diff --git a/.claude/scripts/update-claude-md.sh b/.claude/scripts/update-claude-md.sh
new file mode 100755
index 0000000..7be6d40
--- /dev/null
+++ b/.claude/scripts/update-claude-md.sh
@@ -0,0 +1,31 @@
+#!/bin/bash
+# Auto-update CLAUDE.md at end of session
+
+CLAUDE_MD="$(git rev-parse --show-toplevel)/CLAUDE.md"
+TIMESTAMP=$(date '+%Y-%m-%d %H:%M')
+
+# Get recent git activity from this session (last hour)
+RECENT_COMMITS=$(git log --oneline --since="1 hour ago" 2>/dev/null | head -5)
+MODIFIED_FILES=$(git diff --name-only HEAD~1 2>/dev/null | head -10)
+
+# Append session summary
+{
+  echo ""
+  echo "### Session: $TIMESTAMP"
+
+  if [ -n "$RECENT_COMMITS" ]; then
+    echo "**Commits:**"
+    echo "\`\`\`"
+    echo "$RECENT_COMMITS"
+    echo "\`\`\`"
+  fi
+
+  if [ -n "$MODIFIED_FILES" ]; then
+    echo "**Modified files:**"
+    echo "$MODIFIED_FILES" | sed 's/^/- /'
+  fi
+
+  echo ""
+} >> "$CLAUDE_MD"
+
+echo "Updated CLAUDE.md with session summary"
diff --git a/CLAUDE.md b/CLAUDE.md
new file mode 100644
index 0000000..8e06638
--- /dev/null
+++ b/CLAUDE.md
@@ -0,0 +1,23 @@
+# VictronBLE Project Context
+
+## Project Overview
+Arduino/ESP32 library for reading Victron Energy devices via Bluetooth Low Energy (BLE).
+
+## Key Files
+- `src/` - Main library source code
+- `examples/` - Example sketches
+- `experiment/` - Experimental code
+- `library.json` / `library.properties` - PlatformIO/Arduino library config
+
+## Build & Test
+- This is an Arduino/PlatformIO library
+- Test with PlatformIO: `pio run`
+
+## Session Notes
+<!-- Add learnings from each session below -->
+
+
+### Session: 2026-01-29 18:41
+**Modified files:**
+- TODO
+