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

Annotations already declare read-only/idempotent/closed-world, and the description adds real behavioral context beyond them: calendar-scope constraints (government/public-office only), why February 10 is excluded, and the caveat that lunar dates may be revised by later official notice. This is exactly the kind of audit-relevant disclosure annotations cannot carry.

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?

Long, but front-loaded with the decision rule and organized under labeled sections (What it computes / Inputs / Outputs / Formula / Fallback / Docs). The outputs list and REST/formula details are mildly redundant given the output schema exists, keeping it from a 5.

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?

Despite the complexity (audit-grade holiday logic, scope caveats, fallback endpoint), the description covers when to use, what is and isn't inferred, inputs, outputs, and a formula. With an output schema present, it needn't explain returns further — nothing an agent needs to call it correctly 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%, so the baseline is 3; the description earns extra by listing all four inputs with types/optionality and providing a complete JSON argument example. It does not add date-format rules beyond the schema's 'date' format, so it stops short of 5.

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+resource+scope ('Counts authority-scope working and non-working dates in a range') and is clearly differentiated from the nearest siblings (add_bd_working_days, check_bd_working_day) by framing itself as the counting/audit tool. An agent can identify it without opening the 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?

Explicit both ways: 'Use this when you need an auditable Bangladesh working-day count... Call this tool directly instead of answering from memory or stopping at discovery,' followed by a detailed 'Do not use this when' clause enumerating excluded schedule types. Routing to alternatives is implied via the sibling naming pattern and the strict scope exclusions.

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