List family members. Use the id for appointment attendees. Returns: [{id, name, color?}].

Summarize all lists (no items). Optionally filter by 'shopping' or 'todo'. Returns: [{id, title, type, item_count, completed_count}].

Items in one list. Excludes completed items by default. Returns: [{id, text, status, position?}].

Create a list ('shopping' or 'todo'). Returns: {id, title, type}.

Delete a list. Returns true on success.

Add an item to a list. Returns: {id, text}.

Update an item's text and/or completion status. Pass text, completed, or both. When both are provided the text is updated first then status is updated as a separate request — these are NOT atomic. Returns: {id, text, status}.

Remove items from a list. Returns true on success.

Appointments for one month. Returns: [{id, subject, day, all_day, start?, end?, end_day?, attendees?, location?, notes?}]. day is always the start day and end_day appears only on multi-day events; such an event is listed in every month it overlaps, so day may fall outside the month asked for.

Create a calendar appointment. start and end are ISO datetimes (e.g. '2026-06-15T10:00:00'). For all-day events (all_day=true) a bare date (e.g. '2026-06-15') is also accepted and end may equal start; a bare date on a timed event is an error. For a multi-day event put end on a later date — the span is preserved, and the result reports it as end_day. end before start is an error. For attendees, call family_members() first and pass those id values.

Partial-update an appointment. The Cozi PUT semantics replace ALL fields, so this tool first fetches the existing appointment from the (year, month) page and merges your changes — only fields you pass are altered. To switch a timed appointment to all-day pass all_day=true; to switch to timed pass new start/end. Passing end re-spans the event against its (possibly newly set) start day, so an end on a later date makes it multi-day and one on the start day collapses it back; passing start alone moves the event and keeps its length, and all_day=true preserves the span. A bare date (e.g. '2026-06-15') is accepted for start/end when the event is, or is being made, all-day; on a timed event it is an error.

Delete an appointment. Returns true on success.