diff --git a/src/agents/sandbox-create-args.test.ts b/src/agents/sandbox-create-args.test.ts
index 0d9621ad9e1..60b6241f58a 100644
--- a/src/agents/sandbox-create-args.test.ts
+++ b/src/agents/sandbox-create-args.test.ts
@@ -137,6 +137,33 @@ describe("buildSandboxCreateArgs", () => {
     );
   });
 
+  it("preserves the OpenClaw exec marker when strict env sanitization is enabled", () => {
+    const cfg = createSandboxConfig({
+      env: {
+        NODE_ENV: "test",
+      },
+    });
+
+    const args = buildSandboxCreateArgs({
+      name: "openclaw-sbx-marker",
+      cfg,
+      scopeKey: "main",
+      createdAtMs: 1700000000000,
+      envSanitizationOptions: {
+        strictMode: true,
+      },
+    });
+
+    expect(args).toEqual(
+      expect.arrayContaining([
+        "--env",
+        "NODE_ENV=test",
+        "--env",
+        `OPENCLAW_CLI=${OPENCLAW_CLI_ENV_VALUE}`,
+      ]),
+    );
+  });
+
   it("emits -v flags for safe custom binds", () => {
     const cfg: SandboxDockerConfig = {
       image: "openclaw-sandbox:bookworm-slim",
diff --git a/src/agents/sandbox/docker.ts b/src/agents/sandbox/docker.ts
index 68c95e343ea..aefceb08495 100644
--- a/src/agents/sandbox/docker.ts
+++ b/src/agents/sandbox/docker.ts
@@ -5,6 +5,7 @@ import {
   resolveWindowsSpawnProgram,
 } from "../../plugin-sdk/windows-spawn.js";
 import { sanitizeEnvVars } from "./sanitize-env-vars.js";
+import type { EnvSanitizationOptions } from "./sanitize-env-vars.js";
 
 type ExecDockerRawOptions = {
   allowFailure?: boolean;
@@ -52,7 +53,7 @@ export function resolveDockerSpawnInvocation(
     env: runtime.env,
     execPath: runtime.execPath,
     packageName: "docker",
-    allowShellFallback: true,
+    allowShellFallback: false,
   });
   const resolved = materializeWindowsSpawnProgram(program, args);
   return {
@@ -325,6 +326,7 @@ export function buildSandboxCreateArgs(params: {
   allowSourcesOutsideAllowedRoots?: boolean;
   allowReservedContainerTargets?: boolean;
   allowContainerNamespaceJoin?: boolean;
+  envSanitizationOptions?: EnvSanitizationOptions;
 }) {
   // Runtime security validation: blocks dangerous bind mounts, network modes, and profiles.
   validateSandboxSecurity({
@@ -366,14 +368,14 @@ export function buildSandboxCreateArgs(params: {
   if (params.cfg.user) {
     args.push("--user", params.cfg.user);
   }
-  const envSanitization = sanitizeEnvVars(markOpenClawExecEnv(params.cfg.env ?? {}));
+  const envSanitization = sanitizeEnvVars(params.cfg.env ?? {}, params.envSanitizationOptions);
   if (envSanitization.blocked.length > 0) {
     log.warn(`Blocked sensitive environment variables: ${envSanitization.blocked.join(", ")}`);
   }
   if (envSanitization.warnings.length > 0) {
     log.warn(`Suspicious environment variables: ${envSanitization.warnings.join(", ")}`);
   }
-  for (const [key, value] of Object.entries(envSanitization.allowed)) {
+  for (const [key, value] of Object.entries(markOpenClawExecEnv(envSanitization.allowed))) {
     args.push("--env", `${key}=${value}`);
   }
   for (const cap of params.cfg.capDrop) {
diff --git a/src/agents/sandbox/docker.windows.test.ts b/src/agents/sandbox/docker.windows.test.ts
index 3dd294e8360..7abebad98ab 100644
--- a/src/agents/sandbox/docker.windows.test.ts
+++ b/src/agents/sandbox/docker.windows.test.ts
@@ -47,22 +47,20 @@ describe("resolveDockerSpawnInvocation", () => {
     });
   });
 
-  it("falls back to shell mode when only unresolved docker.cmd wrapper exists", async () => {
+  it("rejects unresolved docker.cmd wrappers instead of shelling out", async () => {
     const dir = await createTempDir();
     const cmdPath = path.join(dir, "docker.cmd");
     await mkdir(path.dirname(cmdPath), { recursive: true });
     await writeFile(cmdPath, "@ECHO off\r\necho docker\r\n", "utf8");
 
-    const resolved = resolveDockerSpawnInvocation(["ps"], {
-      platform: "win32",
-      env: { PATH: dir, PATHEXT: ".CMD;.EXE;.BAT" },
-      execPath: "C:\\node\\node.exe",
-    });
-    expect(path.normalize(resolved.command).toLowerCase()).toBe(
-      path.normalize(cmdPath).toLowerCase(),
+    expect(() =>
+      resolveDockerSpawnInvocation(["ps"], {
+        platform: "win32",
+        env: { PATH: dir, PATHEXT: ".CMD;.EXE;.BAT" },
+        execPath: "C:\\node\\node.exe",
+      }),
+    ).toThrow(
+      /wrapper resolved, but no executable\/Node entrypoint could be resolved without shell execution\./i,
     );
-    expect(resolved.args).toEqual(["ps"]);
-    expect(resolved.shell).toBe(true);
-    expect(resolved.windowsHide).toBeUndefined();
   });
 });