diff --git a/.jules/sentinel.md b/.jules/sentinel.md
new file mode 100644
index 0000000..621b011
--- /dev/null
+++ b/.jules/sentinel.md
@@ -0,0 +1,4 @@
+## 2025-02-28 - Caddy HTTP Security Headers Configuration
+**Vulnerability:** The application was missing basic security headers (X-Frame-Options, X-Content-Type-Options, Referrer-Policy), increasing exposure to clickjacking and MIME-sniffing attacks.
+**Learning:** Security posture isn't just about application-level code. The reverse proxy (Caddy) configuration serves as the first line of defense and is the correct layer to enforce global HTTP response headers.
+**Prevention:** Always verify that the reverse proxy layer enforces foundational HTTP security headers instead of relying solely on the application code to handle response security.
diff --git a/Caddyfile b/Caddyfile
index 5cd8f6d..cdb0256 100644
--- a/Caddyfile
+++ b/Caddyfile
@@ -6,6 +6,12 @@
 :80 {
   encode zstd gzip
 
+  header {
+    X-Frame-Options "DENY"
+    X-Content-Type-Options "nosniff"
+    Referrer-Policy "strict-origin-when-cross-origin"
+  }
+
   handle /mcp {
     reverse_proxy 127.0.0.1:3001
   }