diff --git a/.claude/CLAUDE.md b/.claude/CLAUDE.md
index b669167..3a214e3 100644
--- a/.claude/CLAUDE.md
+++ b/.claude/CLAUDE.md
@@ -61,6 +61,12 @@ Auto-detect on every user message (first match wins):
 
 On mode change: announce `[MODE -> infra]`, tell user to run `/color <color>`. Full details: `.claude/commands/mode.md`
 
+**MANDATORY on every mode change:** write the new mode to `.claude/current-mode` so hooks can read it:
+```bash
+echo dev > .claude/current-mode   # substitute the actual mode name
+```
+This file is gitignored (machine-local). The `UserPromptSubmit` hook reads it to gate the lock check on dev mode.
+
 ---
 
 ## Identity: You Are a Coordinator
diff --git a/.claude/scripts/check-messages.sh b/.claude/scripts/check-messages.sh
index 79c1be3..fce015b 100644
--- a/.claude/scripts/check-messages.sh
+++ b/.claude/scripts/check-messages.sh
@@ -1,26 +1,51 @@
 #!/usr/bin/env bash
-# Checks for unread coord messages and injects them into Claude's context.
-# Runs as a UserPromptSubmit hook — exits silently if no messages or API is down.
+# UserPromptSubmit hook — injects unread coord messages and (in dev mode) active locks.
 SESSION="$(hostname)/claude-main"
 API="http://172.16.3.30:8001"
+SCRIPT_DIR="$(cd "$(dirname "$0")/.." && pwd)"
+MODE_FILE="${SCRIPT_DIR}/current-mode"
+
+# --- Unread messages ---------------------------------------------------------
 
 result=$(curl -s --connect-timeout 3 "${API}/api/coord/messages?to_session=${SESSION}&unread_only=true" 2>/dev/null)
-[ -z "$result" ] && exit 0
 
-count=$(echo "$result" | jq '.total' 2>/dev/null)
-[ -z "$count" ] || [ "$count" -eq 0 ] && exit 0
+if [ -n "$result" ]; then
+  count=$(echo "$result" | jq '.total' 2>/dev/null)
+  if [ -n "$count" ] && [ "$count" -gt 0 ]; then
+    echo ""
+    echo "============================================================"
+    echo "UNREAD COORD MESSAGES ($count)"
+    echo "============================================================"
+    echo "$result" | jq -r '.messages[] | "FROM: \(.from_session)\nDATE: \(.created_at)\nSUBJECT: \(.subject)\n\nMESSAGE:\n\(.body)\n---"'
+    echo "============================================================"
+    echo ""
 
-echo ""
-echo "============================================================"
-echo "UNREAD COORD MESSAGES ($count)"
-echo "============================================================"
-echo "$result" | jq -r '.messages[] | "FROM: \(.from_session)\nDATE: \(.created_at)\nSUBJECT: \(.subject)\n\nMESSAGE:\n\(.body)\n---"'
-echo "============================================================"
-echo ""
+    # Mark all fetched messages as read immediately
+    echo "$result" | jq -r '.messages[].id' | tr -d '\r' | while read -r id; do
+      curl -s -X PUT "${API}/api/coord/messages/${id}/read" >/dev/null 2>&1
+    done
+  fi
+fi
 
-# Mark all fetched messages as read immediately
-echo "$result" | jq -r '.messages[].id' | tr -d '\r' | while read -r id; do
-  curl -s -X PUT "${API}/api/coord/messages/${id}/read" >/dev/null 2>&1
-done
+# --- Active locks (dev mode only) -------------------------------------------
+
+current_mode=""
+[ -f "$MODE_FILE" ] && current_mode=$(cat "$MODE_FILE" | tr -d '[:space:]')
+
+if [ "$current_mode" = "dev" ]; then
+  locks=$(curl -s --connect-timeout 3 "${API}/api/coord/locks" 2>/dev/null)
+  if [ -n "$locks" ]; then
+    lock_count=$(echo "$locks" | jq '.total' 2>/dev/null)
+    if [ -n "$lock_count" ] && [ "$lock_count" -gt 0 ]; then
+      echo ""
+      echo "============================================================"
+      echo "[WARNING] ACTIVE LOCKS ($lock_count) — check before editing"
+      echo "============================================================"
+      echo "$locks" | jq -r '.locks[] | "[DEV MODE] LOCK: \(.project_key) / \(.resource)\n  Held by: \(.session_id)\n  Reason:  \(.description // "none")\n  Expires: \(.expires_at // "unknown")\n---"'
+      echo "============================================================"
+      echo ""
+    fi
+  fi
+fi
 
 exit 0
diff --git a/.gitignore b/.gitignore
index f6f475a..7a6d987 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@ tmp-remediation/
 # Local settings (machine-specific)
 .claude/settings.local.json
 .claude/identity.json
+.claude/current-mode
 
 # Temporary files
 *.tmp