diff --git a/nix/zed-package.nix b/nix/zed-package.nix
index e8d628fb..c8591594 100644
--- a/nix/zed-package.nix
+++ b/nix/zed-package.nix
@@ -179,6 +179,20 @@ rec {
           exit 1
         fi
 
+        # `.zed/operation.lock` is durable mutable-checkout coordination state.
+        # It carries operation/process diagnostics and must never enter a
+        # recursive fixed output. Deterministic adapter-owned state such as
+        # `.zed/node_path` remains in the materialized package tree.
+        operation_lock="$work/.zed/operation.lock"
+        if [[ -e "$operation_lock" ]]; then
+          if [[ -L "$operation_lock" || ! -f "$operation_lock" ]]; then
+            echo "zed-pkg Nix bridge: operation lock is not a regular file" >&2
+            exit 1
+          fi
+          rm -f "$operation_lock"
+          rmdir "$work/.zed" 2>/dev/null || true
+        fi
+
         mkdir -p "$out/tree" "$out/metadata"
         shopt -s dotglob nullglob
         for entry in "$work"/*; do
@@ -314,6 +328,8 @@ rec {
           fi
         done < <(find "$out/tree" -type l -print0)
 
+        test ! -e "$out/tree/.zed/operation.lock"
+
         runHook postInstall
       '';
     };
diff --git a/tests/frozen-lock-integrity-e2e.sh b/tests/frozen-lock-integrity-e2e.sh
index fe4daf41..a1f252d7 100644
--- a/tests/frozen-lock-integrity-e2e.sh
+++ b/tests/frozen-lock-integrity-e2e.sh
@@ -184,7 +184,20 @@ assert_atomic_failure() {
     || fail "$label rewrote its rejected lock"
   [[ ! -e "$root/zed_modules" ]] || fail "$label materialized zed_modules"
   [[ ! -e "$root/node_modules" ]] || fail "$label materialized node_modules"
-  [[ ! -e "$root/.zed" ]] || fail "$label materialized native adapter state"
+  if [[ -e "$root/.zed" ]]; then
+    [[ -d "$root/.zed" && ! -L "$root/.zed" ]] \
+      || fail "$label created unsafe .zed state"
+    unexpected_state="$(
+      find "$root/.zed" -mindepth 1 \
+        ! -path "$root/.zed/operation.lock" -print -quit
+    )"
+    [[ -z "$unexpected_state" ]] \
+      || fail "$label materialized native adapter state: $unexpected_state"
+    if [[ -e "$root/.zed/operation.lock" ]]; then
+      [[ -f "$root/.zed/operation.lock" && ! -L "$root/.zed/operation.lock" ]] \
+        || fail "$label left an unsafe operation lock"
+    fi
+  fi
   if [[ -d "$root/.zpkg-staging" ]]; then
     [[ -z "$(find "$root/.zpkg-staging" -mindepth 1 -print -quit)" ]] \
       || fail "$label left transaction state"
diff --git a/tests/nix/interop.nix b/tests/nix/interop.nix
index 7dcc948d..98707a33 100644
--- a/tests/nix/interop.nix
+++ b/tests/nix/interop.nix
@@ -72,6 +72,7 @@ let
       test -f .vendor/.zed/zed-pkg/docker-node-lib/package.json
       test -f node_modules/@zed-pkg/docker-node-lib/package.json
       test ! -e .vendor/.zed/zed-pkg/docker-node-lib/generated/output.txt
+      test ! -e .zed/operation.lock
       runHook postCheck
     '';