Claude code session memory hook

.claude hooks session-end-memory.sh

#!/bin/bash
# Auto-save session learnings to memory on exit

LOG="$HOME/.claude/hooks/session-end-memory.log"

log() { echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*" >> "$LOG"; }

# Loop prevention — child claude -p session also triggers SessionEnd
LOCK="/tmp/claude-memory-save.lock"
if [ -f "$LOCK" ]; then
  PID=$(cat "$LOCK")
  if kill -0 "$PID" 2>/dev/null; then
    log "Skipping — memory save already running (PID $PID)"
    exit 0
  else
    log "Removing stale lock (PID $PID no longer running)"
    rm -f "$LOCK"
  fi
fi
echo $$ > "$LOCK"
trap "rm -f $LOCK" EXIT

# Only fire on explicit /exit
HOOK_INPUT=$(cat)
REASON=$(jq -r '.reason' <<< "$HOOK_INPUT")
if [ "$REASON" != "prompt_input_exit" ]; then
  log "Skipping — reason was '$REASON', not prompt_input_exit"
  exit 0
fi

TRANSCRIPT=$(jq -r '.transcript_path' <<< "$HOOK_INPUT")

# Derive memory dir from git root — mirrors Claude's path escaping (/ → -)
PROJECT_ROOT=$(git rev-parse --show-toplevel 2>/dev/null || pwd)
ESCAPED=$(echo "$PROJECT_ROOT" | sed 's|/|-|g')
MEMORY_DIR="$HOME/.claude/projects/$ESCAPED/memory"

if [ ! -d "$MEMORY_DIR" ]; then
  log "Skipping — no memory dir at $MEMORY_DIR"
  exit 0
fi

log "Running memory save for $MEMORY_DIR (transcript: $TRANSCRIPT)"

# Pre-extract text content from transcript to avoid token overload when reading raw JSONL.
# Pulls assistant text + user text, truncates to ~8000 chars, saves to a temp summary file.
SUMMARY_FILE=$(mktemp /tmp/claude-session-summary.XXXXXX)
python3 - "$TRANSCRIPT" "$SUMMARY_FILE" <<'PYEOF'
import sys, json

transcript_path = sys.argv[1]
output_path = sys.argv[2]
MAX_CHARS = 8000
chunks = []

with open(transcript_path) as f:
    for line in f:
        line = line.strip()
        if not line:
            continue
        try:
            obj = json.loads(line)
        except json.JSONDecodeError:
            continue
        role = obj.get("role", "")
        if role not in ("user", "assistant"):
            continue
        content = obj.get("content", "")
        texts = []
        if isinstance(content, list):
            for block in content:
                if isinstance(block, dict) and block.get("type") == "text":
                    texts.append(block["text"])
        elif isinstance(content, str):
            texts.append(content)
        for text in texts:
            text = text.strip()
            if text:
                chunks.append(f"[{role}]: {text}")

full = "\n---\n".join(chunks)
if len(full) > MAX_CHARS:
    full = full[:MAX_CHARS] + "\n...[truncated]"

with open(output_path, "w") as f:
    f.write(full)
PYEOF

trap "rm -f $LOCK $SUMMARY_FILE" EXIT

claude -p "Review the following session summary and save any useful patterns, tool learnings, architectural insights, or user preferences to $MEMORY_DIR. Update MEMORY.md if needed and create or update topic files for detailed notes. Be concise and avoid duplicating existing entries.

<session_summary>
$(cat "$SUMMARY_FILE")
</session_summary>" \
  --allowedTools "Read,Write,Edit,Glob"

~ .claude settings.json

{
  "$schema": "https://json.schemastore.org/claude-code-settings.json",
  "hooks": {
    "SessionEnd": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "~/.claude/hooks/session-end-memory.sh",
            "statusMessage": "Saving session memories..."
          }
        ]
      }
    ]
  }
}