Four well-defined tools with complete schemas, clear descriptions, and proper parameter validation. All tools have explicit input schemas with type constraints (regex patterns, min/max bounds). Descriptions are detailed and domain-specific (Japanese business day calculations). Tool names follow verb_noun convention (jp_is_business_day, jp_add_business_days). All parameters have descriptions and type constraints. Structured output with both text and structuredContent fields. Main gaps: no error recovery guidance in descriptions, no pagination (not applicable here), and descriptions could be more concise (avg ~180 chars, slightly above baseline 194 but acceptable for domain specificity).

• Add English translations to all parameter descriptions and error messages. Current Japanese-only text limits LLM comprehension and international usability.
• Enhance error messages with recovery guidance: 'Date out of range (2020-2099). Try a date within this range.' instead of bare 'Out of range'.
• Add explicit note to jp_business_days_between description: 'start must be <= end. If start > end, an error will be returned.'
• Consider adding a 'supported_year_range' field to tool responses or a separate discovery tool that returns '2020-2099' so LLMs know the constraint upfront.
• Add examples to descriptions showing typical use cases: 'E.g., to find the deadline 10 business days before a contract expiration, use jp_calc_deadline.'