diff --git a/src/lib/onboard.ts b/src/lib/onboard.ts
index e92f0900dd..395858abc0 100644
--- a/src/lib/onboard.ts
+++ b/src/lib/onboard.ts
@@ -29,6 +29,7 @@ const {
 const { stopStaleDashboardListenersForSandbox } = require("./onboard/stale-gateway-cleanup");
 const extraPlaceholderKeysModule: typeof import("./onboard/extra-placeholder-keys") = require("./onboard/extra-placeholder-keys");
 const buildContextStage: typeof import("./onboard/build-context-stage") = require("./onboard/build-context-stage");
+const sandboxCreateLaunch: typeof import("./onboard/sandbox-create-launch") = require("./onboard/sandbox-create-launch");
 const {
   ensureOllamaLoopbackSystemdOverride,
 }: typeof import("./onboard/ollama-systemd") = require("./onboard/ollama-systemd");
@@ -62,8 +63,6 @@ const {
   selectResourceProfileForSandbox,
 }: typeof import("./onboard/resource-profile-selection") = require("./onboard/resource-profile-selection");
 const {
-  isValidProxyHost,
-  isValidProxyPort,
   patchStagedDockerfile,
 }: typeof import("./onboard/dockerfile-patch") = require("./onboard/dockerfile-patch");
 const {
@@ -185,7 +184,6 @@ type RunnerOptions = {
   openshellBinary?: string;
 };
 
-const { buildSubprocessEnv } = require("./subprocess-env");
 const {
   DASHBOARD_PORT,
   GATEWAY_PORT,
@@ -3136,77 +3134,18 @@ async function createSandbox(
     sandboxInferenceBaseUrlOverride,
     hermesToolGateways,
   );
-  // Only pass non-sensitive env vars to the sandbox. Credentials flow through
-  // OpenShell providers — the gateway injects them as placeholders and the L7
-  // proxy rewrites Authorization headers with real secrets at egress.
-  // See: crates/openshell-sandbox/src/secrets.rs (placeholder rewriting),
-  //      crates/openshell-router/src/backend.rs (inference auth injection).
-  //
-  // Use the shared allowlist (subprocess-env.ts) instead of the old
-  // blocklist. The blocklist only blocked 12 specific credential names
-  // and passed EVERYTHING else — including GITHUB_TOKEN,
-  // AWS_SECRET_ACCESS_KEY, SSH_AUTH_SOCK, KUBECONFIG, NPM_TOKEN, and
-  // any CI/CD secrets that happened to be in the host environment.
-  // The allowlist inverts the default: only known-safe env vars are forwarded.
-  // For sandbox create, also strip KUBECONFIG and SSH_AUTH_SOCK: the generic
-  // allowlist needs them for host-side subprocesses, but sandbox code must not
-  // access host Kubernetes or SSH-agent credentials.
-  const envArgs = [formatEnvAssignment("CHAT_UI_URL", chatUiUrl)];
-  // Always pass the effective dashboard port into the sandbox so
-  // nemoclaw-start.sh starts the gateway on the correct port. When the
-  // user sets CHAT_UI_URL with a custom port (e.g. :18790), the port
-  // must reach the container — otherwise _DASHBOARD_PORT defaults to
-  // 18789 and the gateway listens on the wrong port. (#2267, #1925)
-  const effectiveDashboardPort = getDashboardForwardPort(chatUiUrl);
-  envArgs.push(formatEnvAssignment("NEMOCLAW_DASHBOARD_PORT", effectiveDashboardPort));
-  require("./onboard/openclaw-runtime-env").appendOpenClawRuntimeEnvArgs(envArgs, agent);
-  onboardHermesDashboard.appendHermesDashboardEnvArgs(
-    envArgs,
-    hermesDashboardState,
-    formatEnvAssignment,
-  );
-  require("./onboard/host-proxy-env").appendHostProxyEnvArgs(envArgs);
-  // Propagate NEMOCLAW_PROXY_HOST / NEMOCLAW_PROXY_PORT to the runtime
-  // sandbox container. patchStagedDockerfile() already substitutes them
-  // into the build-time Dockerfile ARG/ENV, but `openshell sandbox create
-  // -- env … nemoclaw-start` only forwards the explicitly listed env vars
-  // — image-baked ENV does not propagate into the running pod. Without
-  // this, nemoclaw-start.sh:898 falls back to the default 10.200.0.1:3128
-  // and `HTTPS_PROXY` inside the sandbox ignores the host override. The
-  // build-time substitution and runtime env stay in sync as a result.
-  // Fixes #2424. Uses the shared isValidProxyHost / isValidProxyPort
-  // helpers so build-time and runtime validation stay aligned.
-  const sandboxProxyHost = process.env.NEMOCLAW_PROXY_HOST;
-  if (sandboxProxyHost && isValidProxyHost(sandboxProxyHost)) {
-    envArgs.push(formatEnvAssignment("NEMOCLAW_PROXY_HOST", sandboxProxyHost));
-  }
-  const sandboxProxyPort = process.env.NEMOCLAW_PROXY_PORT;
-  if (sandboxProxyPort && isValidProxyPort(sandboxProxyPort)) {
-    envArgs.push(formatEnvAssignment("NEMOCLAW_PROXY_PORT", sandboxProxyPort));
-  }
-  require("./onboard/extra-placeholder-keys").appendExtraPlaceholderKeysEnvArg(
-    envArgs,
-    extraPlaceholderKeys,
-    formatEnvAssignment,
-  );
   const sandboxReadyTimeoutSecs = getSandboxReadyTimeoutSecs(effectiveSandboxGpuConfig);
-  const sandboxEnv = buildSubprocessEnv();
-  // Remove host-infrastructure credentials that the generic allowlist
-  // permits for host-side processes but that must not enter the sandbox.
-  delete sandboxEnv.KUBECONFIG;
-  delete sandboxEnv.SSH_AUTH_SOCK;
-  // Run without piping through awk — the pipe masked non-zero exit codes
-  // from openshell because bash returns the status of the last pipeline
-  // command (awk, always 0) unless pipefail is set. Removing the pipe
-  // lets the real exit code flow through to run().
-  const sandboxStartupCommand = ["env", ...envArgs, "nemoclaw-start"];
-  const createCommand = `${openshellShellCommand([
-    "sandbox",
-    "create",
-    ...createArgs,
-    "--",
-    ...sandboxStartupCommand,
-  ])} 2>&1`;
+  const { createCommand, effectiveDashboardPort, sandboxEnv, sandboxStartupCommand } =
+    sandboxCreateLaunch.prepareSandboxCreateLaunch({
+      agent,
+      chatUiUrl,
+      createArgs,
+      env: process.env,
+      extraPlaceholderKeys,
+      getDashboardForwardPort,
+      hermesDashboardState,
+      openshellShellCommand,
+    });
   const dockerGpuCreatePatch = dockerGpuSandboxCreate.createDockerGpuSandboxCreatePatch({
     enabled: useDockerGpuPatch,
     sandboxName,
diff --git a/src/lib/onboard/sandbox-create-launch.test.ts b/src/lib/onboard/sandbox-create-launch.test.ts
new file mode 100644
index 0000000000..841edc1730
--- /dev/null
+++ b/src/lib/onboard/sandbox-create-launch.test.ts
@@ -0,0 +1,178 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import { execFileSync } from "node:child_process";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+import { describe, expect, it, vi } from "vitest";
+
+import { createOpenshellCliHelpers } from "../../../dist/lib/onboard/openshell-cli";
+import { prepareSandboxCreateLaunch } from "../../../dist/lib/onboard/sandbox-create-launch";
+
+const disabledHermesDashboardState = { config: null, enabled: false };
+
+describe("prepareSandboxCreateLaunch", () => {
+  it("builds the sandbox create command and runtime env envelope", () => {
+    const openshellShellCommand = vi.fn((args: string[]) => `openshell ${args.join(" ")}`);
+    const result = prepareSandboxCreateLaunch({
+      agent: { name: "openclaw", configPaths: { dir: "/sandbox/.custom-openclaw" } } as any,
+      chatUiUrl: "http://127.0.0.1:19000/",
+      createArgs: ["--from", "/tmp/build/Dockerfile", "--name", "demo"],
+      env: {
+        HTTP_PROXY: " http://proxy.example:8080 ",
+        NEMOCLAW_MINIMAL_BOOTSTRAP: "1",
+        NEMOCLAW_PROXY_HOST: "host.docker.internal",
+        NEMOCLAW_PROXY_PORT: "3129",
+      },
+      extraPlaceholderKeys: ["TELEGRAM_BOT_TOKEN_AGENT_A"],
+      getDashboardForwardPort: () => "19000",
+      hermesDashboardState: disabledHermesDashboardState,
+      openshellShellCommand,
+      buildEnv: () =>
+        ({
+          HOME: "/home/user",
+          KUBECONFIG: "/home/user/.kube/config",
+          SSH_AUTH_SOCK: "/tmp/agent.sock",
+        }) as Record<string, string>,
+    });
+
+    expect(result.effectiveDashboardPort).toBe("19000");
+    expect(result.envArgs).toEqual([
+      "CHAT_UI_URL=http://127.0.0.1:19000/",
+      "NEMOCLAW_DASHBOARD_PORT=19000",
+      "OPENCLAW_HOME=/sandbox",
+      "OPENCLAW_STATE_DIR=/sandbox/.custom-openclaw",
+      "OPENCLAW_WORKSPACE_DIR=/sandbox/.custom-openclaw/workspace",
+      "NEMOCLAW_MINIMAL_BOOTSTRAP=1",
+      "HTTP_PROXY=http://proxy.example:8080",
+      "NO_PROXY=localhost,127.0.0.1,host.docker.internal,host.containers.internal,::1,0.0.0.0,inference.local",
+      "no_proxy=localhost,127.0.0.1,host.docker.internal,host.containers.internal,::1,0.0.0.0,inference.local",
+      "NEMOCLAW_PROXY_HOST=host.docker.internal",
+      "NEMOCLAW_PROXY_PORT=3129",
+      "NEMOCLAW_EXTRA_PLACEHOLDER_KEYS=TELEGRAM_BOT_TOKEN_AGENT_A",
+    ]);
+    expect(result.sandboxEnv).toEqual({ HOME: "/home/user" });
+    expect(result.sandboxStartupCommand).toEqual(["env", ...result.envArgs, "nemoclaw-start"]);
+    expect(openshellShellCommand).toHaveBeenCalledWith([
+      "sandbox",
+      "create",
+      "--from",
+      "/tmp/build/Dockerfile",
+      "--name",
+      "demo",
+      "--",
+      ...result.sandboxStartupCommand,
+    ]);
+    expect(result.createCommand).toBe(
+      `openshell sandbox create --from /tmp/build/Dockerfile --name demo -- ${result.sandboxStartupCommand.join(" ")} 2>&1`,
+    );
+  });
+
+  it("adds Hermes dashboard env and skips OpenClaw env for non-OpenClaw agents", () => {
+    const result = prepareSandboxCreateLaunch({
+      agent: { name: "hermes" } as any,
+      chatUiUrl: "http://127.0.0.1:18789/",
+      createArgs: [],
+      env: {},
+      extraPlaceholderKeys: [],
+      getDashboardForwardPort: () => "18789",
+      hermesDashboardState: {
+        config: { enabled: true, internalPort: 8643, port: 18790, tuiEnabled: true },
+        enabled: true,
+      },
+      openshellShellCommand: (args) => args.join(" "),
+      buildEnv: () => ({}),
+    });
+
+    expect(result.envArgs).toEqual([
+      "CHAT_UI_URL=http://127.0.0.1:18789/",
+      "NEMOCLAW_DASHBOARD_PORT=18789",
+      "NEMOCLAW_HERMES_DASHBOARD=1",
+      "NEMOCLAW_HERMES_DASHBOARD_PORT=18790",
+      "NEMOCLAW_HERMES_DASHBOARD_INTERNAL_PORT=8643",
+      "NEMOCLAW_HERMES_DASHBOARD_TUI=1",
+    ]);
+  });
+
+  it("ignores invalid runtime proxy overrides", () => {
+    const result = prepareSandboxCreateLaunch({
+      agent: null,
+      chatUiUrl: "http://127.0.0.1:18789/",
+      createArgs: [],
+      env: {
+        NEMOCLAW_PROXY_HOST: "bad:ipv6::host",
+        NEMOCLAW_PROXY_PORT: "70000",
+      },
+      extraPlaceholderKeys: [],
+      getDashboardForwardPort: () => "18789",
+      hermesDashboardState: disabledHermesDashboardState,
+      openshellShellCommand: (args) => args.join(" "),
+      buildEnv: () => ({}),
+    });
+
+    expect(result.envArgs).not.toContain("NEMOCLAW_PROXY_HOST=bad:ipv6::host");
+    expect(result.envArgs).not.toContain("NEMOCLAW_PROXY_PORT=70000");
+  });
+
+  it("preserves argv boundaries when the production renderer shells out", () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "nemoclaw-launch-shell-"));
+    try {
+      const fakeOpenshell = path.join(tmpDir, "fake openshell");
+      const capturedArgsPath = path.join(tmpDir, "argv.bin");
+      const injectedFromPath = path.join(tmpDir, "from-injected");
+      const injectedUrlPath = path.join(tmpDir, "url-injected");
+      const injectedProxyPath = path.join(tmpDir, "proxy-injected");
+      fs.writeFileSync(
+        fakeOpenshell,
+        '#!/usr/bin/env bash\nprintf \'%s\\0\' "$@" > "$CAPTURE_ARGS"\n',
+      );
+      fs.chmodSync(fakeOpenshell, 0o755);
+
+      const helpers = createOpenshellCliHelpers({
+        getCachedBinary: () => fakeOpenshell,
+        setCachedBinary: vi.fn(),
+        getGatewayPort: () => 31818,
+        getDockerDriverGatewayEndpoint: () => "http://127.0.0.1:31818",
+      });
+      const dangerousDockerfile = `${tmpDir}/Dockerfile; touch ${injectedFromPath}`;
+      const dangerousChatUiUrl = `http://127.0.0.1:19000/?q='; touch ${injectedUrlPath} #`;
+      const dangerousProxy = `http://proxy.example:8080/'; touch ${injectedProxyPath} #`;
+      const result = prepareSandboxCreateLaunch({
+        agent: null,
+        chatUiUrl: dangerousChatUiUrl,
+        createArgs: ["--from", dangerousDockerfile, "--name", "demo; echo pwned"],
+        env: { HTTP_PROXY: dangerousProxy },
+        extraPlaceholderKeys: ["TELEGRAM_BOT_TOKEN_AGENT_A"],
+        getDashboardForwardPort: () => "19000",
+        hermesDashboardState: disabledHermesDashboardState,
+        openshellShellCommand: helpers.openshellShellCommand,
+        buildEnv: () => ({}),
+      });
+
+      execFileSync("bash", ["-lc", result.createCommand], {
+        env: { ...process.env, CAPTURE_ARGS: capturedArgsPath },
+      });
+
+      const capturedArgs = fs.readFileSync(capturedArgsPath, "utf-8").split("\0").filter(Boolean);
+      expect(capturedArgs).toEqual([
+        "sandbox",
+        "create",
+        "--from",
+        dangerousDockerfile,
+        "--name",
+        "demo; echo pwned",
+        "--",
+        "env",
+        ...result.envArgs,
+        "nemoclaw-start",
+      ]);
+      expect(fs.existsSync(injectedFromPath)).toBe(false);
+      expect(fs.existsSync(injectedUrlPath)).toBe(false);
+      expect(fs.existsSync(injectedProxyPath)).toBe(false);
+    } finally {
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+  });
+});
diff --git a/src/lib/onboard/sandbox-create-launch.ts b/src/lib/onboard/sandbox-create-launch.ts
new file mode 100644
index 0000000000..9c224dd88c
--- /dev/null
+++ b/src/lib/onboard/sandbox-create-launch.ts
@@ -0,0 +1,99 @@
+// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+import type { AgentDefinition } from "../agent/defs";
+import { formatEnvAssignment } from "../core/url-utils";
+import { buildSubprocessEnv } from "../subprocess-env";
+import { isValidProxyHost, isValidProxyPort } from "./dockerfile-patch";
+import { appendExtraPlaceholderKeysEnvArg } from "./extra-placeholder-keys";
+import type { HermesDashboardOnboardState } from "./hermes-dashboard";
+import { appendHermesDashboardEnvArgs } from "./hermes-dashboard";
+import { appendHostProxyEnvArgs } from "./host-proxy-env";
+import { appendOpenClawRuntimeEnvArgs } from "./openclaw-runtime-env";
+
+type OpenshellShellCommand = (args: string[]) => string;
+
+export interface SandboxCreateLaunchInput {
+  agent: AgentDefinition | null | undefined;
+  chatUiUrl: string;
+  createArgs: readonly string[];
+  env?: NodeJS.ProcessEnv;
+  extraPlaceholderKeys: readonly string[];
+  getDashboardForwardPort(chatUiUrl: string): string;
+  hermesDashboardState: HermesDashboardOnboardState;
+  openshellShellCommand: OpenshellShellCommand;
+  buildEnv?(): Record<string, string>;
+}
+
+export interface SandboxCreateLaunch {
+  createCommand: string;
+  effectiveDashboardPort: string;
+  envArgs: string[];
+  sandboxEnv: Record<string, string>;
+  sandboxStartupCommand: string[];
+}
+
+export function prepareSandboxCreateLaunch(input: SandboxCreateLaunchInput): SandboxCreateLaunch {
+  const env = input.env ?? process.env;
+  const envArgs = [formatEnvAssignment("CHAT_UI_URL", input.chatUiUrl)];
+
+  // Always pass the effective dashboard port into the sandbox so
+  // nemoclaw-start.sh starts the gateway on the correct port. When the
+  // user sets CHAT_UI_URL with a custom port (e.g. :18790), the port
+  // must reach the container; otherwise _DASHBOARD_PORT defaults to
+  // 18789 and the gateway listens on the wrong port. (#2267, #1925)
+  const effectiveDashboardPort = input.getDashboardForwardPort(input.chatUiUrl);
+  envArgs.push(formatEnvAssignment("NEMOCLAW_DASHBOARD_PORT", effectiveDashboardPort));
+
+  appendOpenClawRuntimeEnvArgs(envArgs, input.agent ?? null);
+  appendHermesDashboardEnvArgs(envArgs, input.hermesDashboardState, formatEnvAssignment);
+  appendHostProxyEnvArgs(envArgs, env);
+
+  // Propagate NEMOCLAW_PROXY_HOST / NEMOCLAW_PROXY_PORT to the runtime
+  // sandbox container. patchStagedDockerfile() already substitutes them
+  // into the build-time Dockerfile ARG/ENV, but `openshell sandbox create
+  // -- env ... nemoclaw-start` only forwards the explicitly listed env vars;
+  // image-baked ENV does not propagate into the running pod. Without
+  // this, nemoclaw-start.sh falls back to the default 10.200.0.1:3128
+  // and `HTTPS_PROXY` inside the sandbox ignores the host override. The
+  // build-time substitution and runtime env stay in sync as a result.
+  // Fixes #2424. Uses the shared isValidProxyHost / isValidProxyPort
+  // helpers so build-time and runtime validation stay aligned.
+  const sandboxProxyHost = env.NEMOCLAW_PROXY_HOST;
+  if (sandboxProxyHost && isValidProxyHost(sandboxProxyHost)) {
+    envArgs.push(formatEnvAssignment("NEMOCLAW_PROXY_HOST", sandboxProxyHost));
+  }
+  const sandboxProxyPort = env.NEMOCLAW_PROXY_PORT;
+  if (sandboxProxyPort && isValidProxyPort(sandboxProxyPort)) {
+    envArgs.push(formatEnvAssignment("NEMOCLAW_PROXY_PORT", sandboxProxyPort));
+  }
+
+  appendExtraPlaceholderKeysEnvArg(envArgs, input.extraPlaceholderKeys, formatEnvAssignment);
+
+  const sandboxEnv = (input.buildEnv ?? buildSubprocessEnv)();
+  // Remove host-infrastructure credentials that the generic allowlist
+  // permits for host-side processes but that must not enter the sandbox.
+  delete sandboxEnv.KUBECONFIG;
+  delete sandboxEnv.SSH_AUTH_SOCK;
+
+  // Run without piping through awk; the pipe masked non-zero exit codes
+  // from openshell because bash returns the status of the last pipeline
+  // command (awk, always 0) unless pipefail is set. Removing the pipe
+  // lets the real exit code flow through to run().
+  const sandboxStartupCommand = ["env", ...envArgs, "nemoclaw-start"];
+  const createCommand = `${input.openshellShellCommand([
+    "sandbox",
+    "create",
+    ...input.createArgs,
+    "--",
+    ...sandboxStartupCommand,
+  ])} 2>&1`;
+
+  return {
+    createCommand,
+    effectiveDashboardPort,
+    envArgs,
+    sandboxEnv,
+    sandboxStartupCommand,
+  };
+}