diff --git a/server/openai-codex.js b/server/openai-codex.js
index 5a7a9007..825ee179 100644
--- a/server/openai-codex.js
+++ b/server/openai-codex.js
@@ -143,7 +143,7 @@ function transformCodexEvent(event) {
     case 'thread.started':
       return {
         type: 'thread_started',
-        threadId: event.id
+        threadId: event.thread_id || event.id
       };
 
     case 'error':
@@ -207,7 +207,8 @@ export async function queryCodex(command, options = {}, ws) {
 
   let codex;
   let thread;
-  let currentSessionId = sessionId;
+  let capturedSessionId = sessionId;
+  let sessionCreatedSent = false;
   let terminalFailure = null;
   const abortController = new AbortController();
 
@@ -231,20 +232,27 @@ export async function queryCodex(command, options = {}, ws) {
       thread = codex.startThread(threadOptions);
     }
 
-    // Get the thread ID
-    currentSessionId = thread.id || sessionId || `codex-${Date.now()}`;
+    console.log(`[Codex] Started thread, sandboxMode: ${sandboxMode}, approvalPolicy: ${approvalPolicy}`);
 
-    // Track the session
-    activeCodexSessions.set(currentSessionId, {
-      thread,
-      codex,
-      status: 'running',
-      abortController,
-      startedAt: new Date().toISOString()
-    });
+    const registerSession = (id) => {
+      if (!id) {
+        return;
+      }
+      if (!activeCodexSessions.has(id)) {
+        activeCodexSessions.set(id, {
+          thread,
+          codex,
+          status: 'running',
+          abortController,
+          startedAt: new Date().toISOString()
+        });
+      }
+    };
 
-    // Send session created event
-    sendMessage(ws, createNormalizedMessage({ kind: 'session_created', newSessionId: currentSessionId, sessionId: currentSessionId, provider: 'codex' }));
+    // Existing sessions can be tracked immediately; new sessions are tracked after thread.started.
+    if (capturedSessionId) {
+      registerSession(capturedSessionId);
+    }
 
     // Execute with streaming
     const streamedTurn = await thread.runStreamed(command, {
@@ -252,11 +260,34 @@ export async function queryCodex(command, options = {}, ws) {
     });
 
     for await (const event of streamedTurn.events) {
+      // Capture thread/session id lazily from the stream (Codex emits this asynchronously).
+      if (event.type === 'thread.started') {
+        const discoveredSessionId = event.thread_id || event.id || null;
+        if (discoveredSessionId && !capturedSessionId) {
+          capturedSessionId = discoveredSessionId;
+          registerSession(capturedSessionId);
+
+          if (ws.setSessionId && typeof ws.setSessionId === 'function') {
+            ws.setSessionId(capturedSessionId);
+          }
+
+          if (!sessionId && !sessionCreatedSent) {
+            sessionCreatedSent = true;
+            sendMessage(ws, createNormalizedMessage({ kind: 'session_created', newSessionId: capturedSessionId, sessionId: capturedSessionId, provider: 'codex' }));
+          }
+        }
+      }
+
       // Check if session was aborted
-      const session = activeCodexSessions.get(currentSessionId);
-      if (!session || session.status === 'aborted') {
+      if (abortController.signal.aborted) {
         break;
       }
+      if (capturedSessionId) {
+        const session = activeCodexSessions.get(capturedSessionId);
+        if (session?.status === 'aborted') {
+          break;
+        }
+      }
 
       if (event.type === 'item.started' || event.type === 'item.updated') {
         continue;
@@ -265,7 +296,7 @@ export async function queryCodex(command, options = {}, ws) {
       const transformed = transformCodexEvent(event);
 
       // Normalize the transformed event into NormalizedMessage(s) via adapter
-      const normalizedMsgs = sessionsService.normalizeMessage('codex', transformed, currentSessionId);
+      const normalizedMsgs = sessionsService.normalizeMessage('codex', transformed, capturedSessionId || sessionId || null);
       for (const msg of normalizedMsgs) {
         sendMessage(ws, msg);
       }
@@ -275,7 +306,7 @@ export async function queryCodex(command, options = {}, ws) {
         notifyRunFailed({
           userId: ws?.userId || null,
           provider: 'codex',
-          sessionId: currentSessionId,
+          sessionId: capturedSessionId || sessionId || null,
           sessionName: sessionSummary,
           error: terminalFailure
         });
@@ -284,24 +315,29 @@ export async function queryCodex(command, options = {}, ws) {
       // Extract and send token usage if available (normalized to match Claude format)
       if (event.type === 'turn.completed' && event.usage) {
         const totalTokens = (event.usage.input_tokens || 0) + (event.usage.output_tokens || 0);
-        sendMessage(ws, createNormalizedMessage({ kind: 'status', text: 'token_budget', tokenBudget: { used: totalTokens, total: 200000 }, sessionId: currentSessionId, provider: 'codex' }));
+        sendMessage(ws, createNormalizedMessage({ kind: 'status', text: 'token_budget', tokenBudget: { used: totalTokens, total: 200000 }, sessionId: capturedSessionId || sessionId || null, provider: 'codex' }));
       }
     }
 
     // Send completion event
     if (!terminalFailure) {
-      sendMessage(ws, createNormalizedMessage({ kind: 'complete', actualSessionId: thread.id, sessionId: currentSessionId, provider: 'codex' }));
+      sendMessage(ws, createNormalizedMessage({
+        kind: 'complete',
+        actualSessionId: capturedSessionId || thread.id || sessionId || null,
+        sessionId: capturedSessionId || sessionId || null,
+        provider: 'codex'
+      }));
       notifyRunStopped({
         userId: ws?.userId || null,
         provider: 'codex',
-        sessionId: currentSessionId,
+        sessionId: capturedSessionId || sessionId || null,
         sessionName: sessionSummary,
         stopReason: 'completed'
       });
     }
 
   } catch (error) {
-    const session = currentSessionId ? activeCodexSessions.get(currentSessionId) : null;
+    const session = capturedSessionId ? activeCodexSessions.get(capturedSessionId) : null;
     const wasAborted =
       session?.status === 'aborted' ||
       error?.name === 'AbortError' ||
@@ -316,12 +352,12 @@ export async function queryCodex(command, options = {}, ws) {
         ? 'Codex CLI is not configured. Please set up authentication first.'
         : error.message;
 
-      sendMessage(ws, createNormalizedMessage({ kind: 'error', content: errorContent, sessionId: currentSessionId, provider: 'codex' }));
+      sendMessage(ws, createNormalizedMessage({ kind: 'error', content: errorContent, sessionId: capturedSessionId || sessionId || null, provider: 'codex' }));
       if (!terminalFailure) {
         notifyRunFailed({
           userId: ws?.userId || null,
           provider: 'codex',
-          sessionId: currentSessionId,
+          sessionId: capturedSessionId || sessionId || null,
           sessionName: sessionSummary,
           error
         });
@@ -330,8 +366,8 @@ export async function queryCodex(command, options = {}, ws) {
 
   } finally {
     // Update session status
-    if (currentSessionId) {
-      const session = activeCodexSessions.get(currentSessionId);
+    if (capturedSessionId) {
+      const session = activeCodexSessions.get(capturedSessionId);
       if (session) {
         session.status = session.status === 'aborted' ? 'aborted' : 'completed';
       }