fix: update Codex executor for gpt-5.3-codex support

Co-authored-by: Cursor <cursoragent@cursor.com>

open-sse/config/constants.js

@@ -39,9 +39,8 @@ export const PROVIDERS = {
     baseUrl: "https://chatgpt.com/backend-api/codex/responses",
     format: "openai-responses", // Use OpenAI Responses API format (reuse translator)
     headers: {
-      "Version": "0.92.0",
+      "originator": "codex-cli",
-      "Openai-Beta": "responses=experimental",
+      "User-Agent": "codex-cli/1.0.18 (macOS; arm64)"
-      "User-Agent": "codex-cli/0.92.0 (Windows 10.0.26100; x64)"
     },
     // OpenAI OAuth configuration
     clientId: "app_EMoamEEZ73f0CkXaXp7hrann",

open-sse/executors/codex.js

@@ -11,10 +11,27 @@ export class CodexExecutor extends BaseExecutor {
     super("codex", PROVIDERS.codex);
   }
 
+  /**
+   * Override headers to add session_id per request
+   */
+  buildHeaders(credentials, stream = true) {
+    const headers = super.buildHeaders(credentials, stream);
+    headers["session_id"] = `${Date.now()}-${Math.random().toString(36).slice(2, 11)}`;
+    return headers;
+  }
+
   /**
    * Transform request before sending - inject default instructions if missing
    */
   transformRequest(model, body, stream, credentials) {
+    // Ensure input is present and non-empty (Codex API rejects empty input)
+    if (!body.input || (Array.isArray(body.input) && body.input.length === 0)) {
+      body.input = [{ type: "message", role: "user", content: [{ type: "input_text", text: "..." }] }];
+    }
+
+    // Ensure streaming is enabled (Codex API requires it)
+    body.stream = true;
+
     // If no instructions provided, inject default Codex instructions
     if (!body.instructions || body.instructions.trim() === "") {
       body.instructions = CODEX_DEFAULT_INSTRUCTIONS;
@@ -39,10 +56,17 @@ export class CodexExecutor extends BaseExecutor {
     // Priority: explicit reasoning.effort > reasoning_effort param > model suffix > default (medium)
     if (!body.reasoning) {
       const effort = body.reasoning_effort || modelEffort || 'medium';
-      body.reasoning = { effort };
+      body.reasoning = { effort, summary: "auto" };
+    } else if (!body.reasoning.summary) {
+      body.reasoning.summary = "auto";
     }
     delete body.reasoning_effort;
 
+    // Include reasoning encrypted content (required by Codex backend for reasoning models)
+    if (body.reasoning && body.reasoning.effort && body.reasoning.effort !== 'none') {
+      body.include = ["reasoning.encrypted_content"];
+    }
+
     // Remove unsupported parameters for Codex API
     delete body.temperature;
     delete body.top_p;

open-sse/translator/response/openai-responses.js

@@ -368,7 +368,7 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
         id: state.chatId || `chatcmpl-${Date.now()}`,
         object: "chat.completion.chunk",
         created: state.created || Math.floor(Date.now() / 1000),
-        model: state.model || "gpt-4",
+        model: state.model || "unknown",
         choices: [{
           index: 0,
           delta: {},
@@ -401,7 +401,7 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
       id: state.chatId,
       object: "chat.completion.chunk",
       created: state.created,
-      model: state.model || "gpt-4",
+      model: state.model || "unknown",
       choices: [{
         index: 0,
         delta: { content: delta },
@@ -424,7 +424,7 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
       id: state.chatId,
       object: "chat.completion.chunk",
       created: state.created,
-      model: state.model || "gpt-4",
+      model: state.model || "unknown",
       choices: [{
         index: 0,
         delta: {
@@ -452,7 +452,7 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
       id: state.chatId,
       object: "chat.completion.chunk",
       created: state.created,
-      model: state.model || "gpt-4",
+      model: state.model || "unknown",
       choices: [{
         index: 0,
         delta: {
@@ -511,7 +511,7 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
         id: state.chatId,
         object: "chat.completion.chunk",
         created: state.created,
-        model: state.model || "gpt-4",
+        model: state.model || "unknown",
         choices: [{
           index: 0,
           delta: {},
@@ -529,6 +529,32 @@ export function openaiResponsesToOpenAIResponse(chunk, state) {
     return null;
   }
 
+  // Error events from Responses API (e.g. model_not_found)
+  if (eventType === "error" || eventType === "response.failed") {
+    // Avoid emitting duplicate errors (error + response.failed arrive back-to-back)
+    if (state.finishReasonSent) return null;
+
+    const error = data.error || data.response?.error;
+    if (error) {
+      state.error = error;
+      state.finishReasonSent = true;
+
+      // Surface the error as an OpenAI-compatible error chunk
+      return {
+        id: state.chatId || `chatcmpl-${Date.now()}`,
+        object: "chat.completion.chunk",
+        created: state.created || Math.floor(Date.now() / 1000),
+        model: state.model || "unknown",
+        choices: [{
+          index: 0,
+          delta: { content: `[Error] ${error.message || JSON.stringify(error)}` },
+          finish_reason: "stop"
+        }]
+      };
+    }
+    return null;
+  }
+
   // Reasoning events (convert to content or skip)
   if (eventType === "response.reasoning_summary_text.delta") {
     // Optionally include reasoning as content, or skip

open-sse/utils/stream.js

@@ -49,7 +49,7 @@ export function createSSEStream(options = {}) {
   let buffer = "";
   let usage = null;
 
-  const state = mode === STREAM_MODE.TRANSLATE ? { ...initState(sourceFormat), provider, toolNameMap } : null;
+  const state = mode === STREAM_MODE.TRANSLATE ? { ...initState(sourceFormat), provider, toolNameMap, model } : null;
 
   let totalContentLength = 0;
   let accumulatedContent = "";

src/app/api/providers/[id]/test/route.js

@@ -17,10 +17,7 @@ const OAUTH_TEST_CONFIG = {
     checkExpiry: true,
   },
   codex: {
-    url: "https://api.openai.com/v1/models",
+    checkExpiry: true,
-    method: "GET",
-    authHeader: "Authorization",
-    authPrefix: "Bearer ",
     refreshable: true,
   },
   "gemini-cli": {