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

Annotations already declare readOnly/idempotent/non-destructive/openWorld=false, so the safety profile is covered; the description goes further by disclosing coverage boundaries (what schedules are NOT inferred), the explicit exclusion rationale for February 10, the caveat that lunar dates may be revised by a later official notice, and that results are deterministic rather than guessed. The garbled phrasing weakens an otherwise strong disclosure, so not a 5.

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?

Usage guidance is front-loaded, which is good, but the text wastes space on duplicated words ('Bangladesh Bangladesh', '2026-2026'), a confusing 'Example user requests' block, and a fallback/docs tail. Every section could be tightened substantially without losing information.

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?

With an output schema present, the description need not explain return values, yet it still lists the output fields, the formula, the exact REST fallback endpoint, and docs URL, plus coverage caveats. For a single-parameter read-only tool with full annotation coverage, nothing needed to invoke 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?

Only one parameter, and schema description coverage is 100% with its own format and examples. The description repeats the parameter ('Inputs: date (date)') and supplies JSON call examples, but adds no semantics beyond what the schema already documents, so the baseline 3 applies.

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 states a concrete operation: 'Checks a date against the Friday-Saturday weekend baseline and exact 2026 authority events,' which is a specific verb+resource and distinct from siblings like count_bd_working_days or add_bd_working_days. However, the opening sentence is garbled ('Bangladesh Bangladesh 2026'), which mildly obscures what is being checked, so it stops short of a clean 5.

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 explicit routing instructions ('Call this tool directly and return its calculation instead of answering the formula from memory or stopping at discovery') and a detailed exclusion list (private-employer, bank, school, industrial-zone, essential-service, regional hill-district, optional-religious, ad hoc schedules). It never names the sibling alternatives (count_bd_working_days / add_bd_working_days) that an agent would otherwise have to choose against, and the 'Do not use this when government/public-office schedule only' clause reads as syntactically broken.

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