diff --git a/internal/cloud/code-agent-session-registry.test.mjs b/internal/cloud/code-agent-session-registry.test.mjs
index 50b620ca..7682b01c 100644
--- a/internal/cloud/code-agent-session-registry.test.mjs
+++ b/internal/cloud/code-agent-session-registry.test.mjs
@@ -804,6 +804,66 @@ test("Code Agent PC gateway prompt reaches Codex stdio instead of internal hardw
   }
 });
 
+test("Codex stdio manager rebuilds app-server client when provider profile config changes", async () => {
+  const calls = [];
+  const createdModels = [];
+  const closedModels = [];
+  const fakeCodex = await createFakeCodexCommand();
+  const codexHome = await prepareFakeCodexHome();
+  const baseEnv = {
+    PATH: process.env.PATH,
+    OPENAI_API_KEY: "test-openai-key-material",
+    CODEX_HOME: codexHome,
+    HWLAB_CODE_AGENT_PROVIDER: "codex-stdio",
+    HWLAB_CODE_AGENT_CODEX_COMMAND: fakeCodex.command,
+    HWLAB_CODE_AGENT_CODEX_STDIO_ENABLED: "1",
+    HWLAB_CODE_AGENT_CODEX_STDIO_SUPERVISOR: "repo-owned",
+    HWLAB_CODE_AGENT_CODEX_SANDBOX: "danger-full-access",
+    HWLAB_CODE_AGENT_WORKSPACE: process.cwd()
+  };
+  const manager = createCodexStdioSessionManager({
+    idFactory: () => `ses_profile_${createdModels.length + 1}`,
+    createRpcClient: async ({ env }) => {
+      const model = env.HWLAB_CODE_AGENT_MODEL;
+      createdModels.push(model);
+      const client = createFakeAppServerClient({ calls, responses: [`reply from ${model}`] });
+      client.close = () => closedModels.push(model);
+      return client;
+    }
+  });
+
+  try {
+    await manager.chat({
+      conversationId: "cnv_profile_deepseek",
+      traceId: "trc_profile_deepseek",
+      message: "first",
+      env: {
+        ...baseEnv,
+        HWLAB_CODE_AGENT_MODEL: "deepseek-chat",
+        HWLAB_CODE_AGENT_OPENAI_BASE_URL: "http://hwlab-deepseek-proxy.hwlab-dev.svc.cluster.local:4000/v1/responses"
+      }
+    });
+    await manager.chat({
+      conversationId: "cnv_profile_codex",
+      traceId: "trc_profile_codex",
+      message: "second",
+      env: {
+        ...baseEnv,
+        HWLAB_CODE_AGENT_MODEL: "gpt-5.5",
+        HWLAB_CODE_AGENT_OPENAI_BASE_URL: "http://172.26.26.227:17680/v1/responses"
+      }
+    });
+
+    assert.deepEqual(createdModels, ["deepseek-chat", "gpt-5.5"]);
+    assert.deepEqual(closedModels, ["deepseek-chat"]);
+    assert.equal(calls.filter((call) => call.method === "initialize").length, 2);
+    assert.deepEqual(calls.filter((call) => call.method === "turn/start").map((call) => call.args.model), ["deepseek-chat", "gpt-5.5"]);
+  } finally {
+    await rm(fakeCodex.root, { recursive: true, force: true });
+    await rm(codexHome, { recursive: true, force: true });
+  }
+});
+
 test("Code Agent Keil gateway prompt is not blocked by M3 IO intent guard", async () => {
   const calls = [];
   let providerCalled = false;
diff --git a/internal/cloud/codex-stdio-session.mjs b/internal/cloud/codex-stdio-session.mjs
index 568ab6e2..b2002938 100644
--- a/internal/cloud/codex-stdio-session.mjs
+++ b/internal/cloud/codex-stdio-session.mjs
@@ -112,6 +112,7 @@ export function createCodexStdioSessionManager(options = {}) {
   const sessions = new Map();
   const conversations = new Map();
   let rpcClient = options.rpcClient ?? null;
+  let rpcClientSignature = options.rpcClient ? "injected" : null;
   let rpcStartedAt = null;
   let rpcInitialized = false;
   let protocolProbe = null;
@@ -964,18 +965,30 @@ export function createCodexStdioSessionManager(options = {}) {
   }
 
   async function ensureRpcClient({ env, availability, timeoutMs } = {}) {
-    if (rpcClient && typeof rpcClient.startTurn === "function") return rpcClient;
+    const args = codexAppServerArgs(env);
+    const childEnv = childProcessEnv(env);
+    const nextSignature = rpcClientConfigSignature({ availability, args, childEnv });
+    if (rpcClient && typeof rpcClient.startTurn === "function" && rpcClientSignature === nextSignature) return rpcClient;
+    if (rpcClient && rpcClientSignature !== nextSignature && typeof rpcClient.close === "function") {
+      rpcClient.close();
+    }
+    if (rpcClientSignature !== nextSignature) {
+      rpcClient = null;
+      rpcInitialized = false;
+      rpcClientSignature = null;
+    }
     rpcClient = options.createRpcClient
       ? await options.createRpcClient({ env, availability })
       : createCodexAppServerJsonLineClient({
           command: availability.command,
-          args: codexAppServerArgs(env),
-          env: childProcessEnv(env),
+          args,
+          env: childEnv,
           cwd: availability.workspace
         });
     if (typeof rpcClient.initialize === "function") {
       await rpcClient.initialize(effectiveTimeout(timeoutMs));
     }
+    rpcClientSignature = nextSignature;
     rpcInitialized = true;
     rpcStartedAt = timestampFor(nowDefault);
     return rpcClient;
@@ -3550,6 +3563,15 @@ function codexProviderNoProxyEntries(env = process.env) {
   }
 }
 
+function rpcClientConfigSignature({ availability, args = [], childEnv = {} } = {}) {
+  return JSON.stringify({
+    command: availability?.command ?? null,
+    workspace: availability?.workspace ?? null,
+    codexHome: childEnv.CODEX_HOME ?? null,
+    args
+  });
+}
+
 function mergeNoProxy(...parts) {
   const entries = [];
   const seen = new Set();