Obsidian MCP Server

Instructions

Implementation Reference

• src/obsidian_mcp/server.py:1213-1342 (handler)

  MCP tool handler for update_calendar_event: orchestrates event retrieval, parameter parsing, calls CalendarService.update_event, updates linked Obsidian note frontmatter, and preserves Obsidian links in descriptions.

      name="update_calendar_event",
      description="Update/move a calendar event (change date, time, title, or description)",
  )
  async def update_calendar_event(
      event_id: str,
      title: str = "",
      date: str = "",
      time: str = "",
      duration_minutes: int = 0,
      description: str = "",
      location: str = "",
      confirm: bool = False,
  ) -> str:
      """
      Update a calendar event.
  
      Args:
          event_id: Calendar event ID to update
          title: New event title (optional)
          date: New date YYYY-MM-DD (optional)
          time: New time HH:MM (optional)
          duration_minutes: New duration in minutes (optional)
          description: New description (optional)
          location: New location (optional)
          confirm: Must be set to true to confirm event update
  
      Returns:
          Success message with updated details
      """
      if not confirm:
          return (
              "Error: Calendar event update requires explicit confirmation. "
              "Please set confirm=true to proceed with updating this event."
          )
      if not event_id or not event_id.strip():
          return "Error: Event ID cannot be empty"
  
      context = _get_context()
  
      try:
          calendar = context.get_calendar()
  
          # Get current event to preserve existing values
          current_event = calendar.get_event(event_id)
  
          # Parse new date/time if provided
          new_start = None
          new_end = None
          if date and time:
              try:
                  event_datetime = datetime.strptime(f"{date} {time}", "%Y-%m-%d %H:%M")
                  if duration_minutes > 0:
                      new_end = event_datetime + timedelta(minutes=duration_minutes)
                  else:
                      # Preserve original duration
                      current_start = current_event.get("start", {})
                      current_end = current_event.get("end", {})
                      if "dateTime" in current_start and "dateTime" in current_end:
                          old_start = datetime.fromisoformat(
                              current_start["dateTime"].replace("Z", "+00:00")
                          )
                          old_end = datetime.fromisoformat(
                              current_end["dateTime"].replace("Z", "+00:00")
                          )
                          duration = (old_end - old_start).seconds // 60
                          new_end = event_datetime + timedelta(minutes=duration)
                  new_start = event_datetime
              except ValueError as e:
                  return f"Error: Invalid date/time format: {e}. Use YYYY-MM-DD and HH:MM"
  
          # Prepare update - preserve obsidian:// link if in description
          new_description = None
          if description:
              current_desc = current_event.get("description", "")
              # Check if there's an obsidian link to preserve
              if context.config.obsidian_url_base in current_desc:
                  link_start = current_desc.find(context.config.obsidian_url_base)
                  link_end = current_desc.find("\n", link_start)
                  if link_end == -1:
                      link_end = len(current_desc)
                  obsidian_link = current_desc[link_start:link_end].strip()
                  new_description = f"{description}\n\n{obsidian_link}"
              else:
                  new_description = description
  
          # Update event
          updated_event = calendar.update_event(
              event_id=event_id,
              summary=title if title else None,
              start_datetime=new_start,
              end_datetime=new_end,
              description=new_description,
              location=location if location else None,
          )
  
          # Update note frontmatter if date changed and we can find the linked note
          if new_start:
              current_desc = current_event.get("description", "")
              if context.config.obsidian_url_base in current_desc:
                  link_start = current_desc.find(context.config.obsidian_url_base)
                  note_path = current_desc[link_start + len(context.config.obsidian_url_base) :]
                  note_path = note_path.split()[0] if note_path else ""
  
                  if note_path and context.vault.note_exists(note_path):
                      note = await context.vault.read_note(note_path)
                      if note.frontmatter and "calendar_event_id" in note.frontmatter:
                          await context.vault.update_frontmatter(
                              note_path,
                              {
                                  "calendar_event_date": new_start.strftime("%Y-%m-%d"),
                                  "calendar_event_time": new_start.strftime("%H:%M"),
                              },
                          )
  
          result = ["✅ Calendar event updated!"]
          result.append(f"Event: {updated_event.get('summary', 'Untitled')}")
          result.append(f"Link: {updated_event.get('htmlLink')}")
  
          if new_start:
              result.append(f"New time: {new_start.strftime('%Y-%m-%d %H:%M')}")
  
          return "\n".join(result)
  
      except CalendarError as e:
          logger.exception("Error updating calendar event")
          return f"Error: {e}"
      except Exception as e:
          logger.exception("Error updating calendar event")
          return f"Error updating calendar event: {e}"

• src/obsidian_mcp/calendar.py:218-278 (helper)

  Core implementation in CalendarService: fetches existing event via Google Calendar API, applies provided updates to summary, times, description, location, and executes the update.

  def update_event(
      self,
      event_id: str,
      summary: str | None = None,
      start_datetime: datetime | None = None,
      end_datetime: datetime | None = None,
      description: str | None = None,
      location: str | None = None,
  ) -> dict[str, Any]:
      """
      Update an existing calendar event.
  
      Args:
          event_id: Event ID to update
          summary: New event title
          start_datetime: New start time
          end_datetime: New end time
          description: New description
          location: New location
  
      Returns:
          Updated event details
  
      Raises:
          CalendarError: If update fails
      """
      service = self.get_service()
  
      try:
          # Get existing event
          event = service.events().get(calendarId=self.calendar_id, eventId=event_id).execute()
  
          # Update fields
          if summary is not None:
              event["summary"] = summary
          if start_datetime is not None:
              event["start"] = {
                  "dateTime": start_datetime.isoformat(),
                  "timeZone": "UTC",
              }
          if end_datetime is not None:
              event["end"] = {
                  "dateTime": end_datetime.isoformat(),
                  "timeZone": "UTC",
              }
          if description is not None:
              event["description"] = description
          if location is not None:
              event["location"] = location
  
          # Update event
          updated_event = (
              service.events()
              .update(calendarId=self.calendar_id, eventId=event_id, body=event)
              .execute()
          )
          logger.info(f"Updated calendar event: {event_id}")
          return updated_event  # type: ignore[no-any-return]
      except HttpError as e:
          raise CalendarError(f"Failed to update event: {e}") from e

• src/obsidian_mcp/server.py:1213-1216 (registration)

  MCP tool registration decorator specifying the tool name and description.

      name="update_calendar_event",
      description="Update/move a calendar event (change date, time, title, or description)",
  )
  async def update_calendar_event(