diff --git a/build.ts b/build.ts
index 857aefe8e..6fe75cc4c 100644
--- a/build.ts
+++ b/build.ts
@@ -59,6 +59,7 @@ const result = await Bun.build({
   splitting: true,
   define: getMacroDefines(),
   features,
+  external: ['openai'],
 })
 
 if (!result.success) {
diff --git a/src/commands/login/login.tsx b/src/commands/login/login.tsx
index b4329fe62..ea01527ba 100644
--- a/src/commands/login/login.tsx
+++ b/src/commands/login/login.tsx
@@ -22,6 +22,9 @@ import {
   resetAutoModeGateCheck,
   resetBypassPermissionsCheck,
 } from '../../utils/permissions/bypassPermissionsKillswitch.js'
+import { applyConfigEnvironmentVariables } from '../../utils/managedEnv.js'
+import { resetModelStrings } from '../../utils/model/modelStrings.js'
+import { resetSettingsCache } from '../../utils/settings/settingsCache.js'
 import { resetUserCache } from '../../utils/user.js'
 
 export async function call(
@@ -40,6 +43,9 @@ export async function call(
           // Reset cost state when switching accounts
           resetCostState()
           // Refresh remotely managed settings after login (non-blocking)
+          resetSettingsCache()
+          applyConfigEnvironmentVariables()
+          resetModelStrings()
           void refreshRemoteManagedSettings()
           // Refresh policy limits after login (non-blocking)
           void refreshPolicyLimits()
diff --git a/src/services/api/grok/client.ts b/src/services/api/grok/client.ts
index 060d12636..87bb4f4f2 100644
--- a/src/services/api/grok/client.ts
+++ b/src/services/api/grok/client.ts
@@ -1,4 +1,4 @@
-import OpenAI from 'openai'
+import type OpenAI from 'openai'
 import { getProxyFetchOptions } from 'src/utils/proxy.js'
 
 /**
@@ -12,17 +12,18 @@ const DEFAULT_BASE_URL = 'https://api.x.ai/v1'
 
 let cachedClient: OpenAI | null = null
 
-export function getGrokClient(options?: {
+export async function getGrokClient(options?: {
   maxRetries?: number
   fetchOverride?: typeof fetch
   source?: string
-}): OpenAI {
+}): Promise<OpenAI> {
   if (cachedClient) return cachedClient
 
+  const { default: OpenAIClass } = await import('openai')
   const apiKey = process.env.GROK_API_KEY || process.env.XAI_API_KEY || ''
   const baseURL = process.env.GROK_BASE_URL || DEFAULT_BASE_URL
 
-  const client = new OpenAI({
+  const client = new OpenAIClass({
     apiKey,
     baseURL,
     maxRetries: options?.maxRetries ?? 0,
diff --git a/src/services/api/grok/index.ts b/src/services/api/grok/index.ts
index 3198e85f6..536ec7b0b 100644
--- a/src/services/api/grok/index.ts
+++ b/src/services/api/grok/index.ts
@@ -65,7 +65,7 @@ export async function* queryModelGrok(
     const openaiTools = anthropicToolsToOpenAI(standardTools)
     const openaiToolChoice = anthropicToolChoiceToOpenAI(options.toolChoice)
 
-    const client = getGrokClient({
+    const client = await getGrokClient({
       maxRetries: 0,
       fetchOverride: options.fetchOverride as typeof fetch | undefined,
       source: options.querySource,
@@ -187,7 +187,8 @@ export async function* queryModelGrok(
     }
   } catch (error) {
     const errorMessage = error instanceof Error ? error.message : String(error)
-    logForDebugging(`[Grok] Error: ${errorMessage}`, { level: 'error' })
+    const stack = error instanceof Error ? `\n${error.stack}` : ''
+    logForDebugging(`[Grok] Error: ${errorMessage}${stack}`, { level: 'error' })
     yield createAssistantAPIErrorMessage({
       content: `API Error: ${errorMessage}`,
       apiError: 'api_error',
diff --git a/src/services/api/grok/modelMapping.ts b/src/services/api/grok/modelMapping.ts
index f3e40edbc..2a62f5ef6 100644
--- a/src/services/api/grok/modelMapping.ts
+++ b/src/services/api/grok/modelMapping.ts
@@ -5,27 +5,31 @@
  * or override the entire mapping via GROK_MODEL_MAP env var (JSON string):
  *   GROK_MODEL_MAP='{"opus":"grok-4","sonnet":"grok-3","haiku":"grok-3-mini-fast"}'
  */
-const DEFAULT_MODEL_MAP: Record<string, string> = {
-  'claude-sonnet-4-20250514': 'grok-3-mini-fast',
-  'claude-sonnet-4-5-20250929': 'grok-3-mini-fast',
-  'claude-sonnet-4-6': 'grok-3-mini-fast',
-  'claude-opus-4-20250514': 'grok-4.20-reasoning',
-  'claude-opus-4-1-20250805': 'grok-4.20-reasoning',
-  'claude-opus-4-5-20251101': 'grok-4.20-reasoning',
-  'claude-opus-4-6': 'grok-4.20-reasoning',
-  'claude-haiku-4-5-20251001': 'grok-3-mini-fast',
-  'claude-3-5-haiku-20241022': 'grok-3-mini-fast',
-  'claude-3-7-sonnet-20250219': 'grok-3-mini-fast',
-  'claude-3-5-sonnet-20241022': 'grok-3-mini-fast',
+function getDefaultModelMap(): Record<string, string> {
+  return {
+    'claude-sonnet-4-20250514': 'grok-3-mini-fast',
+    'claude-sonnet-4-5-20250929': 'grok-3-mini-fast',
+    'claude-sonnet-4-6': 'grok-3-mini-fast',
+    'claude-opus-4-20250514': 'grok-4.20-reasoning',
+    'claude-opus-4-1-20250805': 'grok-4.20-reasoning',
+    'claude-opus-4-5-20251101': 'grok-4.20-reasoning',
+    'claude-opus-4-6': 'grok-4.20-reasoning',
+    'claude-haiku-4-5-20251001': 'grok-3-mini-fast',
+    'claude-3-5-haiku-20241022': 'grok-3-mini-fast',
+    'claude-3-7-sonnet-20250219': 'grok-3-mini-fast',
+    'claude-3-5-sonnet-20241022': 'grok-3-mini-fast',
+  }
 }
 
 /**
  * Family-level mapping defaults (used by GROK_MODEL_MAP).
  */
-const DEFAULT_FAMILY_MAP: Record<string, string> = {
-  opus: 'grok-4.20-reasoning',
-  sonnet: 'grok-3-mini-fast',
-  haiku: 'grok-3-mini-fast',
+function getDefaultFamilyMap(): Record<string, string> {
+  return {
+    opus: 'grok-4.20-reasoning',
+    sonnet: 'grok-3-mini-fast',
+    haiku: 'grok-3-mini-fast',
+  }
 }
 
 function getModelFamily(model: string): 'haiku' | 'sonnet' | 'opus' | null {
@@ -93,13 +97,13 @@ export function resolveGrokModel(anthropicModel: string): string {
   }
 
   // 5. Exact model name lookup
-  if (DEFAULT_MODEL_MAP[cleanModel]) {
-    return DEFAULT_MODEL_MAP[cleanModel]
+  if (getDefaultModelMap()[cleanModel]) {
+    return getDefaultModelMap()[cleanModel]
   }
 
   // 6. Family-level default
-  if (family && DEFAULT_FAMILY_MAP[family]) {
-    return DEFAULT_FAMILY_MAP[family]
+  if (family && getDefaultFamilyMap()[family]) {
+    return getDefaultFamilyMap()[family]
   }
 
   // 7. Pass through
diff --git a/src/services/api/openai/client.ts b/src/services/api/openai/client.ts
index 62a37dfbc..adaae3116 100644
--- a/src/services/api/openai/client.ts
+++ b/src/services/api/openai/client.ts
@@ -1,4 +1,4 @@
-import OpenAI from 'openai'
+import type OpenAI from 'openai'
 import { getProxyFetchOptions } from 'src/utils/proxy.js'
 import { isEnvTruthy } from 'src/utils/envUtils.js'
 
@@ -13,17 +13,18 @@ import { isEnvTruthy } from 'src/utils/envUtils.js'
 
 let cachedClient: OpenAI | null = null
 
-export function getOpenAIClient(options?: {
+export async function getOpenAIClient(options?: {
   maxRetries?: number
   fetchOverride?: typeof fetch
   source?: string
-}): OpenAI {
+}): Promise<OpenAI> {
   if (cachedClient) return cachedClient
 
+  const { default: OpenAIClass } = await import('openai')
   const apiKey = process.env.OPENAI_API_KEY || ''
   const baseURL = process.env.OPENAI_BASE_URL
 
-  const client = new OpenAI({
+  const client = new OpenAIClass({
     apiKey,
     ...(baseURL && { baseURL }),
     maxRetries: options?.maxRetries ?? 0,
diff --git a/src/services/api/openai/index.ts b/src/services/api/openai/index.ts
index 040907006..7cc69ba23 100644
--- a/src/services/api/openai/index.ts
+++ b/src/services/api/openai/index.ts
@@ -290,7 +290,7 @@ export async function* queryModelOpenAI(
     const maxTokens = options.maxOutputTokensOverride ?? upperLimit
 
     // 11. Get client
-    const client = getOpenAIClient({
+    const client = await getOpenAIClient({
       maxRetries: 0,
       fetchOverride: options.fetchOverride as unknown as typeof fetch,
       source: options.querySource,
@@ -432,7 +432,8 @@ export async function* queryModelOpenAI(
     }
   } catch (error) {
     const errorMessage = error instanceof Error ? error.message : String(error)
-    logForDebugging(`[OpenAI] Error: ${errorMessage}`, { level: 'error' })
+    const stack = error instanceof Error ? `\n${error.stack}` : ''
+    logForDebugging(`[OpenAI] Error: ${errorMessage}${stack}`, { level: 'error' })
     yield createAssistantAPIErrorMessage({
       content: `API Error: ${errorMessage}`,
       apiError: 'api_error',
diff --git a/src/services/api/openai/modelMapping.ts b/src/services/api/openai/modelMapping.ts
index 7cb49c7f9..2b88774fa 100644
--- a/src/services/api/openai/modelMapping.ts
+++ b/src/services/api/openai/modelMapping.ts
@@ -2,18 +2,20 @@
  * Default mapping from Anthropic model names to OpenAI model names.
  * Used only when ANTHROPIC_DEFAULT_*_MODEL env vars are not set.
  */
-const DEFAULT_MODEL_MAP: Record<string, string> = {
-  'claude-sonnet-4-20250514': 'gpt-4o',
-  'claude-sonnet-4-5-20250929': 'gpt-4o',
-  'claude-sonnet-4-6': 'gpt-4o',
-  'claude-opus-4-20250514': 'o3',
-  'claude-opus-4-1-20250805': 'o3',
-  'claude-opus-4-5-20251101': 'o3',
-  'claude-opus-4-6': 'o3',
-  'claude-haiku-4-5-20251001': 'gpt-4o-mini',
-  'claude-3-5-haiku-20241022': 'gpt-4o-mini',
-  'claude-3-7-sonnet-20250219': 'gpt-4o',
-  'claude-3-5-sonnet-20241022': 'gpt-4o',
+function getDefaultModelMap(): Record<string, string> {
+  return {
+    'claude-sonnet-4-20250514': 'gpt-4o',
+    'claude-sonnet-4-5-20250929': 'gpt-4o',
+    'claude-sonnet-4-6': 'gpt-4o',
+    'claude-opus-4-20250514': 'o3',
+    'claude-opus-4-1-20250805': 'o3',
+    'claude-opus-4-5-20251101': 'o3',
+    'claude-opus-4-6': 'o3',
+    'claude-haiku-4-5-20251001': 'gpt-4o-mini',
+    'claude-3-5-haiku-20241022': 'gpt-4o-mini',
+    'claude-3-7-sonnet-20250219': 'gpt-4o',
+    'claude-3-5-sonnet-20241022': 'gpt-4o',
+  }
 }
 
 /**
@@ -59,5 +61,5 @@ export function resolveOpenAIModel(anthropicModel: string): string {
     if (anthropicOverride) return anthropicOverride
   }
 
-  return DEFAULT_MODEL_MAP[cleanModel] ?? cleanModel
+  return getDefaultModelMap()?.[cleanModel] ?? cleanModel
 }
diff --git a/src/utils/model/modelStrings.ts b/src/utils/model/modelStrings.ts
index 5b7be104f..4b1d97330 100644
--- a/src/utils/model/modelStrings.ts
+++ b/src/utils/model/modelStrings.ts
@@ -143,7 +143,13 @@ export function getModelStrings(): ModelStrings {
   }
   return applyModelOverrides(ms)
 }
-
+/**
+ * Reset the modelStrings cache so it re-initializes with the current provider on next access.
+ * Call this after switching providers (e.g. after /login).
+ */
+export function resetModelStrings(): void {
+  setModelStringsState(null as unknown as ModelStrings)
+}
 /**
  * Ensure model strings are fully initialized.
  * For Bedrock users, this waits for the profile fetch to complete.