 'Malta Malta 2026' duplication, the enum/scope caveats restated multiple times, and a full enumeration of output fields that the output schema already defines. The front-loaded use/don't-use framing is good, but much of the body does not 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 date-check tool with an output schema, the description covers scope, exclusions, formula, and worked JSON examples, so an agent has what it needs to call it correctly. It over-explains return values the output schema already provides, but nothing essential is missing.

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% and both parameters are documented in the schema, so the baseline is 3. The description restates the work_schedule meaning ('mon_fri_planning baseline BEFORE individual annual/compensatory leave') and supplies the formula, but adds little semantics the schema does not already carry.

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' line states a specific verb and resource: 'Checks a date against the Saturday-Sunday weekend baseline and exact 2026-2026 authority events.' Being Malta-scoped, it clearly distinguishes itself from the many check_xx_working_day siblings. Garbled phrasing like 'deterministic Malta Malta 2026 fourteen named statutory holidays' creates noise, but the operation is still identifiable.

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?

Explicit 'Use this when...' and 'Do not use this when...' framing, plus a directive to 'Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery.' The negative clause is syntactically mangled, and no alternative sibling tool is named, so it stops 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.