Auto-Save Hooks

Two hooks for Claude Code and Codex that automatically save memories during work. No manual "save" commands needed.

What They Do

Hook	When It Fires	What Happens
Save Hook	Every 15 human messages	Blocks the AI, tells it to save key topics/decisions/quotes to the palace
PreCompact Hook	Right before context compaction	Emergency save — forces the AI to save everything before losing context

The AI does the actual filing — it knows the conversation context, so it classifies memories into the right wings/halls/closets. The hooks just tell it when to save.

Install — Claude Code

Add to .claude/settings.local.json:

{
  "hooks": {
    "Stop": [{
      "matcher": "*",
      "hooks": [{
        "type": "command",
        "command": "/absolute/path/to/hooks/mempal_save_hook.sh",
        "timeout": 30
      }]
    }],
    "PreCompact": [{
      "hooks": [{
        "type": "command",
        "command": "/absolute/path/to/hooks/mempal_precompact_hook.sh",
        "timeout": 30
      }]
    }]
  }
}

Make them executable:

chmod +x hooks/mempal_save_hook.sh hooks/mempal_precompact_hook.sh

Install — Codex CLI

Add to .codex/hooks.json:

{
  "Stop": [{
    "type": "command",
    "command": "/absolute/path/to/hooks/mempal_save_hook.sh",
    "timeout": 30
  }],
  "PreCompact": [{
    "type": "command",
    "command": "/absolute/path/to/hooks/mempal_precompact_hook.sh",
    "timeout": 30
  }]
}

Configuration

Edit mempal_save_hook.sh to change:

• SAVE_INTERVAL=15 — How many messages between saves. Lower = more frequent, higher = less interruption.
• STATE_DIR — Where hook state is stored (defaults to ~/.mempalace/hook_state/)
• MEMPAL_DIR — Optional. Set to a conversations directory to auto-run mempalace mine on each save trigger.

How It Works

Save Hook (Stop event)

User sends message → AI responds → Stop hook fires
                                          ↓
                                  Count human messages in transcript
                                          ↓
                            ┌── < 15 since last save → let AI stop
                            │
                            └── ≥ 15 since last save → block + save
                                                            ↓
                                                    AI saves to palace
                                                            ↓
                                                    AI stops (flag set)

The stop_hook_active flag prevents infinite loops.

PreCompact Hook

Context window full → PreCompact fires → ALWAYS blocks → AI saves → Compaction proceeds

No counting needed — compaction always warrants a save.

Debugging

cat ~/.mempalace/hook_state/hook.log

Example output:

[14:30:15] Session abc123: 12 exchanges, 12 since last save
[14:35:22] Session abc123: 15 exchanges, 15 since last save
[14:35:22] TRIGGERING SAVE at exchange 15
[14:40:01] Session abc123: 18 exchanges, 3 since last save

Cost

Zero extra tokens. The hooks are bash scripts that run locally. They don't call any API. The only "cost" is a few seconds of the AI organizing memories at each checkpoint.