Time Zone Contract Repair

The problem

Date and time behavior often drifts across API schemas, database columns, and background workers. Naive timestamps, lost zone identities, and broken recurrence logic lead to shifted all-day events and duplicate or missed scheduled jobs.

What it does

• Traces temporal values from user input through validation, storage, and worker execution to find contract drift.
• Identifies naive timestamps, false UTC conversions, and fixed-offset recurrence errors during DST transitions.
• Introduces explicit temporal types and IANA zone validation to replace fragile numeric offsets.
• Repairs overnight availability windows and reporting boundaries to ensure consistency across different server zones.
• Updates mocks, fixtures, and tests to verify time-sensitive logic deterministically without using live clocks.

Frameworks & tools

Works with repository materials including Prisma, Django, SQLAlchemy, BullMQ, Celery, and standard date libraries. Uses local verification tools like Bash, grep, and repository-specific test runners.

Why this beats prompting it yourself

Handling daylight saving gaps, autumn folds, and recurrence expansion requires a strict "time contract" approach that generic prompts miss. This skill enforces a comprehensive audit of every temporal layer, from database session zones to serialization, ensuring patches are bounded and safe.

Use cases

• Fixing all-day calendar events that shift dates when viewed in different time zones.
• Repairing recurring reminders that drift an hour after a daylight saving transition.
• Resolving duplicate background jobs caused by autumn clock changes.
• Standardizing report boundaries so daily exports don't change based on container location.

Known limitations

Does not access live calendars, production databases, or external booking providers. Will not execute data migrations or select organization-wide business time zone policies.