Auto-Schedule Weekly Focus-Time Blocks: Google Calendar + OpenAI + Slack

Input next week's calendar events → calculate weekday free gaps → auto-book Focus Time and generate a Slack deep-work plan

Who

Knowledge workers who need to protect deep-work time in their schedules

You get

Every Sunday at 18:00, scan next week's calendar, book 2+ hour free gaps as Focus Time, and receive a personalized Slack deep-work plan or fragmentation warning

You need

n8n · google-calendar · slack

Steps

1. Configure trigger and preferences

   Import the template into n8n. Check the 'Every Sunday 18:00' trigger node (Schedule Trigger) and confirm the rule fires weekly on Sundays at 18:00. Open the '⚙️ My Preferences' node and modify: workStartHour (default 9), workEndHour (default 18), minBlockHours (default 2), maxBlocksPerWeek (default 5).

2. Connect Google Calendar and fetch next week's events

   Add Google Calendar credentials. In the 'Get Next Week's Events' node, select the calendar to read from (mode: list), set operation to getAll, and enable returnAll. This node pulls all events for the coming week to feed the gap calculation.

3. Run code to compute weekday free gaps

   The 'Find Free Gaps' node executes JavaScript: reads preferences from ⚙️ My Preferences; filters events with start.dateTime and status not cancelled; scans Monday–Friday only (skips weekends); calculates gaps between events within workStartHour–workEndHour; keeps gaps ≥ minBlockHours, capped at 3 hours each; outputs objects with found, start, end, durationHours, weekday. If no gap qualifies, returns {found: false}.

   Execution prompt · Source text。Code node parameter in 'Find Free Gaps'

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   // Find free gaps of at least `minBlockHours` inside working hours, Monday–Friday
   const prefs = $('⚙️ My Preferences').first().json;
   const events = $input.all()
     .map(i => i.json)
     .filter(e => e.start?.dateTime && e.status !== 'cancelled')
     .map(e => ({ start: new Date(e.start.dateTime), end: new Date(e.end.dateTime) }))
     .sort((a, b) => a.start - b.start);
   
   const gaps = [];
   const now = new Date();
   
   for (let d = 1; d <= 6; d++) {
     const day = new Date(now);
     day.setDate(now.getDate() + d);
     const dow = day.getDay();
     if (dow === 0 || dow === 6) continue; // weekdays only
   
     const dayStart = new Date(day); dayStart.setHours(prefs.workStartHour, 0, 0, 0);
     const dayEnd = new Date(day); dayEnd.setHours(prefs.workEndHour, 0, 0, 0);
   
     const dayEvents = events.filter(e => e.start < dayEnd && e.end > dayStart);
     let cursor = dayStart;
   
     for (const e of [...dayEvents, { start: dayEnd, end: dayEnd }]) {
       const gapHours = (e.start - cursor) / 36e5;
       if (gapHours >= prefs.minBlockHours) {
         gaps.push({
           found: true,
           start: cursor.toISOString(),
           end: new Date(Math.min(e.start, cursor.getTime() + 3 * 36e5)).toISOString(),
           durationHours: Number(Math.min(gapHours, 3).toFixed(1)),
           weekday: day.toLocaleDateString('en-US', { weekday: 'long' })
         });
       }
       if (e.end > cursor) cursor = e.end;
     }
   }
   
   if (gaps.length === 0) {
     return [{ json: { found: false } }];
   }
   
   return gaps.map(g => ({ json: g }));

4. Branch: check for available slots

   The 'Any Focus Slots?' node (If) checks whether $json.found is true. If gaps exist, flow continues to 'Cap Blocks Per Week'; otherwise it routes to 'Warn: Week Too Fragmented' to send the fragmentation warning.

5. Cap weekly blocks and write to calendar

   'Cap Blocks Per Week' (Limit node) restricts the number of gaps to maxBlocksPerWeek. Then 'Book Focus Block' (Google Calendar) creates an event for each approved gap: summary '🧘 Focus Time (protected by n8n)', color 9, description notes auto-booking and advises declining conflicting meetings. start and end use the gap ISO strings. Select the target calendar to write into.

6. Aggregate booked blocks and generate deep-work plan

   'Bundle Booked Blocks' (Aggregate) collects all booked slots into a blocks field. 'Write My Focus Plan' (Basic LLM Chain) calls the OpenAI Chat Model (gpt-4o-mini) with system message 'You are a supportive productivity coach who specializes in deep work.' and a user prompt that includes the booked blocks JSON, requesting a ≤180-word Slack message: list each block (weekday + time range), suggest work type per slot (long → hard creative, shorter → reviews/writing), and one practical tip to defend blocks from meeting requests. Slack formatting, personal tone.

   Execution prompt · Source text。messages.messageValues[0].message in 'Write My Focus Plan' (system message)

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   You are a supportive productivity coach who specializes in deep work.

   Execution prompt · Source text。text parameter in 'Write My Focus Plan' (user prompt)

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   =I just protected these deep-work blocks in my calendar for next week:
   
   {{ JSON.stringify($('Cap Blocks Per Week').all().map(i => i.json), null, 2) }}
   
   Write me a short, motivating Slack message (max 180 words):
   1. List each block (weekday + time range, human-readable)
   2. Suggest what type of work fits each slot (long blocks → hard creative work, shorter → reviews/writing)
   3. One practical tip to actually defend these blocks from meeting requests
   
   Use Slack formatting and keep it personal — this goes to one person, not a team.

7. Send Slack deep-work plan or fragmentation warning

   If slots exist, 'DM My Focus Plan' sends the generated message to the configured Slack user as '🧘 *Your deep-work plan for next week*\n\n{{ $json.text }}'. If no slots exist, 'Warn: Week Too Fragmented' sends: '⚠️ *Focus Time Defender*: I couldn't find a single free 2-hour slot in your working hours next week. Your calendar is fully fragmented — consider declining or shortening some meetings, then re-run me.' Both Slack nodes use user.mode=username; replace 'your-slack-handle' with the actual username.

   Execution prompt · Source text。text parameter in 'DM My Focus Plan'

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   =🧘 *Your deep-work plan for next week*
   
   {{ $json.text }}

   Execution prompt · Source text。text parameter in 'Warn: Week Too Fragmented'

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   ⚠️ *Focus Time Defender*: I couldn't find a single free 2-hour slot in your working hours next week. Your calendar is fully fragmented — consider declining or shortening some meetings, then re-run me.

Import the template at https://n8n.io/workflows/17074/ into n8n, configure credentials, preferences, and Slack username as described above, then activate. To adjust the LLM output style, edit the system message and user prompt in the 'Write My Focus Plan' node.