feat: Overnight Autonomous Research Agent

Overnight Autonomous Research Agent

Overview

Claude Code skill that runs autonomously overnight on a dedicated second computer (Intel i7 MacBook Pro). Takes a research direction, explores broadly, never blocks on questions (logs with best guesses), produces a morning report. Claude Code’s built-in --continue handles crash recovery. A cron wrapper + tmux keeps it running.

Implementation

Phase 1: MVP — 5 files, run it tonight

File	Purpose
`.claude/skills/overnight/SKILL.md`	Agent behavior and exploration loop
`scripts/overnight-launch.sh`	Create workspace, start Claude Code in tmux
`scripts/overnight-restart.sh`	Detect dead session, resume via `--continue`
`scripts/overnight-stop.sh`	Graceful shutdown
`scripts/overnight-status.sh`	One-screen status check

How it works:

Launch script starts Claude Code in a tmux session with --dangerously-skip-permissions
Agent explores the topic, writes findings to findings/, appends questions to questions.md
If the session dies (rate limit, crash, network), cron detects the dead tmux session and restarts via claude --continue
When the agent has explored all branches or time is up, it writes report.md and a DONE sentinel file
Restart wrapper sees DONE or FAILED and stops restarting

Crash recovery: claude --continue resumes the most recent session in the working directory. No custom checkpoint system needed — Claude Code persists sessions to disk natively.

Workspace structure:

~/overnight-runs/2026-03-07-2230/
  CLAUDE.md       ← task briefing + end time (written once at launch, auto-read by Claude)
  questions.md    ← append-only question log
  report.md       ← morning report (written during synthesis = DONE signal)
  FAILED          ← sentinel file if circuit breaker trips
  findings/       ← one .md per exploration branch
  run.log         ← stdout/stderr capture
  restart.log     ← cron restart history

Phase 2: After first successful overnight run

Decide what to build based on what actually broke. Likely candidates:

Iteration mode (answer questions, launch next run)
ntfy.sh phone notifications
Web UI behind Tailscale
Cleanup script for old runs

Second Computer Setup (one-time, ~20 min)

1. Create dedicated user account

sudo dscl . -create /Users/overnight
sudo dscl . -create /Users/overnight UserShell /bin/zsh
sudo dscl . -create /Users/overnight RealName "Overnight Agent"
sudo dscl . -create /Users/overnight UniqueID 550
sudo dscl . -create /Users/overnight PrimaryGroupID 20
sudo dscl . -create /Users/overnight NFSHomeDirectory /Users/overnight
sudo createhomedir -c -u overnight
sudo dscl . -passwd /Users/overnight <password>

2. Prevent sleep + auto-restart after power failure

sudo pmset -c sleep 0 displaysleep 0 disksleep 0
sudo pmset -a disablesleep 1
sudo pmset -c autorestart 1 womp 1

Keep lid open, brightness at zero (clamshell is unreliable without external display).

System Settings > Users & Groups > Login Options > Automatic Login > overnight Disable FileVault (required for auto-login after power failure).

4. Disable auto-updates

sudo defaults write /Library/Preferences/com.apple.SoftwareUpdate AutomaticallyInstallMacOSUpdates -bool false

5. SSH + Tailscale

# Enable SSH: System Settings > General > Sharing > Remote Login > ON
# On your primary computer:
ssh-copy-id overnight@<mac-ip>

# Tailscale for phone access
brew install --cask tailscale
# Install Termius on phone, add Mac's Tailscale IP

6. Install prerequisites (as overnight user)

brew install tmux jq
npm install -g @anthropic-ai/claude-code
claude  # authenticate
mkdir -p ~/overnight-runs ~/scripts

7. Set up cron

crontab -e
# Add:
*/20 * * * * /Users/overnight/scripts/overnight-restart.sh >> /Users/overnight/overnight-cron.log 2>&1