diff --git a/src/commands/provider.ts b/src/commands/provider.ts
index 19b19c021..eae2e2dd2 100644
--- a/src/commands/provider.ts
+++ b/src/commands/provider.ts
@@ -63,6 +63,7 @@ const call: LocalCommandCall = async (args, context) => {
   const validProviders = [
     'anthropic',
     'openai',
+    'codex',
     'gemini',
     'grok',
     'bedrock',
@@ -120,10 +121,23 @@ const call: LocalCommandCall = async (args, context) => {
     }
   }
 
+  // Check env vars when switching to codex (including settings.env)
+  if (arg === 'codex') {
+    const mergedEnv = getMergedEnv()
+    const hasKey = !!mergedEnv.CODEX_API_KEY
+    if (!hasKey) {
+      updateSettingsForSource('userSettings', { modelType: 'codex' })
+      return {
+        type: 'text',
+        value: `Switched to Codex provider.\nWarning: Missing env var: CODEX_API_KEY\nConfigure it via /login (ChatGPT Subscription) or set manually.`,
+      }
+    }
+  }
+
   // Handle different provider types
   // - 'anthropic', 'openai', 'gemini' are stored in settings.json (persistent)
   // - 'bedrock', 'vertex', 'foundry' are env-only (do NOT touch settings.json)
-  if (arg === 'anthropic' || arg === 'openai' || arg === 'gemini' || arg === 'grok') {
+  if (arg === 'anthropic' || arg === 'openai' || arg === 'codex' || arg === 'gemini' || arg === 'grok') {
     // Clear any cloud provider env vars to avoid conflicts
     delete process.env.CLAUDE_CODE_USE_BEDROCK
     delete process.env.CLAUDE_CODE_USE_VERTEX
@@ -131,7 +145,7 @@ const call: LocalCommandCall = async (args, context) => {
     delete process.env.CLAUDE_CODE_USE_OPENAI
     delete process.env.CLAUDE_CODE_USE_GEMINI
     delete process.env.CLAUDE_CODE_USE_GROK
-    // Update settings.json
+    delete process.env.CLAUDE_CODE_USE_CODEX
     updateSettingsForSource('userSettings', { modelType: arg })
     // Ensure settings.env gets applied to process.env
     applyConfigEnvironmentVariables()
@@ -157,9 +171,9 @@ const provider = {
   type: 'local',
   name: 'provider',
   description:
-    'Switch API provider (anthropic/openai/gemini/grok/bedrock/vertex/foundry)',
+    'Switch API provider (anthropic/openai/codex/gemini/grok/bedrock/vertex/foundry)',
   aliases: ['api'],
-  argumentHint: '[anthropic|openai|gemini|grok|bedrock|vertex|foundry|unset]',
+  argumentHint: '[anthropic|openai|codex|gemini|grok|bedrock|vertex|foundry|unset]',
   supportsNonInteractive: true,
   load: () => Promise.resolve({ call }),
 } satisfies Command
diff --git a/src/utils/managedEnvConstants.ts b/src/utils/managedEnvConstants.ts
index d1976c114..688e794c5 100644
--- a/src/utils/managedEnvConstants.ts
+++ b/src/utils/managedEnvConstants.ts
@@ -23,6 +23,7 @@ const PROVIDER_MANAGED_ENV_VARS = new Set([
   'CLAUDE_CODE_USE_VERTEX',
   'CLAUDE_CODE_USE_FOUNDRY',
   'CLAUDE_CODE_USE_GEMINI',
+  'CLAUDE_CODE_USE_CODEX',
   // Endpoint config (base URLs, project/resource identifiers)
   'ANTHROPIC_BASE_URL',
   'ANTHROPIC_BEDROCK_BASE_URL',
@@ -31,6 +32,7 @@ const PROVIDER_MANAGED_ENV_VARS = new Set([
   'ANTHROPIC_FOUNDRY_RESOURCE',
   'ANTHROPIC_VERTEX_PROJECT_ID',
   'GEMINI_BASE_URL',
+  'CODEX_BASE_URL',
   // Region routing (per-model VERTEX_REGION_CLAUDE_* handled by prefix below)
   'CLOUD_ML_REGION',
   // Auth
@@ -43,6 +45,7 @@ const PROVIDER_MANAGED_ENV_VARS = new Set([
   'CLAUDE_CODE_SKIP_VERTEX_AUTH',
   'CLAUDE_CODE_SKIP_FOUNDRY_AUTH',
   'GEMINI_API_KEY',
+  'CODEX_API_KEY',
   // Model defaults — often set to provider-specific ID formats
   'ANTHROPIC_MODEL',
   'ANTHROPIC_DEFAULT_HAIKU_MODEL',
@@ -92,6 +95,17 @@ const PROVIDER_MANAGED_ENV_VARS = new Set([
   'GEMINI_DEFAULT_SONNET_MODEL_DESCRIPTION',
   'GEMINI_DEFAULT_SONNET_MODEL_NAME',
   'GEMINI_DEFAULT_SONNET_MODEL_SUPPORTED_CAPABILITIES',
+  // Codex provider specific
+  'CODEX_BASE_URL',
+  'CODEX_API_KEY',
+  'CODEX_MODEL',
+  'CODEX_DEFAULT_HAIKU_MODEL',
+  'CODEX_DEFAULT_SONNET_MODEL',
+  'CODEX_DEFAULT_OPUS_MODEL',
+  'CODEX_IMGBB_API_KEY',
+  'CODEX_LOGIN_METHOD',
+  'CODEX_ACCESS_TOKEN',
+  'CODEX_REFRESH_TOKEN',
 ])
 
 const PROVIDER_MANAGED_ENV_PREFIXES = [
@@ -201,6 +215,7 @@ export const SAFE_ENV_VARS = new Set([
   'CLAUDE_CODE_USE_FOUNDRY',
   'CLAUDE_CODE_USE_GEMINI',
   'CLAUDE_CODE_USE_VERTEX',
+  'CLAUDE_CODE_USE_CODEX',
   'GEMINI_MODEL',
   'GEMINI_SMALL_FAST_MODEL',
   'GEMINI_DEFAULT_HAIKU_MODEL',
@@ -215,6 +230,11 @@ export const SAFE_ENV_VARS = new Set([
   'GEMINI_DEFAULT_SONNET_MODEL_DESCRIPTION',
   'GEMINI_DEFAULT_SONNET_MODEL_NAME',
   'GEMINI_DEFAULT_SONNET_MODEL_SUPPORTED_CAPABILITIES',
+  // Codex provider specific
+  'CODEX_DEFAULT_HAIKU_MODEL',
+  'CODEX_DEFAULT_SONNET_MODEL',
+  'CODEX_DEFAULT_OPUS_MODEL',
+  'CODEX_IMGBB_API_KEY',
   'DISABLE_AUTOUPDATER',
   'DISABLE_BUG_COMMAND',
   'DISABLE_COST_WARNINGS',
diff --git a/src/utils/model/configs.ts b/src/utils/model/configs.ts
index 58d157d9c..3a1bbf617 100644
--- a/src/utils/model/configs.ts
+++ b/src/utils/model/configs.ts
@@ -13,6 +13,7 @@ export const CLAUDE_3_7_SONNET_CONFIG = {
   foundry: 'claude-3-7-sonnet',
   openai: 'claude-3-7-sonnet-20250219',
   gemini: 'claude-3-7-sonnet-20250219',
+  codex: 'claude-3-7-sonnet-20250219',
   grok: 'claude-3-7-sonnet-20250219',
 } as const satisfies ModelConfig
 
@@ -23,6 +24,7 @@ export const CLAUDE_3_5_V2_SONNET_CONFIG = {
   foundry: 'claude-3-5-sonnet',
   openai: 'claude-3-5-sonnet-20241022',
   gemini: 'claude-3-5-sonnet-20241022',
+  codex: 'claude-3-5-sonnet-20241022',
   grok: 'claude-3-5-sonnet-20241022',
 } as const satisfies ModelConfig
 
@@ -33,6 +35,7 @@ export const CLAUDE_3_5_HAIKU_CONFIG = {
   foundry: 'claude-3-5-haiku',
   openai: 'claude-3-5-haiku-20241022',
   gemini: 'claude-3-5-haiku-20241022',
+  codex: 'claude-3-5-haiku-20241022',
   grok: 'claude-3-5-haiku-20241022',
 } as const satisfies ModelConfig
 
@@ -43,6 +46,7 @@ export const CLAUDE_HAIKU_4_5_CONFIG = {
   foundry: 'claude-haiku-4-5',
   openai: 'claude-haiku-4-5-20251001',
   gemini: 'claude-haiku-4-5-20251001',
+  codex: 'claude-haiku-4-5-20251001',
   grok: 'claude-haiku-4-5-20251001',
 } as const satisfies ModelConfig
 
@@ -53,6 +57,7 @@ export const CLAUDE_SONNET_4_CONFIG = {
   foundry: 'claude-sonnet-4',
   openai: 'claude-sonnet-4-20250514',
   gemini: 'claude-sonnet-4-20250514',
+  codex: 'claude-sonnet-4-20250514',
   grok: 'claude-sonnet-4-20250514',
 } as const satisfies ModelConfig
 
@@ -63,6 +68,7 @@ export const CLAUDE_SONNET_4_5_CONFIG = {
   foundry: 'claude-sonnet-4-5',
   openai: 'claude-sonnet-4-5-20250929',
   gemini: 'claude-sonnet-4-5-20250929',
+  codex: 'claude-sonnet-4-5-20250929',
   grok: 'claude-sonnet-4-5-20250929',
 } as const satisfies ModelConfig
 
@@ -73,6 +79,7 @@ export const CLAUDE_OPUS_4_CONFIG = {
   foundry: 'claude-opus-4',
   openai: 'claude-opus-4-20250514',
   gemini: 'claude-opus-4-20250514',
+  codex: 'claude-opus-4-20250514',
   grok: 'claude-opus-4-20250514',
 } as const satisfies ModelConfig
 
@@ -83,6 +90,7 @@ export const CLAUDE_OPUS_4_1_CONFIG = {
   foundry: 'claude-opus-4-1',
   openai: 'claude-opus-4-1-20250805',
   gemini: 'claude-opus-4-1-20250805',
+  codex: 'claude-opus-4-1-20250805',
   grok: 'claude-opus-4-1-20250805',
 } as const satisfies ModelConfig
 
@@ -93,6 +101,7 @@ export const CLAUDE_OPUS_4_5_CONFIG = {
   foundry: 'claude-opus-4-5',
   openai: 'claude-opus-4-5-20251101',
   gemini: 'claude-opus-4-5-20251101',
+  codex: 'claude-opus-4-5-20251101',
   grok: 'claude-opus-4-5-20251101',
 } as const satisfies ModelConfig
 
@@ -103,6 +112,7 @@ export const CLAUDE_OPUS_4_6_CONFIG = {
   foundry: 'claude-opus-4-6',
   openai: 'claude-opus-4-6',
   gemini: 'claude-opus-4-6',
+  codex: 'claude-opus-4-6',
   grok: 'claude-opus-4-6',
 } as const satisfies ModelConfig
 
@@ -113,6 +123,7 @@ export const CLAUDE_OPUS_4_7_CONFIG = {
   foundry: 'claude-opus-4-7',
   openai: 'claude-opus-4-7',
   gemini: 'claude-opus-4-7',
+  codex: 'claude-opus-4-7',
   grok: 'claude-opus-4-7',
 } as const satisfies ModelConfig
 
@@ -123,6 +134,7 @@ export const CLAUDE_SONNET_4_6_CONFIG = {
   foundry: 'claude-sonnet-4-6',
   openai: 'claude-sonnet-4-6',
   gemini: 'claude-sonnet-4-6',
+  codex: 'claude-sonnet-4-6',
   grok: 'claude-sonnet-4-6',
 } as const satisfies ModelConfig
 
diff --git a/src/utils/model/providers.ts b/src/utils/model/providers.ts
index 79572d42e..d04f88f70 100644
--- a/src/utils/model/providers.ts
+++ b/src/utils/model/providers.ts
@@ -8,12 +8,14 @@ export type APIProvider =
   | 'vertex'
   | 'foundry'
   | 'openai'
+  | 'codex'
   | 'gemini'
   | 'grok'
 
 export function getAPIProvider(): APIProvider {
   const modelType = getInitialSettings().modelType
   if (modelType === 'openai') return 'openai'
+  if (modelType === 'codex') return 'codex'
   if (modelType === 'gemini') return 'gemini'
   if (modelType === 'grok') return 'grok'
 
@@ -22,6 +24,7 @@ export function getAPIProvider(): APIProvider {
   if (isEnvTruthy(process.env.CLAUDE_CODE_USE_FOUNDRY)) return 'foundry'
 
   if (isEnvTruthy(process.env.CLAUDE_CODE_USE_OPENAI)) return 'openai'
+  if (isEnvTruthy(process.env.CLAUDE_CODE_USE_CODEX)) return 'codex'
   if (isEnvTruthy(process.env.CLAUDE_CODE_USE_GEMINI)) return 'gemini'
   if (isEnvTruthy(process.env.CLAUDE_CODE_USE_GROK)) return 'grok'
 
diff --git a/src/utils/status.tsx b/src/utils/status.tsx
index b4cb087c2..f45a1436e 100644
--- a/src/utils/status.tsx
+++ b/src/utils/status.tsx
@@ -342,6 +342,7 @@ export function buildAPIProviderProperties(): Property[] {
       gemini: 'Gemini API',
       grok: 'Grok API',
       openai: 'OpenAI API',
+      codex: 'Codex API',
     }[apiProvider]
     properties.push({
       label: 'API provider',