diff --git a/.gitignore b/.gitignore
index baf1031..a76d5ea 100644
--- a/.gitignore
+++ b/.gitignore
@@ -42,3 +42,8 @@ Desktop.ini
 *.temp
 *.swp
 *~
+
+# Server deployment state
+/.deploy.lock
+/current
+/releases/
diff --git a/DEPLOYMENT.md b/DEPLOYMENT.md
index f0229a3..16f1f9f 100644
--- a/DEPLOYMENT.md
+++ b/DEPLOYMENT.md
@@ -9,6 +9,9 @@ Release manifests are stored in `<DEPLOY_PATH>/releases/<commit-sha>`. Each
 manifest records the immutable image tag and Gitea run number. The `current`
 symlink is changed only after the new container is healthy. If startup fails,
 the deployment script restarts the previous image without rebuilding it.
+After health succeeds, the Git checkout at `<DEPLOY_PATH>` is fast-forwarded to
+the exact deployed commit. Deployment refuses to overwrite tracked server-side
+changes or a checkout that has diverged from `origin/main`.
 
 ## Gitea Actions setup
 
diff --git a/scripts/deploy-release.sh b/scripts/deploy-release.sh
index 89a43be..ea12c31 100644
--- a/scripts/deploy-release.sh
+++ b/scripts/deploy-release.sh
@@ -49,6 +49,40 @@ mkdir -p -- "$releases_dir"
 exec 9>"$deploy_root/.deploy.lock"
 flock -x 9
 
+sync_checkout() {
+  local branch remote_release
+
+  if [[ ! -d "$deploy_root/.git" ]]; then
+    echo "Deployment root is not a Git checkout: $deploy_root" >&2
+    return 1
+  fi
+  if ! git -C "$deploy_root" diff --quiet --ignore-submodules -- \
+    || ! git -C "$deploy_root" diff --cached --quiet --ignore-submodules --; then
+    echo "Refusing to update a checkout with tracked changes: $deploy_root" >&2
+    return 1
+  fi
+
+  branch="$(git -C "$deploy_root" symbolic-ref --quiet --short HEAD || true)"
+  if [[ "$branch" != "main" ]]; then
+    echo "Deployment checkout must be on main, not ${branch:-detached HEAD}." >&2
+    return 1
+  fi
+
+  git -C "$deploy_root" fetch --quiet \
+    origin "+refs/heads/main:refs/remotes/origin/main"
+  remote_release="$(git -C "$deploy_root" rev-parse refs/remotes/origin/main)"
+  if [[ "$remote_release" != "$release_id" ]]; then
+    echo "origin/main is $remote_release, expected deployed release $release_id." >&2
+    return 1
+  fi
+
+  git -C "$deploy_root" merge --ff-only --quiet refs/remotes/origin/main
+  if [[ "$(git -C "$deploy_root" rev-parse HEAD)" != "$release_id" ]]; then
+    echo "Checkout did not advance to deployed release $release_id." >&2
+    return 1
+  fi
+}
+
 if ! docker image inspect "$image" >/dev/null 2>&1; then
   echo "Verified runtime image is missing from the production Docker daemon: $image" >&2
   exit 1
@@ -63,7 +97,8 @@ if [[ -n "$previous_release" && -f "$previous_release/release.env" ]]; then
   current_sequence="$(sed -n 's/^DEPLOY_SEQUENCE=//p' "$previous_release/release.env")"
   current_release="$(basename "$previous_release")"
   if [[ "$current_release" == "$release_id" ]]; then
-    echo "Release is already active: $release_id"
+    sync_checkout
+    echo "Release and server checkout are already active: $release_id"
     exit 0
   fi
   if [[ "$current_sequence" =~ ^[1-9][0-9]*$ ]] && (( sequence <= current_sequence )); then
@@ -144,6 +179,10 @@ if activate "$release_dir"; then
   new_link="$deploy_root/.current-$release_id-$$"
   ln -s -- "$release_dir" "$new_link"
   mv -Tf -- "$new_link" "$current_link"
+  if ! sync_checkout; then
+    echo "Deployment is healthy, but the server checkout could not be updated." >&2
+    exit 1
+  fi
   echo "Deployment succeeded: $release_id ($image)"
   exit 0
 fi