diff --git a/extensions/codex/harness.ts b/extensions/codex/harness.ts
index 5879e8d1089..aa91b3c6821 100644
--- a/extensions/codex/harness.ts
+++ b/extensions/codex/harness.ts
@@ -8,6 +8,7 @@ import type {
 } from "./src/app-server/models.js";
 import { runCodexAppServerAttempt } from "./src/app-server/run-attempt.js";
 import { clearCodexAppServerBinding } from "./src/app-server/session-binding.js";
+import { clearSharedCodexAppServerClient } from "./src/app-server/shared-client.js";
 
 const DEFAULT_CODEX_HARNESS_PROVIDER_IDS = new Set(["codex", "openai-codex"]);
 
@@ -47,5 +48,8 @@ export function createCodexAppServerAgentHarness(options?: {
         await clearCodexAppServerBinding(params.sessionFile);
       }
     },
+    dispose: () => {
+      clearSharedCodexAppServerClient();
+    },
   };
 }
diff --git a/extensions/codex/index.test.ts b/extensions/codex/index.test.ts
index 07940a30f7a..37c405a91c1 100644
--- a/extensions/codex/index.test.ts
+++ b/extensions/codex/index.test.ts
@@ -35,6 +35,7 @@ describe("codex plugin", () => {
     expect(registerAgentHarness.mock.calls[0]?.[0]).toMatchObject({
       id: "codex",
       label: "Codex agent harness",
+      dispose: expect.any(Function),
     });
     expect(registerCommand.mock.calls[0]?.[0]).toMatchObject({
       name: "codex",
diff --git a/extensions/codex/provider.test.ts b/extensions/codex/provider.test.ts
index f4cd789a7bf..3d1c26b0266 100644
--- a/extensions/codex/provider.test.ts
+++ b/extensions/codex/provider.test.ts
@@ -1,5 +1,12 @@
-import { describe, expect, it, vi } from "vitest";
+import { afterEach, describe, expect, it, vi } from "vitest";
 import { buildCodexProvider, buildCodexProviderCatalog } from "./provider.js";
+import { CodexAppServerClient } from "./src/app-server/client.js";
+import { resetSharedCodexAppServerClientForTests } from "./src/app-server/shared-client.js";
+
+afterEach(() => {
+  resetSharedCodexAppServerClientForTests();
+  vi.restoreAllMocks();
+});
 
 describe("codex provider", () => {
   it("maps Codex app-server models to a Codex provider catalog", async () => {
@@ -64,17 +71,49 @@ describe("codex provider", () => {
     ]);
   });
 
+  it("keeps a static fallback catalog when live discovery is explicitly disabled by env", async () => {
+    const listModels = vi.fn();
+
+    const result = await buildCodexProviderCatalog({
+      env: { OPENCLAW_CODEX_DISCOVERY_LIVE: "0" },
+      listModels,
+    });
+
+    expect(listModels).not.toHaveBeenCalled();
+    expect(result.provider.models.map((model) => model.id)).toEqual([
+      "gpt-5.4",
+      "gpt-5.4-mini",
+      "gpt-5.2",
+    ]);
+  });
+
+  it("closes the transient app-server client after live discovery", async () => {
+    const client = {
+      initialize: vi.fn(async () => undefined),
+      request: vi.fn(async () => ({ data: [] })),
+      addCloseHandler: vi.fn(() => () => undefined),
+      close: vi.fn(),
+    } as unknown as CodexAppServerClient;
+    vi.spyOn(CodexAppServerClient, "start").mockReturnValue(client);
+
+    await buildCodexProviderCatalog({
+      env: { OPENCLAW_CODEX_DISCOVERY_LIVE: "1" },
+    });
+
+    expect(client.close).toHaveBeenCalledTimes(1);
+  });
+
   it("resolves arbitrary Codex app-server model ids through the codex provider", () => {
     const provider = buildCodexProvider();
 
     const model = provider.resolveDynamicModel?.({
       provider: "codex",
-      modelId: " arcanine ",
+      modelId: " custom-model ",
       modelRegistry: { find: () => null },
     } as never);
 
     expect(model).toMatchObject({
-      id: "arcanine",
+      id: "custom-model",
       provider: "codex",
       api: "openai-codex-responses",
       baseUrl: "https://chatgpt.com/backend-api",
diff --git a/extensions/codex/provider.ts b/extensions/codex/provider.ts
index 4501efc2d55..c737a24ad58 100644
--- a/extensions/codex/provider.ts
+++ b/extensions/codex/provider.ts
@@ -15,6 +15,7 @@ import {
   readCodexPluginConfig,
   resolveCodexAppServerRuntimeOptions,
 } from "./src/app-server/config.js";
+import { clearSharedCodexAppServerClient } from "./src/app-server/shared-client.js";
 
 const PROVIDER_ID = "codex";
 const CODEX_BASE_URL = "https://chatgpt.com/backend-api";
@@ -99,14 +100,18 @@ export async function buildCodexProviderCatalog(
   const config = readCodexPluginConfig(options.pluginConfig);
   const appServer = resolveCodexAppServerRuntimeOptions({ pluginConfig: options.pluginConfig });
   const timeoutMs = normalizeTimeoutMs(config.discovery?.timeoutMs);
-  const discovered =
-    config.discovery?.enabled === false || shouldSkipLiveDiscovery(options.env)
-      ? []
-      : await listModelsBestEffort({
-          listModels: options.listModels ?? listCodexAppServerModels,
-          timeoutMs,
-          startOptions: appServer.start,
-        });
+  let discovered: CodexAppServerModel[] = [];
+  if (config.discovery?.enabled !== false && !shouldSkipLiveDiscovery(options.env)) {
+    try {
+      discovered = await listModelsBestEffort({
+        listModels: options.listModels ?? listCodexAppServerModels,
+        timeoutMs,
+        startOptions: appServer.start,
+      });
+    } finally {
+      clearSharedCodexAppServerClient();
+    }
+  }
   const models = (discovered.length > 0 ? discovered : FALLBACK_CODEX_MODELS).map(
     codexModelToDefinition,
   );
@@ -189,7 +194,11 @@ function normalizeTimeoutMs(value: unknown): number {
 }
 
 function shouldSkipLiveDiscovery(env: NodeJS.ProcessEnv = process.env): boolean {
-  return Boolean(env.VITEST) && env[LIVE_DISCOVERY_ENV] !== "1";
+  const override = env[LIVE_DISCOVERY_ENV]?.trim().toLowerCase();
+  if (override === "0" || override === "false") {
+    return true;
+  }
+  return Boolean(env.VITEST) && override !== "1";
 }
 
 function shouldDefaultToReasoningModel(modelId: string): boolean {
diff --git a/extensions/codex/src/app-server/client.test.ts b/extensions/codex/src/app-server/client.test.ts
index eb7718d7c27..b8dc9b8648a 100644
--- a/extensions/codex/src/app-server/client.test.ts
+++ b/extensions/codex/src/app-server/client.test.ts
@@ -2,6 +2,7 @@ import { EventEmitter } from "node:events";
 import { PassThrough, Writable } from "node:stream";
 import { afterEach, describe, expect, it, vi } from "vitest";
 import {
+  __testing,
   CodexAppServerClient,
   CodexAppServerRpcError,
   MIN_CODEX_APP_SERVER_VERSION,
@@ -47,6 +48,7 @@ describe("CodexAppServerClient", () => {
   afterEach(() => {
     resetSharedCodexAppServerClientForTests();
     vi.restoreAllMocks();
+    vi.useRealTimers();
     for (const client of clients) {
       client.close();
     }
@@ -141,6 +143,30 @@ describe("CodexAppServerClient", () => {
     expect(harness.writes).toHaveLength(1);
   });
 
+  it("force-stops app-server transports that ignore the graceful signal", async () => {
+    vi.useFakeTimers();
+    const process = Object.assign(new EventEmitter(), {
+      stdin: {
+        write: vi.fn(),
+        end: vi.fn(),
+        destroy: vi.fn(),
+        unref: vi.fn(),
+      },
+      stdout: Object.assign(new PassThrough(), { unref: vi.fn() }),
+      stderr: Object.assign(new PassThrough(), { unref: vi.fn() }),
+      exitCode: null,
+      signalCode: null,
+      kill: vi.fn(),
+      unref: vi.fn(),
+    });
+
+    __testing.closeCodexAppServerTransport(process, { forceKillDelayMs: 25 });
+
+    expect(process.kill).toHaveBeenCalledWith("SIGTERM");
+    await vi.advanceTimersByTimeAsync(25);
+    expect(process.kill).toHaveBeenCalledWith("SIGKILL");
+    expect(process.unref).toHaveBeenCalledTimes(1);
+  });
   it("reads the Codex version from the app-server user agent", () => {
     expect(readCodexVersionFromUserAgent("openclaw/0.118.0 (macOS; test)")).toBe("0.118.0");
     expect(readCodexVersionFromUserAgent("codex_cli_rs/0.118.1-dev (linux; test)")).toBe(
diff --git a/extensions/codex/src/app-server/client.ts b/extensions/codex/src/app-server/client.ts
index fc3c1b94a6b..3bb1e1de0a0 100644
--- a/extensions/codex/src/app-server/client.ts
+++ b/extensions/codex/src/app-server/client.ts
@@ -12,7 +12,7 @@ import {
 } from "./protocol.js";
 import { createStdioTransport } from "./transport-stdio.js";
 import { createWebSocketTransport } from "./transport-websocket.js";
-import type { CodexAppServerTransport } from "./transport.js";
+import { closeCodexAppServerTransport, type CodexAppServerTransport } from "./transport.js";
 
 export const MIN_CODEX_APP_SERVER_VERSION = "0.118.0";
 
@@ -149,11 +149,13 @@ export class CodexAppServerClient {
   }
 
   close(): void {
+    if (this.closed) {
+      return;
+    }
     this.closed = true;
     this.lines.close();
-    if (!this.child.killed) {
-      this.child.kill?.();
-    }
+    this.rejectPendingRequests(new Error("codex app-server client is closed"));
+    closeCodexAppServerTransport(this.child);
   }
 
   private writeMessage(message: RpcRequest | RpcResponse): void {
@@ -245,6 +247,10 @@ export class CodexAppServerClient {
       return;
     }
     this.closed = true;
+    this.rejectPendingRequests(error);
+  }
+
+  private rejectPendingRequests(error: Error): void {
     for (const pending of this.pending.values()) {
       pending.reject(error);
     }
@@ -354,3 +360,7 @@ function formatExitValue(value: unknown): string {
   }
   return "unknown";
 }
+
+export const __testing = {
+  closeCodexAppServerTransport,
+} as const;
diff --git a/extensions/codex/src/app-server/shared-client.ts b/extensions/codex/src/app-server/shared-client.ts
index 90f1978de3c..12ca87f12cf 100644
--- a/extensions/codex/src/app-server/shared-client.ts
+++ b/extensions/codex/src/app-server/shared-client.ts
@@ -5,22 +5,35 @@ import {
   type CodexAppServerStartOptions,
 } from "./config.js";
 
-let sharedClient: CodexAppServerClient | undefined;
-let sharedClientPromise: Promise<CodexAppServerClient> | undefined;
-let sharedClientKey: string | undefined;
+type SharedCodexAppServerClientState = {
+  client?: CodexAppServerClient;
+  promise?: Promise<CodexAppServerClient>;
+  key?: string;
+};
+
+const SHARED_CODEX_APP_SERVER_CLIENT_STATE = Symbol.for("openclaw.codexAppServerClientState");
+
+function getSharedCodexAppServerClientState(): SharedCodexAppServerClientState {
+  const globalState = globalThis as typeof globalThis & {
+    [SHARED_CODEX_APP_SERVER_CLIENT_STATE]?: SharedCodexAppServerClientState;
+  };
+  globalState[SHARED_CODEX_APP_SERVER_CLIENT_STATE] ??= {};
+  return globalState[SHARED_CODEX_APP_SERVER_CLIENT_STATE];
+}
 
 export async function getSharedCodexAppServerClient(options?: {
   startOptions?: CodexAppServerStartOptions;
 }): Promise<CodexAppServerClient> {
+  const state = getSharedCodexAppServerClientState();
   const startOptions = options?.startOptions ?? resolveCodexAppServerRuntimeOptions().start;
   const key = codexAppServerStartOptionsKey(startOptions);
-  if (sharedClientKey && sharedClientKey !== key) {
+  if (state.key && state.key !== key) {
     clearSharedCodexAppServerClient();
   }
-  sharedClientKey = key;
-  sharedClientPromise ??= (async () => {
+  state.key = key;
+  state.promise ??= (async () => {
     const client = CodexAppServerClient.start(startOptions);
-    sharedClient = client;
+    state.client = client;
     client.addCloseHandler(clearSharedClientIfCurrent);
     try {
       await client.initialize();
@@ -33,34 +46,37 @@ export async function getSharedCodexAppServerClient(options?: {
     }
   })();
   try {
-    return await sharedClientPromise;
+    return await state.promise;
   } catch (error) {
-    sharedClient = undefined;
-    sharedClientPromise = undefined;
-    sharedClientKey = undefined;
+    state.client = undefined;
+    state.promise = undefined;
+    state.key = undefined;
     throw error;
   }
 }
 
 export function resetSharedCodexAppServerClientForTests(): void {
-  sharedClient = undefined;
-  sharedClientPromise = undefined;
-  sharedClientKey = undefined;
+  const state = getSharedCodexAppServerClientState();
+  state.client = undefined;
+  state.promise = undefined;
+  state.key = undefined;
 }
 
 export function clearSharedCodexAppServerClient(): void {
-  const client = sharedClient;
-  sharedClient = undefined;
-  sharedClientPromise = undefined;
-  sharedClientKey = undefined;
+  const state = getSharedCodexAppServerClientState();
+  const client = state.client;
+  state.client = undefined;
+  state.promise = undefined;
+  state.key = undefined;
   client?.close();
 }
 
 function clearSharedClientIfCurrent(client: CodexAppServerClient): void {
-  if (sharedClient !== client) {
+  const state = getSharedCodexAppServerClientState();
+  if (state.client !== client) {
     return;
   }
-  sharedClient = undefined;
-  sharedClientPromise = undefined;
-  sharedClientKey = undefined;
+  state.client = undefined;
+  state.promise = undefined;
+  state.key = undefined;
 }
diff --git a/extensions/codex/src/app-server/transport-stdio.ts b/extensions/codex/src/app-server/transport-stdio.ts
index c9c5feb72b0..17bc84da453 100644
--- a/extensions/codex/src/app-server/transport-stdio.ts
+++ b/extensions/codex/src/app-server/transport-stdio.ts
@@ -5,6 +5,7 @@ import type { CodexAppServerTransport } from "./transport.js";
 export function createStdioTransport(options: CodexAppServerStartOptions): CodexAppServerTransport {
   return spawn(options.command, options.args, {
     env: process.env,
+    detached: process.platform !== "win32",
     stdio: ["pipe", "pipe", "pipe"],
   });
 }
diff --git a/extensions/codex/src/app-server/transport.ts b/extensions/codex/src/app-server/transport.ts
index d7d14187bf2..423d7f0c474 100644
--- a/extensions/codex/src/app-server/transport.ts
+++ b/extensions/codex/src/app-server/transport.ts
@@ -1,8 +1,72 @@
 export type CodexAppServerTransport = {
-  stdin: { write: (data: string) => unknown };
-  stdout: NodeJS.ReadableStream;
-  stderr: NodeJS.ReadableStream;
+  stdin: {
+    write: (data: string) => unknown;
+    end?: () => unknown;
+    destroy?: () => unknown;
+    unref?: () => unknown;
+  };
+  stdout: NodeJS.ReadableStream & {
+    destroy?: () => unknown;
+    unref?: () => unknown;
+  };
+  stderr: NodeJS.ReadableStream & {
+    destroy?: () => unknown;
+    unref?: () => unknown;
+  };
+  pid?: number;
+  exitCode?: number | null;
+  signalCode?: string | null;
   killed?: boolean;
-  kill?: () => unknown;
+  kill?: (signal?: NodeJS.Signals) => unknown;
+  unref?: () => unknown;
   once: (event: string, listener: (...args: unknown[]) => void) => unknown;
 };
+
+export function closeCodexAppServerTransport(
+  child: CodexAppServerTransport,
+  options: { forceKillDelayMs?: number } = {},
+): void {
+  child.stdout.destroy?.();
+  child.stderr.destroy?.();
+  child.stdin.end?.();
+  child.stdin.destroy?.();
+  signalCodexAppServerTransport(child, "SIGTERM");
+  const forceKillDelayMs = options.forceKillDelayMs ?? 1_000;
+  const forceKill = setTimeout(
+    () => {
+      if (hasCodexAppServerTransportExited(child)) {
+        return;
+      }
+      signalCodexAppServerTransport(child, "SIGKILL");
+    },
+    Math.max(1, forceKillDelayMs),
+  );
+  forceKill.unref?.();
+  child.once("exit", () => clearTimeout(forceKill));
+  child.unref?.();
+  child.stdout.unref?.();
+  child.stderr.unref?.();
+  child.stdin.unref?.();
+}
+
+function hasCodexAppServerTransportExited(child: CodexAppServerTransport): boolean {
+  return child.exitCode !== null && child.exitCode !== undefined
+    ? true
+    : child.signalCode !== null && child.signalCode !== undefined;
+}
+
+function signalCodexAppServerTransport(
+  child: CodexAppServerTransport,
+  signal: NodeJS.Signals,
+): void {
+  if (child.pid && process.platform !== "win32") {
+    try {
+      process.kill(-child.pid, signal);
+      return;
+    } catch {
+      // Fall back to the child handle. The process may already be gone or not
+      // be a process-group leader on older call sites.
+    }
+  }
+  child.kill?.(signal);
+}
diff --git a/src/agents/harness/index.ts b/src/agents/harness/index.ts
index 45369279449..6a1d5e9e3af 100644
--- a/src/agents/harness/index.ts
+++ b/src/agents/harness/index.ts
@@ -1,5 +1,6 @@
 export {
   clearAgentHarnesses,
+  disposeRegisteredAgentHarnesses,
   getAgentHarness,
   getRegisteredAgentHarness,
   listAgentHarnessIds,
diff --git a/src/agents/harness/registry.test.ts b/src/agents/harness/registry.test.ts
index db2d2c2d014..07b14f09bff 100644
--- a/src/agents/harness/registry.test.ts
+++ b/src/agents/harness/registry.test.ts
@@ -1,6 +1,7 @@
-import { afterEach, describe, expect, it } from "vitest";
+import { afterEach, describe, expect, it, vi } from "vitest";
 import {
   clearAgentHarnesses,
+  disposeRegisteredAgentHarnesses,
   getAgentHarness,
   getRegisteredAgentHarness,
   listAgentHarnessIds,
@@ -96,6 +97,18 @@ describe("agent harness registry", () => {
     ]);
   });
 
+  it("disposes registered harness runtime state", async () => {
+    const dispose = vi.fn(async () => undefined);
+    registerAgentHarness({
+      ...makeHarness("custom"),
+      dispose,
+    });
+
+    await disposeRegisteredAgentHarnesses();
+
+    expect(dispose).toHaveBeenCalledTimes(1);
+  });
+
   it("keeps model-specific harnesses behind plugin registration in auto mode", () => {
     process.env.OPENCLAW_AGENT_RUNTIME = "auto";
 
diff --git a/src/agents/harness/registry.ts b/src/agents/harness/registry.ts
index c5541cce7c0..695f6096a37 100644
--- a/src/agents/harness/registry.ts
+++ b/src/agents/harness/registry.ts
@@ -80,3 +80,21 @@ export async function resetRegisteredAgentHarnessSessions(
     }),
   );
 }
+
+export async function disposeRegisteredAgentHarnesses(): Promise<void> {
+  await Promise.all(
+    listRegisteredAgentHarnesses().map(async (entry) => {
+      if (!entry.harness.dispose) {
+        return;
+      }
+      try {
+        await entry.harness.dispose();
+      } catch (error) {
+        log.warn(`${entry.harness.label} dispose hook failed`, {
+          harnessId: entry.harness.id,
+          error,
+        });
+      }
+    }),
+  );
+}
diff --git a/src/gateway/server-close.test.ts b/src/gateway/server-close.test.ts
index b325032a479..823fc1bf047 100644
--- a/src/gateway/server-close.test.ts
+++ b/src/gateway/server-close.test.ts
@@ -2,6 +2,7 @@ import { beforeEach, describe, expect, it, vi } from "vitest";
 
 const mocks = {
   logWarn: vi.fn(),
+  disposeAgentHarnesses: vi.fn(async () => undefined),
 };
 const WEBSOCKET_CLOSE_GRACE_MS = 1_000;
 const WEBSOCKET_CLOSE_FORCE_CONTINUE_MS = 250;
@@ -14,6 +15,10 @@ vi.mock("../hooks/gmail-watcher.js", () => ({
   stopGmailWatcher: vi.fn(async () => undefined),
 }));
 
+vi.mock("../agents/harness/registry.js", () => ({
+  disposeRegisteredAgentHarnesses: mocks.disposeAgentHarnesses,
+}));
+
 vi.mock("../logging/subsystem.js", () => ({
   createSubsystemLogger: vi.fn(() => ({
     warn: mocks.logWarn,
@@ -26,6 +31,7 @@ describe("createGatewayCloseHandler", () => {
   beforeEach(() => {
     vi.useRealTimers();
     mocks.logWarn.mockClear();
+    mocks.disposeAgentHarnesses.mockClear();
   });
 
   it("unsubscribes lifecycle listeners during shutdown", async () => {
@@ -66,6 +72,7 @@ describe("createGatewayCloseHandler", () => {
 
     expect(lifecycleUnsub).toHaveBeenCalledTimes(1);
     expect(stopTaskRegistryMaintenance).toHaveBeenCalledTimes(1);
+    expect(mocks.disposeAgentHarnesses).toHaveBeenCalledTimes(1);
   });
 
   it("terminates lingering websocket clients when websocket close exceeds the grace window", async () => {
diff --git a/src/gateway/server-close.ts b/src/gateway/server-close.ts
index 32e7c8b4c26..6457bbe567d 100644
--- a/src/gateway/server-close.ts
+++ b/src/gateway/server-close.ts
@@ -1,5 +1,6 @@
 import type { Server as HttpServer } from "node:http";
 import type { WebSocketServer } from "ws";
+import { disposeRegisteredAgentHarnesses } from "../agents/harness/registry.js";
 import type { CanvasHostHandler, CanvasHostServer } from "../canvas-host/server.js";
 import { type ChannelId, listChannelPlugins } from "../channels/plugins/index.js";
 import { stopGmailWatcher } from "../hooks/gmail-watcher.js";
@@ -98,6 +99,7 @@ export function createGatewayCloseHandler(params: {
       for (const plugin of listChannelPlugins()) {
         await params.stopChannel(plugin.id);
       }
+      await disposeRegisteredAgentHarnesses();
       if (params.pluginServices) {
         await params.pluginServices.stop().catch(() => {});
       }
diff --git a/src/plugin-sdk/agent-harness.ts b/src/plugin-sdk/agent-harness.ts
index 491879149df..6503f86643e 100644
--- a/src/plugin-sdk/agent-harness.ts
+++ b/src/plugin-sdk/agent-harness.ts
@@ -47,6 +47,7 @@ export {
   queueEmbeddedPiMessage as queueAgentHarnessMessage,
   setActiveEmbeddedRun,
 } from "../agents/pi-embedded-runner/runs.js";
+export { disposeRegisteredAgentHarnesses } from "../agents/harness/registry.js";
 export { normalizeProviderToolSchemas } from "../agents/pi-embedded-runner/tool-schema-runtime.js";
 export { createOpenClawCodingTools } from "../agents/pi-tools.js";
 export { resolveSandboxContext } from "../agents/sandbox.js";