Feature: Add local OpenAI-compatible model discovery to /model (#201)

* Add local OpenAI-compatible model discovery to /model

* Guard local OpenAI model discovery from Codex routing

* Preserve remote OpenAI Codex alias behavior

src/utils/model/modelOptions.ts

@@ -1,5 +1,6 @@
 // biome-ignore-all assist/source/organizeImports: internal-only import markers must not be reordered
 import { getInitialMainLoopModel } from '../../bootstrap/state.js'
+import { getAdditionalModelOptionsCacheScope } from '../../services/api/providerConfig.js'
 import {
   isClaudeAISubscriber,
   isMaxSubscriber,
@@ -44,6 +45,25 @@ export type ModelOption = {
   descriptionForModel?: string
 }
 
+function getScopedAdditionalModelOptions(): ModelOption[] {
+  const config = getGlobalConfig()
+  const activeScope = getAdditionalModelOptionsCacheScope()
+
+  if (!activeScope) {
+    return []
+  }
+
+  if (config.additionalModelOptionsCacheScope !== undefined) {
+    return config.additionalModelOptionsCacheScope === activeScope
+      ? (config.additionalModelOptionsCache ?? [])
+      : []
+  }
+
+  return activeScope === 'firstParty'
+    ? (config.additionalModelOptionsCache ?? [])
+    : []
+}
+
 export function getDefaultOptionForUser(fastMode = false): ModelOption {
   if (process.env.USER_TYPE === 'ant') {
     const currentModel = renderDefaultModelSetting(
@@ -408,6 +428,16 @@ function getModelOptionsBase(fastMode = false): ModelOption[] {
     return standardOptions
   }
 
+  if (getAdditionalModelOptionsCacheScope()?.startsWith('openai:')) {
+    const activeOpenAIOptions = getActiveOpenAIModelOptionsCache()
+    return [
+      getDefaultOptionForUser(fastMode),
+      ...(activeOpenAIOptions.length > 0
+        ? activeOpenAIOptions
+        : getScopedAdditionalModelOptions()),
+    ]
+  }
+
   // PAYG 1P API: Default (Sonnet) + Sonnet 1M + Opus 4.6 + Opus 1M + Haiku
   if (getAPIProvider() === 'firstParty') {
     const payg1POptions = [getDefaultOptionForUser(fastMode)]
@@ -566,13 +596,8 @@ export function getModelOptions(fastMode = false): ModelOption[] {
     })
   }
 
-  const additionalOptions =
-    getAPIProvider() === 'openai'
-      ? getActiveOpenAIModelOptionsCache()
-      : getGlobalConfig().additionalModelOptionsCache ?? []
-
-  // Append additional model options fetched during bootstrap/endpoints.
-  for (const opt of additionalOptions) {
+  // Append additional model options fetched during bootstrap
+  for (const opt of getScopedAdditionalModelOptions()) {
     if (!options.some(existing => existing.value === opt.value)) {
       options.push(opt)
     }

src/utils/model/providers.test.ts

@@ -7,6 +7,9 @@ const originalEnv = {
   CLAUDE_CODE_USE_BEDROCK: process.env.CLAUDE_CODE_USE_BEDROCK,
   CLAUDE_CODE_USE_VERTEX: process.env.CLAUDE_CODE_USE_VERTEX,
   CLAUDE_CODE_USE_FOUNDRY: process.env.CLAUDE_CODE_USE_FOUNDRY,
+  OPENAI_BASE_URL: process.env.OPENAI_BASE_URL,
+  OPENAI_API_BASE: process.env.OPENAI_API_BASE,
+  OPENAI_MODEL: process.env.OPENAI_MODEL,
 }
 
 afterEach(() => {
@@ -16,6 +19,9 @@ afterEach(() => {
   process.env.CLAUDE_CODE_USE_BEDROCK = originalEnv.CLAUDE_CODE_USE_BEDROCK
   process.env.CLAUDE_CODE_USE_VERTEX = originalEnv.CLAUDE_CODE_USE_VERTEX
   process.env.CLAUDE_CODE_USE_FOUNDRY = originalEnv.CLAUDE_CODE_USE_FOUNDRY
+  process.env.OPENAI_BASE_URL = originalEnv.OPENAI_BASE_URL
+  process.env.OPENAI_API_BASE = originalEnv.OPENAI_API_BASE
+  process.env.OPENAI_MODEL = originalEnv.OPENAI_MODEL
 })
 
 async function importFreshProvidersModule() {
@@ -29,6 +35,9 @@ function clearProviderEnv(): void {
   delete process.env.CLAUDE_CODE_USE_BEDROCK
   delete process.env.CLAUDE_CODE_USE_VERTEX
   delete process.env.CLAUDE_CODE_USE_FOUNDRY
+  delete process.env.OPENAI_BASE_URL
+  delete process.env.OPENAI_API_BASE
+  delete process.env.OPENAI_MODEL
 }
 
 test('first-party provider keeps Anthropic account setup flow enabled', () => {
@@ -69,3 +78,29 @@ test('GEMINI takes precedence over GitHub when both are set', async () => {
 
   expect(getAPIProvider()).toBe('gemini')
 })
+
+test('explicit local openai-compatible base URLs stay on the openai provider', () => {
+  clearProviderEnv()
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_BASE_URL = 'http://127.0.0.1:8080/v1'
+  process.env.OPENAI_MODEL = 'gpt-5.4'
+
+  expect(getAPIProvider()).toBe('openai')
+})
+
+test('codex aliases still resolve to the codex provider without a non-codex base URL', () => {
+  clearProviderEnv()
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_MODEL = 'codexplan'
+
+  expect(getAPIProvider()).toBe('codex')
+})
+
+test('official OpenAI base URLs now keep provider detection on openai for aliases', () => {
+  clearProviderEnv()
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_BASE_URL = 'https://api.openai.com/v1'
+  process.env.OPENAI_MODEL = 'gpt-5.4'
+
+  expect(getAPIProvider()).toBe('openai')
+})

src/utils/model/providers.ts

@@ -1,5 +1,5 @@
 import type { AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS } from '../../services/analytics/index.js'
-import { isCodexAlias } from '../../services/api/providerConfig.js'
+import { shouldUseCodexTransport } from '../../services/api/providerConfig.js'
 import { isEnvTruthy } from '../envUtils.js'
 
 export type APIProvider =
@@ -34,11 +34,10 @@ export function usesAnthropicAccountFlow(): boolean {
   return getAPIProvider() === 'firstParty'
 }
 function isCodexModel(): boolean {
-  const model = (process.env.OPENAI_MODEL || '').trim()
-  if (!model) return false
-  // Delegate to the canonical alias table in providerConfig to keep
-  // the two Codex detection systems (provider type + transport) in sync.
-  return isCodexAlias(model)
+  return shouldUseCodexTransport(
+    process.env.OPENAI_MODEL || '',
+    process.env.OPENAI_BASE_URL ?? process.env.OPENAI_API_BASE,
+  )
 }
 
 export function getAPIProviderForStatsig(): AnalyticsMetadata_I_VERIFIED_THIS_IS_NOT_CODE_OR_FILEPATHS {