Cronlab

A scheduled task manager for macOS.
Built to automate Claude Code sessions via launchd.

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Why Cronlab?

cron on macOS cannot access the Keychain. As a result, commands like claude -p "..." fail with Not logged in.

Cronlab uses launchd (the native macOS scheduler) which runs in the user context with full access to the Keychain, Homebrew PATH, and shell environment.

crontab  -->  no Keychain access  -->  "Not logged in"
launchd  -->  Keychain access     -->  Claude runs fine

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Features

Feature	Description
View	List all tasks with active/inactive status, cron schedule, command
Create	Form with individual cron fields, quick presets, live preview
Edit	Inline editing of each task (schedule, command, label)
Enable/Disable	Toggle on/off without deleting the task
Delete	Double confirmation before removal
History	Stdout/stderr logs from each execution

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Screenshots

Task list

Main view with tasks showing active/inactive states, cron schedules, and commands.

Create form

Live cron expression preview, 9 quick presets, command and label fields.

Inline edit mode

Click the pencil icon to edit the schedule, command, and label directly in the card.

Execution history

View stdout/stderr logs from each task execution.

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Installation

Prerequisites

• macOS (uses launchd)
• Node.js 20+
• Claude Code installed (optional, for automated sessions)

Setup

# Clone the repo
git clone https://github.com/Refaltor77/Cronlab.git
cd Cronlab

# Install dependencies
npm install

# Start the server
npm run dev

Open http://localhost:3000.

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Architecture

src/
  app/
    page.tsx                         # Main interface (React client component)
    layout.tsx                       # Layout with Geist font
    globals.css                      # Design system (white theme)
    api/
      crontab/
        route.ts                     # LaunchAgents CRUD (GET/POST/PUT/PATCH/DELETE)
        history/
          route.ts                   # Execution logs reader

~/Library/LaunchAgents/
  com.cronlab.task-*.plist           # Plist files generated by Cronlab

~/.cronlab/logs/
  task-*.stdout.log                  # Standard output for each task
  task-*.stderr.log                  # Error output for each task
  task-*.meta.json                   # Metadata (label)

How it works

1. Create — Cronlab generates a .plist file in ~/Library/LaunchAgents/
2. Load — launchctl load registers the plist with the macOS scheduler
3. Execute — launchd runs the command via /bin/zsh -l -c (login shell = Keychain access)
4. Log — stdout/stderr are redirected to ~/.cronlab/logs/
5. Disable — launchctl unload removes the job without deleting the file

Generated plist example

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>
    <key>Label</key>
    <string>com.cronlab.task-1234567890</string>
    <key>ProgramArguments</key>
    <array>
      <string>/bin/zsh</string>
      <string>-l</string>
      <string>-c</string>
      <string>claude -p "Review open PRs" --dangerously-skip-permissions</string>
    </array>
    <key>StartCalendarInterval</key>
    <dict>
      <key>Hour</key>
      <integer>9</integer>
      <key>Minute</key>
      <integer>0</integer>
    </dict>
    <key>StandardOutPath</key>
    <string>~/.cronlab/logs/task-1234567890.stdout.log</string>
    <key>StandardErrorPath</key>
    <string>~/.cronlab/logs/task-1234567890.stderr.log</string>
  </dict>
</plist>

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Usage examples

Daily code review every morning

Schedule :  0 9 * * 1-5
Command  :  claude -p "Review open PRs on this repo and summarize the changes" --dangerously-skip-permissions
Label    :  Daily Code Review

Health check every 15 minutes

Schedule :  */15 * * * *
Command  :  claude -p "Run the tests and verify the build passes" --dangerously-skip-permissions
Label    :  Health Check CI

Weekly report on Sundays

Schedule :  0 0 * * 0
Command  :  claude -p "Generate a summary of this week's commits" --dangerously-skip-permissions
Label    :  Weekly Report

Daily backup at midnight

Schedule :  0 0 * * *
Command  :  tar -czf ~/backups/project-$(date +%Y%m%d).tar.gz ~/my-project
Label    :  Project Backup

Log cleanup every Monday

Schedule :  0 6 * * 1
Command  :  find ~/.cronlab/logs -name "*.log" -mtime +30 -delete
Label    :  Log Cleanup

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Cron expressions

Cronlab uses the standard 5-field cron syntax:

*    *    *    *    *
|    |    |    |    |
|    |    |    |    +-- Day of week (0-6, 0 = Sunday)
|    |    |    +------- Month (1-12)
|    |    +------------ Day of month (1-31)
|    +----------------- Hour (0-23)
+---------------------- Minute (0-59)

Available presets

Preset	Expression	Use case
Every minute	* * * * *	Testing and debug
Every 5 min	*/5 * * * *	Frequent monitoring
Every 15 min	*/15 * * * *	Health checks
Every hour	0 * * * *	Hourly tasks
Every day 9 AM	0 9 * * *	Daily standup
Every day midnight	0 0 * * *	Nightly maintenance
Mon-Fri 9 AM	0 9 * * 1-5	Weekdays only
Every Sunday	0 0 * * 0	Weekly reports
1st of month	0 0 1 * *	Monthly reports

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API

All routes are under /api/crontab.

Method	Endpoint	Description
GET	/api/crontab	List all tasks
POST	/api/crontab	Create a new task
PUT	/api/crontab	Update an existing task
PATCH	/api/crontab	Enable/disable a task
DELETE	/api/crontab	Delete a task
GET	/api/crontab/history	Execution history

curl examples

# List tasks
curl http://localhost:3000/api/crontab

# Create a task
curl -X POST http://localhost:3000/api/crontab \
  -H "Content-Type: application/json" \
  -d '{
    "schedule": "0 9 * * 1-5",
    "command": "claude -p \"Review open PRs\" --dangerously-skip-permissions",
    "comment": "Daily Code Review"
  }'

# Disable a task
curl -X PATCH http://localhost:3000/api/crontab \
  -H "Content-Type: application/json" \
  -d '{"id": "task-123", "enabled": false}'

# Update a task
curl -X PUT http://localhost:3000/api/crontab \
  -H "Content-Type: application/json" \
  -d '{
    "id": "task-123",
    "schedule": "0 10 * * 1-5",
    "command": "claude -p \"New prompt\" --dangerously-skip-permissions",
    "comment": "Updated label"
  }'

# Delete a task
curl -X DELETE http://localhost:3000/api/crontab \
  -H "Content-Type: application/json" \
  -d '{"id": "task-123"}'

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Tech stack

Component	Technology
Framework	Next.js 16 (App Router)
UI	React 19, Tailwind CSS 4
Font	Geist Sans + Geist Mono
Scheduler	macOS launchd
Plist	simple-plist
Runtime	Node.js

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Debugging

Check active LaunchAgents

launchctl list | grep cronlab

View job logs

cat ~/.cronlab/logs/task-XXXX.stdout.log
cat ~/.cronlab/logs/task-XXXX.stderr.log

List plist files

ls ~/Library/LaunchAgents/com.cronlab.*

Force reload a job

launchctl unload ~/Library/LaunchAgents/com.cronlab.task-XXXX.plist
launchctl load ~/Library/LaunchAgents/com.cronlab.task-XXXX.plist

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License

MIT