Cutoff

Conflicting deadlines should not become confident calendar events. Compare source statements, expose time-zone ambiguity, and export a planning marker only when every instant agrees.

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Inspiration

A deadline can look precise while still being impossible to trust. A rules page says 11:59 PM Pacific; a submission portal shows a different UTC cutoff. A clock-change night can even make one local time mean two different instants. A normal calendar entry hides those disagreements.

Cutoff makes uncertainty visible before it becomes a confident reminder. It is a focused workbench for students and anyone comparing deadline statements across sources and time zones.

What it does

Enter each source's exact wording, link, and structured date, time and time zone. Cutoff keeps the original statement separate from your explicit clarification, compares the resulting instants, and shows them on one timeline.

  • Flags missing time zones, daylight-saving gaps and repeated hours, weekday contradictions, and conflicting deadlines.
  • Requires an explicit interpretation when a local time is ambiguous instead of silently choosing one.
  • Shows a conservative personal planning target only when every source has an exact interpretation.
  • Unlocks calendar export only when every entered source resolves to the same instant. Agreement validates the conversion, not the source's authority.
  • Preserves source quotes, links and clarification notes in the exported .ics file.

The calendar export is a tentative, transparent, one-minute personal planning marker with no automatic alarm. It is not an official deadline.

How I built it

Cutoff was developed for Next Byte Hacks V5 during its October 2026 build window. It is a solo, local-first JavaScript web application with HTML and CSS, using the Temporal polyfill for explicit time-zone interpretation and esbuild for production assets. The public repository includes setup instructions, tests, MIT licensing and third-party notices.

The interface moves from evidence to interpretation to action: enter the sources, see the uncertainty, then plan. Responsive layouts, keyboard-focused dialogs and reduced-motion support are part of that flow. No account, paid API or runtime AI service is needed.

Challenges

The hardest part was not displaying another time zone. It was refusing to invent certainty. A nonexistent local time must not be shifted silently; a repeated hour must not default invisibly to one occurrence; a planning buffer must not turn conflicting sources into an exportable official deadline.

Another practical challenge was browser storage. A stale tab now detects a changed saved workspace before an ordinary write, preserves its in-memory edits, and offers a deliberate reload or fresh start rather than silently overwriting the newer saved data. This compare-before-write protection is not an atomic multi-user synchronization system.

Accomplishments

The current implementation has passed 85 Node tests and 18 hosted Chromium browser-check groups, including storage conflict handling, clarification flows and calendar download. Earlier documented verification also covers responsive layouts and independent calendar parsing. These are development checks, not a full accessibility certification or a claim of compatibility with every browser or calendar provider.

The most important result is a working product that can say "not yet": unresolved evidence blocks a target, and disagreement blocks calendar export. Six built-in synthetic cases let visitors try the edge cases immediately.

What I learned

Trustworthy planning tools need to preserve the distinction between a source statement, a user's interpretation and a computed result. Showing why an action is unavailable can be more useful than making every button work immediately.

What's next

Test the workflow with students comparing real deadlines, improve the clarification language from that feedback, and validate calendar imports across providers. Those are future plans; no real-user study or measured productivity benefit is claimed.

Transparency and limits

AI assisted implementation, test preparation and writing. Open-source runtime dependencies include @js-temporal/polyfill and jsbi; their licenses are disclosed in the repository. All bundled examples and test fixtures are synthetic.

Cutoff does not fetch source websites, parse quotes, verify transcription or decide which source is authoritative. Confirm consequential deadlines with the organizer. Workspace data stays in this browser's local storage, which is not encrypted, backed up or synchronized. Exported files contain the entered evidence; importing them into a cloud calendar may share that evidence with the provider.

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