feat: Add support for default model per provider

codex-cli/src/cli.tsx

@@ -43,6 +43,7 @@ import {
 } from "./utils/get-api-key";
 import { createInputItem } from "./utils/input-utils";
 import { initLogger } from "./utils/logger/log";
+import { getModelForProvider } from "./utils/model-selection";
 import { isModelSupportedForResponses } from "./utils/model-utils.js";
 import { parseToolCall } from "./utils/parsers";
 import { onExit, setInkRenderer } from "./utils/terminal";
@@ -289,10 +290,16 @@ let config = loadConfig(undefined, undefined, {
 // via the `--history` flag. Therefore it must be declared with `let` rather
 // than `const`.
 let prompt = cli.input[0];
-const model = cli.flags.model ?? config.model;
-const imagePaths = cli.flags.image;
 const provider = cli.flags.provider ?? config.provider ?? "openai";
 
+// Get the appropriate model for the selected provider
+const model = getModelForProvider(config, {
+  model: cli.flags.model,
+  provider,
+});
+
+const imagePaths = cli.flags.image;
+
 const client = {
   issuer: "https://auth.openai.com",
   client_id: "app_EMoamEEZ73f0CkXaXp7hrann",

codex-cli/src/components/chat/terminal-chat.tsx

@@ -639,11 +639,17 @@ export default function TerminalChat({
                 prev && newModel !== model ? null : prev,
               );
 
-              // Save model to config
+              // Save model to config and update the default model for this provider
+              const providerDefaultModels = {
+                ...(config.providerDefaultModels || {}),
+                [provider]: newModel,
+              };
+
               saveConfig({
                 ...config,
                 model: newModel,
                 provider: provider,
+                providerDefaultModels,
               });
 
               setItems((prev) => [
@@ -674,7 +680,8 @@ export default function TerminalChat({
               setLoading(false);
 
               // Select default model for the new provider.
-              const defaultModel = model;
+              const defaultModel =
+                config.providerDefaultModels?.[newProvider] || model;
 
               // Save provider to config.
               const updatedConfig = {

codex-cli/src/utils/config.ts

@@ -149,7 +149,18 @@ export type StoredConfig = {
   /** Disable server-side response storage (send full transcript each request) */
   disableResponseStorage?: boolean;
   flexMode?: boolean;
-  providers?: Record<string, { name: string; baseURL: string; envKey: string }>;
+  providers?: Record<
+    string,
+    {
+      name: string;
+      baseURL: string;
+      envKey: string;
+      /** Default model to use for this provider */
+      defaultModel?: string;
+    }
+  >;
+  /** Map of provider IDs to their default models */
+  providerDefaultModels?: Record<string, string>;
   history?: {
     maxSize?: number;
     saveHistory?: boolean;
@@ -202,7 +213,18 @@ export type AppConfig = {
 
   /** Enable the "flex-mode" processing mode for supported models (o3, o4-mini) */
   flexMode?: boolean;
-  providers?: Record<string, { name: string; baseURL: string; envKey: string }>;
+  providers?: Record<
+    string,
+    {
+      name: string;
+      baseURL: string;
+      envKey: string;
+      /** Default model to use for this provider */
+      defaultModel?: string;
+    }
+  >;
+  /** Map of provider IDs to their default models */
+  providerDefaultModels?: Record<string, string>;
   history?: {
     maxSize: number;
     saveHistory: boolean;
@@ -439,6 +461,7 @@ export const loadConfig = (
     disableResponseStorage: storedConfig.disableResponseStorage === true,
     reasoningEffort: storedConfig.reasoningEffort,
     fileOpener: storedConfig.fileOpener,
+    providerDefaultModels: storedConfig.providerDefaultModels,
   };
 
   // -----------------------------------------------------------------------
@@ -560,6 +583,7 @@ export const saveConfig = (
     disableResponseStorage: config.disableResponseStorage,
     flexMode: config.flexMode,
     reasoningEffort: config.reasoningEffort,
+    providerDefaultModels: config.providerDefaultModels,
   };
 
   // Add history settings if they exist

codex-cli/src/utils/model-selection.ts

@@ -0,0 +1,34 @@
+import type { AppConfig } from "./config";
+
+/**
+ * Get the appropriate model for the selected provider
+ *
+ * @param config The application configuration
+ * @param cliFlags The CLI flags containing model and provider information
+ * @returns The model to use
+ */
+export function getModelForProvider(
+  config: AppConfig,
+  cliFlags: { model?: string; provider?: string },
+): string {
+  // CLI model flag takes precedence
+  if (cliFlags.model) {
+    return cliFlags.model;
+  }
+
+  // If provider is specified and there's a default model for it in providerDefaultModels, use that
+  if (cliFlags.provider && config.providerDefaultModels?.[cliFlags.provider]) {
+    return config.providerDefaultModels[cliFlags.provider] as string;
+  }
+
+  // If provider is specified and there's a provider config with defaultModel, use that
+  if (
+    cliFlags.provider &&
+    config.providers?.[cliFlags.provider]?.defaultModel
+  ) {
+    return config.providers[cliFlags.provider]?.defaultModel as string;
+  }
+
+  // Fall back to global default model
+  return config.model;
+}