OpenAI added an iCloud Calendar connection to ChatGPT on 27 October 2026. When asking an assistant to prepare calendar entries, state whether each item lasts all day. The iCalendar example below concerns an exported file; it does not describe the connection’s internal protocol or promise that every event action is available.
An all-day event in an iCalendar file uses dates rather than a midnight appointment with an arbitrary time zone. Under RFC 5545, a VEVENT end date is exclusive: it is the first date outside the event.
Check a one-day example
For an event on November 5, 2026, the relevant lines are:
DTSTART;VALUE=DATE:20261105DTEND;VALUE=DATE:20261106
These are an excerpt, not a complete importable calendar file. Ask the AI for a complete calendar with the required event identifiers and timestamps, preserving the date-only values. Do not change both dates to November 5 or add a time-zone parameter just to make the file look more detailed.
Import into a test calendar
Check that the event occupies only November 5 in day and month views. Confirm its title and verify that repeating an import will not create an unwanted duplicate. Keep the original file and test separately from your main calendar. Correct-looking source text alone does not prove the importer interpreted the event correctly.
For a two-day event covering 5 and 6 November, the end would instead be 7 November. Check the displayed dates after import, then remove the test entry if it is no longer needed. If the assistant edits a connected calendar directly, verify the resulting entry in that calendar rather than assuming that a successful tool message proves its dates.