fix(model): codex/nvidia-nim/minimax now read OPENAI_MODEL env (#815)

getUserSpecifiedModelSetting() decides which env var to consult based on
the active provider. The check included openai and github but omitted
codex, nvidia-nim, and minimax — even though all three use the OpenAI
shim transport and get their model routing via CLAUDE_CODE_USE_OPENAI=1
+ OPENAI_MODEL (set by applyProviderProfileToProcessEnv).

Concrete failure: user switches from Moonshot profile (which persisted
settings.model='kimi-k2.6') to the Codex profile. The new profile
correctly writes OPENAI_MODEL=codexplan + base URL to
chatgpt.com/backend-api/codex. Startup banner reflects Codex / gpt-5.4
correctly. But at request time getUserSpecifiedModelSetting() returns
early for provider='codex' (not in the env-consult list), falls through
to the stale settings.model='kimi-k2.6', and the Codex API rejects:

  API Error 400: "The 'kimi-k2.6' model is not supported when using
  Codex with a ChatGPT account."

Fix: extract an isOpenAIShimProvider flag covering openai|codex|github|
nvidia-nim|minimax — all providers that set OPENAI_MODEL as their model
env var. The Gemini and Mistral branches stay as-is (they use
GEMINI_MODEL / MISTRAL_MODEL).

Five regression tests pin the fix for each OpenAI-shim provider plus
guard tests for openai and github that already worked.

Co-authored-by: OpenClaude <openclaude@gitlawb.com>

src/utils/model/model.openai-shim-providers.test.ts

@@ -0,0 +1,115 @@
+import { afterEach, beforeEach, expect, test } from 'bun:test'
+
+import { saveGlobalConfig } from '../config.js'
+import { getUserSpecifiedModelSetting } from './model.js'
+
+const SAVED_ENV = {
+  CLAUDE_CODE_USE_OPENAI: process.env.CLAUDE_CODE_USE_OPENAI,
+  CLAUDE_CODE_USE_GEMINI: process.env.CLAUDE_CODE_USE_GEMINI,
+  CLAUDE_CODE_USE_GITHUB: process.env.CLAUDE_CODE_USE_GITHUB,
+  CLAUDE_CODE_USE_MISTRAL: process.env.CLAUDE_CODE_USE_MISTRAL,
+  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,
+  NVIDIA_NIM: process.env.NVIDIA_NIM,
+  MINIMAX_API_KEY: process.env.MINIMAX_API_KEY,
+  OPENAI_MODEL: process.env.OPENAI_MODEL,
+  OPENAI_BASE_URL: process.env.OPENAI_BASE_URL,
+  CODEX_API_KEY: process.env.CODEX_API_KEY,
+  CHATGPT_ACCOUNT_ID: process.env.CHATGPT_ACCOUNT_ID,
+}
+
+function restoreEnv(key: keyof typeof SAVED_ENV): void {
+  if (SAVED_ENV[key] === undefined) {
+    delete process.env[key]
+  } else {
+    process.env[key] = SAVED_ENV[key]
+  }
+}
+
+beforeEach(() => {
+  delete process.env.CLAUDE_CODE_USE_OPENAI
+  delete process.env.CLAUDE_CODE_USE_GEMINI
+  delete process.env.CLAUDE_CODE_USE_GITHUB
+  delete process.env.CLAUDE_CODE_USE_MISTRAL
+  delete process.env.CLAUDE_CODE_USE_BEDROCK
+  delete process.env.CLAUDE_CODE_USE_VERTEX
+  delete process.env.CLAUDE_CODE_USE_FOUNDRY
+  delete process.env.NVIDIA_NIM
+  delete process.env.MINIMAX_API_KEY
+  delete process.env.OPENAI_MODEL
+  delete process.env.OPENAI_BASE_URL
+  delete process.env.CODEX_API_KEY
+  delete process.env.CHATGPT_ACCOUNT_ID
+  saveGlobalConfig(current => ({
+    ...current,
+    model: undefined,
+  }))
+})
+
+afterEach(() => {
+  for (const key of Object.keys(SAVED_ENV) as Array<keyof typeof SAVED_ENV>) {
+    restoreEnv(key)
+  }
+  saveGlobalConfig(current => ({
+    ...current,
+    model: undefined,
+  }))
+})
+
+test('codex provider reads OPENAI_MODEL, not stale settings.model', () => {
+  // Regression: switching from Moonshot (settings.model='kimi-k2.6' persisted
+  // from that session) to the Codex profile. Codex profile correctly sets
+  // OPENAI_MODEL=codexplan + base URL to chatgpt.com/backend-api/codex.
+  // getUserSpecifiedModelSetting previously ignored env for 'codex' provider
+  // and returned settings.model='kimi-k2.6', causing Codex's API to reject
+  // the request: "The 'kimi-k2.6' model is not supported when using Codex".
+  saveGlobalConfig(current => ({ ...current, model: 'kimi-k2.6' }))
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_BASE_URL = 'https://chatgpt.com/backend-api/codex'
+  process.env.OPENAI_MODEL = 'codexplan'
+  process.env.CODEX_API_KEY = 'codex-test'
+  process.env.CHATGPT_ACCOUNT_ID = 'acct_test'
+
+  const model = getUserSpecifiedModelSetting()
+  expect(model).toBe('codexplan')
+})
+
+test('nvidia-nim provider reads OPENAI_MODEL, not stale settings.model', () => {
+  saveGlobalConfig(current => ({ ...current, model: 'kimi-k2.6' }))
+  process.env.NVIDIA_NIM = '1'
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_MODEL = 'nvidia/llama-3.1-nemotron-70b-instruct'
+
+  const model = getUserSpecifiedModelSetting()
+  expect(model).toBe('nvidia/llama-3.1-nemotron-70b-instruct')
+})
+
+test('minimax provider reads OPENAI_MODEL, not stale settings.model', () => {
+  saveGlobalConfig(current => ({ ...current, model: 'kimi-k2.6' }))
+  process.env.MINIMAX_API_KEY = 'minimax-test'
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_MODEL = 'MiniMax-M2.5'
+
+  const model = getUserSpecifiedModelSetting()
+  expect(model).toBe('MiniMax-M2.5')
+})
+
+test('openai provider still reads OPENAI_MODEL (regression guard)', () => {
+  saveGlobalConfig(current => ({ ...current, model: 'stale-default' }))
+  process.env.CLAUDE_CODE_USE_OPENAI = '1'
+  process.env.OPENAI_MODEL = 'gpt-4o'
+
+  const model = getUserSpecifiedModelSetting()
+  expect(model).toBe('gpt-4o')
+})
+
+test('github provider still reads OPENAI_MODEL (regression guard)', () => {
+  saveGlobalConfig(current => ({ ...current, model: 'stale-default' }))
+  process.env.CLAUDE_CODE_USE_GITHUB = '1'
+  process.env.OPENAI_MODEL = 'github:copilot'
+
+  const model = getUserSpecifiedModelSetting()
+  expect(model).toBe('github:copilot')
+})
+

src/utils/model/model.ts

@@ -91,11 +91,24 @@ export function getUserSpecifiedModelSetting(): ModelSetting | undefined {
     const setting = normalizeModelSetting(settings.model)
     // Read the model env var that matches the active provider to prevent
     // cross-provider leaks (e.g. ANTHROPIC_MODEL sent to the OpenAI API).
+    //
+    // All OpenAI-shim providers (openai, codex, github, nvidia-nim, minimax)
+    // set CLAUDE_CODE_USE_OPENAI=1 + OPENAI_MODEL via
+    // applyProviderProfileToProcessEnv. Earlier this check only included
+    // openai/github — codex/nvidia-nim/minimax fell through to the stale
+    // settings.model, so switching from (say) Moonshot to Codex kept firing
+    // `kimi-k2.6` at the Codex endpoint and getting 400s.
     const provider = getAPIProvider()
+    const isOpenAIShimProvider =
+      provider === 'openai' ||
+      provider === 'codex' ||
+      provider === 'github' ||
+      provider === 'nvidia-nim' ||
+      provider === 'minimax'
     specifiedModel =
       (provider === 'gemini' ? process.env.GEMINI_MODEL : undefined) ||
       (provider === 'mistral' ? process.env.MISTRAL_MODEL : undefined) ||
-      (provider === 'openai' || provider === 'gemini' || provider === 'mistral' || provider === 'github' ? process.env.OPENAI_MODEL : undefined) ||
+      (isOpenAIShimProvider ? process.env.OPENAI_MODEL : undefined) ||
       (provider === 'firstParty' ? process.env.ANTHROPIC_MODEL : undefined) ||
       setting ||
       undefined