diff --git a/tests/test_addon_metadata.py b/tests/test_addon_metadata.py
index 090fce7..9776b15 100644
--- a/tests/test_addon_metadata.py
+++ b/tests/test_addon_metadata.py
@@ -100,3 +100,27 @@ def test_dockerfile_patches_parent_cloakserve_instead_of_copying_a_binary() -> N
 def test_runtime_accepts_docker_port_unpublished_status() -> None:
     runtime_test = (ROOT / "tests/test_runtime.sh").read_text(encoding="utf-8")
     assert 'docker port "$container" 9222/tcp 2>/dev/null || true' in runtime_test
+
+
+def test_runtime_requires_process_baseline_after_cdp_close_and_zero_stopped_pid() -> None:
+    runtime_test = (ROOT / "tests/test_runtime.sh").read_text(encoding="utf-8")
+    assert 'docker top "$container" -eo pid,args' in runtime_test
+    for prefix in ("first", "second"):
+        container = f"${prefix}_container"
+        baseline = (
+            f'{prefix}_baseline="$(capture_process_baseline "{container}")"'
+        )
+        ready_index = runtime_test.index(
+            f'wait_ready "{container}" "${prefix}_port"'
+        )
+        baseline_index = runtime_test.index(baseline)
+        close_index = runtime_test.index(
+            f'probe_and_close_cdp "{container}"', baseline_index
+        )
+        return_index = runtime_test.index(
+            f'assert_processes_return_to_baseline "{container}" "${prefix}_baseline"',
+            close_index,
+        )
+        assert ready_index < baseline_index < close_index < return_index
+    assert "{{.State.Pid}}" in runtime_test
+    assert '[ "$state" = "exited 0 0" ]' in runtime_test
diff --git a/tests/test_runtime.sh b/tests/test_runtime.sh
index daa905c..19486f9 100755
--- a/tests/test_runtime.sh
+++ b/tests/test_runtime.sh
@@ -108,6 +108,76 @@ wait_ready() {
     fail "$container did not become ready within 90 seconds"
 }
 
+normalized_process_commands() {
+    local container="$1"
+    local top_file="${tmp_dir}/${container}-processes.txt"
+    docker top "$container" -eo pid,args > "$top_file"
+    python3 - "$top_file" <<'PY'
+import pathlib
+import sys
+
+commands = []
+for raw_line in pathlib.Path(sys.argv[1]).read_text(encoding="utf-8").splitlines()[1:]:
+    fields = raw_line.split(maxsplit=1)
+    command = " ".join(fields[1].split()) if len(fields) == 2 else ""
+    lowered = command.lower()
+    if "/usr/local/bin/addon-supervisor" in command:
+        commands.append("addon-supervisor")
+    elif "/usr/local/bin/cloakserve" in command:
+        commands.append("cloakserve")
+    elif "/usr/local/bin/stelloauth" in command:
+        commands.append("stelloauth")
+    elif (
+        ("/run/rosetta/rosetta" in lowered or "qemu-" in lowered)
+        and "chrome" not in lowered
+        and "chromium" not in lowered
+        and "headless_shell" not in lowered
+    ):
+        continue
+    elif command:
+        commands.append(f"unexpected:{command}")
+
+print("\n".join(sorted(commands)))
+PY
+}
+
+capture_process_baseline() {
+    local container="$1"
+    local expected current
+    local deadline=$((SECONDS + 10))
+    expected=$'addon-supervisor\ncloakserve\nstelloauth'
+    while (( SECONDS < deadline )); do
+        current="$(normalized_process_commands "$container")"
+        if [ "$current" = "$expected" ]; then
+            printf '%s\n' "$current"
+            return
+        fi
+        sleep 0.25
+    done
+    printf 'expected startup process baseline:\n%s\ncurrent process commands:\n%s\n' \
+        "$expected" "$current" >&2
+    docker top "$container" >&2
+    fail "$container did not reach the expected startup process baseline"
+}
+
+assert_processes_return_to_baseline() {
+    local container="$1"
+    local baseline="$2"
+    local current
+    local deadline=$((SECONDS + 10))
+    while (( SECONDS < deadline )); do
+        current="$(normalized_process_commands "$container")"
+        if [ "$current" = "$baseline" ]; then
+            return
+        fi
+        sleep 0.25
+    done
+    printf 'expected process baseline after CDP close:\n%s\ncurrent process commands:\n%s\n' \
+        "$baseline" "$current" >&2
+    docker top "$container" >&2
+    fail "$container retained browser or profile processes after CDP close"
+}
+
 assert_loopback_cdp_listener() {
     local container="$1"
     local artifact="$2"
@@ -243,8 +313,8 @@ import sys
 if float(sys.argv[1]) > 10.0:
     raise SystemExit(f"container stop exceeded 10 seconds: {sys.argv[1]}")
 PY
-    state="$(docker inspect --format '{{.State.Status}} {{.State.ExitCode}}' "$container")"
-    [ "$state" = "exited 0" ] || fail "$container state is $state, want exited 0"
+    state="$(docker inspect --format '{{.State.Status}} {{.State.ExitCode}} {{.State.Pid}}' "$container")"
+    [ "$state" = "exited 0 0" ] || fail "$container state is $state, want exited 0 with PID 0"
 }
 
 mkdir -p "$artifacts_dir"
@@ -262,9 +332,11 @@ fi
 start_container "$first_container"
 first_port="$(host_port "$first_container")"
 wait_ready "$first_container" "$first_port"
+first_baseline="$(capture_process_baseline "$first_container")"
 assert_no_9222_mapping "$first_container"
 assert_loopback_cdp_listener "$first_container" "${artifacts_dir}/runtime-proc-net-tcp.txt"
 probe_and_close_cdp "$first_container"
+assert_processes_return_to_baseline "$first_container" "$first_baseline"
 post_invalid_worker "$first_port" "${artifacts_dir}/runtime-invalid-worker-response.json"
 scan_logs "$first_container"
 stop_and_assert "$first_container" "${artifacts_dir}/runtime-first-stop.txt"
@@ -273,9 +345,11 @@ scan_logs "$first_container"
 start_container "$second_container"
 second_port="$(host_port "$second_container")"
 wait_ready "$second_container" "$second_port"
+second_baseline="$(capture_process_baseline "$second_container")"
 assert_no_9222_mapping "$second_container"
 assert_loopback_cdp_listener "$second_container" "${artifacts_dir}/runtime-restart-proc-net-tcp.txt"
 probe_and_close_cdp "$second_container"
+assert_processes_return_to_baseline "$second_container" "$second_baseline"
 
 sleep 5
 docker stats --no-stream "$second_container" > "${artifacts_dir}/runtime-docker-stats.txt"