diff --git a/.gitignore b/.gitignore
index 6f0a4e069..f2251f2c5 100644
--- a/.gitignore
+++ b/.gitignore
@@ -38,3 +38,7 @@ data
 .codex/skills/.system/**
 !.codex/prompts/
 !.codex/prompts/**
+
+.costrict
+.claude
+.tmp/
\ No newline at end of file
diff --git a/src/commands/provider.ts b/src/commands/provider.ts
index 19b19c021..e7b0ff101 100644
--- a/src/commands/provider.ts
+++ b/src/commands/provider.ts
@@ -4,6 +4,7 @@ import { getAPIProvider } from '../utils/model/providers.js'
 import { updateSettingsForSource } from '../utils/settings/settings.js'
 import { getSettings_DEPRECATED } from '../utils/settings/settings.js'
 import { applyConfigEnvironmentVariables } from '../utils/managedEnv.js'
+import { getDefaultSonnetModel, getDefaultOpusModel, getDefaultHaikuModel } from '../utils/model/model.js'
 
 function getEnvVarForProvider(provider: string): string {
   switch (provider) {
@@ -43,6 +44,28 @@ const call: LocalCommandCall = async (args, context) => {
     return { type: 'text', value: `Current API provider: ${current}` }
   }
 
+  // Helper function to set default model based on provider
+  const setDefaultModel = (provider: string) => {
+    const settings = getSettings_DEPRECATED() || {}
+    const currentModel = settings.model
+
+    // Only set default if no model has been explicitly set
+    if (!currentModel) {
+      let defaultModel: string
+      switch (provider) {
+        case 'anthropic':
+          defaultModel = getDefaultSonnetModel()
+          break
+        case 'openai':
+        case 'gemini':
+        case 'grok':
+        default:
+          defaultModel = getDefaultSonnetModel()
+      }
+      updateSettingsForSource('userSettings', { model: defaultModel })
+    }
+  }
+
   // unset - clear settings, fallback to env vars
   if (arg === 'unset') {
     updateSettingsForSource('userSettings', { modelType: undefined })
@@ -53,6 +76,7 @@ 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
+    delete process.env.CLAUDE_CODE_USE_COSTRICT
     return {
       type: 'text',
       value: 'API provider cleared (will use environment variables).',
@@ -83,6 +107,7 @@ const call: LocalCommandCall = async (args, context) => {
     const hasUrl = !!mergedEnv.OPENAI_BASE_URL
     if (!hasKey || !hasUrl) {
       updateSettingsForSource('userSettings', { modelType: 'openai' })
+      setDefaultModel('openai')
       const missing = []
       if (!hasKey) missing.push('OPENAI_API_KEY')
       if (!hasUrl) missing.push('OPENAI_BASE_URL')
@@ -99,6 +124,7 @@ const call: LocalCommandCall = async (args, context) => {
     const hasKey = !!(mergedEnv.GROK_API_KEY || mergedEnv.XAI_API_KEY)
     if (!hasKey) {
       updateSettingsForSource('userSettings', { modelType: 'grok' })
+      setDefaultModel('grok')
       return {
         type: 'text',
         value: `Switched to Grok provider.\nWarning: Missing env var: GROK_API_KEY (or XAI_API_KEY)\nConfigure it via settings.json env or set manually.`,
@@ -113,6 +139,7 @@ const call: LocalCommandCall = async (args, context) => {
     // GEMINI_BASE_URL is optional (has default)
     if (!hasKey) {
       updateSettingsForSource('userSettings', { modelType: 'gemini' })
+      setDefaultModel('gemini')
       return {
         type: 'text',
         value: `Switched to Gemini provider.\nWarning: Missing env var: GEMINI_API_KEY\nConfigure it via /login or set manually.`,
@@ -131,8 +158,11 @@ 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
+    delete process.env.CLAUDE_CODE_USE_COSTRICT
     // Update settings.json
     updateSettingsForSource('userSettings', { modelType: arg })
+    // Set default model for the provider
+    setDefaultModel(arg)
     // Ensure settings.env gets applied to process.env
     applyConfigEnvironmentVariables()
     return { type: 'text', value: `API provider set to ${arg}.` }
diff --git a/src/components/ConsoleOAuthFlow.tsx b/src/components/ConsoleOAuthFlow.tsx
index 7b973fe75..0f6acd502 100644
--- a/src/components/ConsoleOAuthFlow.tsx
+++ b/src/components/ConsoleOAuthFlow.tsx
@@ -13,9 +13,11 @@ import { OAuthService } from '../services/oauth/index.js'
 import { getOauthAccountInfo, validateForceLoginOrg } from '../utils/auth.js'
 import { logError } from '../utils/log.js'
 import { getSettings_DEPRECATED, updateSettingsForSource } from '../utils/settings/settings.js'
+import { getDefaultSonnetModel } from '../utils/model/model.js'
 import { Select } from './CustomSelect/select.js'
 import { Spinner } from './Spinner.js'
 import TextInput from './TextInput.js'
+import { useSetAppState } from '../state/AppState.js'
 import { fi } from 'zod/v4/locales'
 
 type Props = {
@@ -28,6 +30,14 @@ type Props = {
 type OAuthStatus =
   | { state: 'idle' } // Initial state, waiting to select login method
   | { state: 'platform_setup' } // Show platform setup info (Bedrock/Vertex/Foundry)
+  | {
+      state: 'costrict_waiting'
+      url: string
+    } // CoStrict OAuth: browser opened, waiting for user to login
+  | {
+      state: 'costrict_model_select'
+      models: Array<{ id: string; name?: string }>
+    } // CoStrict: login done, select a model
   | {
       state: 'custom_platform'
       baseUrl: string
@@ -94,6 +104,7 @@ export function ConsoleOAuthFlow({
     }
     return { state: 'idle' }
   })
+  const setAppState = useSetAppState()
 
   const [pastedCode, setPastedCode] = useState('')
   const [cursorOffset, setCursorOffset] = useState(0)
@@ -273,6 +284,10 @@ export function ConsoleOAuthFlow({
         }
         // Reset modelType to anthropic when using OAuth login
         updateSettingsForSource('userSettings', { modelType: 'anthropic' } as any)
+        // Set default model to sonnet for Anthropic provider
+        updateSettingsForSource('userSettings', { model: getDefaultSonnetModel() } as any)
+        // Clear costrict env var to prevent conflicts
+        delete process.env.CLAUDE_CODE_USE_COSTRICT
 
         setOAuthStatus({ state: 'success' })
         void sendNotification(
@@ -438,6 +453,7 @@ function OAuthStatusMessage({
   setLoginWithClaudeAi,
   onDone,
 }: OAuthStatusMessageProps): React.ReactNode {
+  const setAppState = useSetAppState()
   switch (oauthStatus.state) {
     case 'idle':
       return (
@@ -453,6 +469,16 @@ function OAuthStatusMessage({
           <Box>
             <Select
               options={[
+                {
+                  label: (
+                    <Text>
+                      CoStrict ·{' '}
+                      <Text dimColor>Sign in with CoStrict account</Text>
+                      {'\n'}
+                    </Text>
+                  ),
+                  value: 'costrict',
+                },
                 {
                   label: (
                     <Text>
@@ -485,52 +511,72 @@ function OAuthStatusMessage({
                   ),
                   value: 'gemini_api',
                 },
-                {
-                  label: (
-                    <Text>
-                      Claude account with subscription ·{' '}
-                      <Text dimColor>Pro, Max, Team, or Enterprise</Text>
-                      {process.env.USER_TYPE === 'ant' && (
-                        <Text>
-                          {'\n'}
-                          <Text color="warning">[ANT-ONLY]</Text>{' '}
-                          <Text dimColor>
-                            Please use this option unless you need to login to a
-                            special org for accessing sensitive data (e.g.
-                            customer data, HIPI data) with the Console option
-                          </Text>
-                        </Text>
-                      )}
-                      {'\n'}
-                    </Text>
-                  ),
-                  value: 'claudeai',
-                },
-                {
-                  label: (
-                    <Text>
-                      Anthropic Console account ·{' '}
-                      <Text dimColor>API usage billing</Text>
-                      {'\n'}
-                    </Text>
-                  ),
-                  value: 'console',
-                },
-                {
-                  label: (
-                    <Text>
-                      3rd-party platform ·{' '}
-                      <Text dimColor>
-                        Amazon Bedrock, Microsoft Foundry, or Vertex AI
-                      </Text>
-                      {'\n'}
-                    </Text>
-                  ),
-                  value: 'platform',
-                },
               ]}
               onChange={value => {
-                if (value === 'custom_platform') {
+                if (value === 'costrict') {
+                  void (async () => {
+                    try {
+                      const { generateState, getCoStrictBaseURL, buildCoStrictLoginURL, pollLoginToken } = await import('../costrict/provider/auth.js')
+                      const { generateMachineId, saveCoStrictCredentials } = await import('../costrict/provider/credentials.js')
+                      const { extractExpiryFromJWT } = await import('../costrict/provider/token.js')
+                      const { updateSettingsForSource } = await import('../utils/settings/settings.js')
+
+                      const baseUrl = getCoStrictBaseURL()
+                      const state = generateState()
+                      const machineId = generateMachineId()
+                      const loginUrl = buildCoStrictLoginURL(baseUrl, state, machineId)
+
+                      // 打开浏览器
+                      const { openBrowser } = await import('../utils/browser.js')
+                      await openBrowser(loginUrl)
+
+                      setOAuthStatus({ state: 'costrict_waiting', url: loginUrl })
+
+                      // 轮询等待登录完成
+                      const tokens = await pollLoginToken(baseUrl, state, machineId)
+
+                      // 保存凭证
+                      const expiryDate = extractExpiryFromJWT(tokens.access_token)
+                      await saveCoStrictCredentials({
+                        id: 'csc',
+                        name: 'CSC Auth',
+                        access_token: tokens.access_token,
+                        refresh_token: tokens.refresh_token,
+                        state,
+                        machine_id: machineId,
+                        base_url: baseUrl,
+                        expiry_date: expiryDate,
+                        updated_at: new Date().toISOString(),
+                        expired_at: expiryDate ? new Date(expiryDate).toISOString() : undefined,
+                      })
+
+                      // 设置 modelType 为 costrict
+                      updateSettingsForSource('userSettings', { modelType: 'costrict' as any } as any)
+                      process.env.CLAUDE_CODE_USE_COSTRICT = '1'
+
+                      // 预取模型列表，填充同步缓存，并进入模型选择界面
+                      try {
+                        const { fetchCoStrictModels } = await import('../costrict/provider/models.js')
+                        const models = await fetchCoStrictModels(baseUrl, tokens.access_token)
+                        if (models.length > 0) {
+                          setOAuthStatus({ state: 'costrict_model_select', models })
+                          return
+                        }
+                      } catch {
+                        // 预取失败，直接进入 success
+                      }
+
+                      setOAuthStatus({ state: 'success' })
+                      void onDone()
+                    } catch (err: any) {
+                      setOAuthStatus({
+                        state: 'error',
+                        message: err.message || String(err),
+                        toRetry: { state: 'idle' },
+                      })
+                    }
+                  })()
+                } else if (value === 'custom_platform') {
                   logEvent('tengu_custom_platform_selected', {})
                   setOAuthStatus({
                     state: 'custom_platform',
@@ -562,19 +608,7 @@ function OAuthStatusMessage({
                     sonnetModel: process.env.GEMINI_DEFAULT_SONNET_MODEL ?? '',
                     opusModel: process.env.GEMINI_DEFAULT_OPUS_MODEL ?? '',
                     activeField: 'base_url',
-                  })
-                } else if (value === 'platform') {
-                  logEvent('tengu_oauth_platform_selected', {})
-                  setOAuthStatus({ state: 'platform_setup' })
-                } else {
-                  setOAuthStatus({ state: 'ready_to_start' })
-                  if (value === 'claudeai') {
-                    logEvent('tengu_oauth_claudeai_selected', {})
-                    setLoginWithClaudeAi(true)
-                  } else {
-                    logEvent('tengu_oauth_console_selected', {})
-                    setLoginWithClaudeAi(false)
-                  }
+                  });
                 }
               }}
             />
@@ -696,6 +730,10 @@ function OAuthStatusMessage({
             })
           } else {
             for (const [k, v] of Object.entries(env)) process.env[k] = v
+            // Clear costrict env var to prevent conflicts when using custom platform
+            delete process.env.CLAUDE_CODE_USE_COSTRICT
+            // Set default model to sonnet for this provider
+            updateSettingsForSource('userSettings', { model: getDefaultSonnetModel() } as any)
             setOAuthStatus({ state: 'success' })
             void onDone()
           }
@@ -916,6 +954,10 @@ function OAuthStatusMessage({
             })
           } else {
             for (const [k, v] of Object.entries(env)) process.env[k] = v
+            // Clear costrict env var to prevent conflicts when using OpenAI
+            delete process.env.CLAUDE_CODE_USE_COSTRICT
+            // Set default model to sonnet for this provider
+            updateSettingsForSource('userSettings', { model: getDefaultSonnetModel() } as any)
             setOAuthStatus({ state: 'success' })
             void onDone()
           }
@@ -1149,6 +1191,10 @@ function OAuthStatusMessage({
             })
           } else {
             for (const [k, v] of Object.entries(env)) process.env[k] = v
+            // Clear costrict env var to prevent conflicts when using Gemini
+            delete process.env.CLAUDE_CODE_USE_COSTRICT
+            // Set default model to sonnet for this provider
+            updateSettingsForSource('userSettings', { model: getDefaultSonnetModel() } as any)
             setOAuthStatus({ state: 'success' })
             void onDone()
           }
@@ -1275,6 +1321,62 @@ function OAuthStatusMessage({
         )
       }
 
+    case 'costrict_waiting':
+      return (
+        <Box flexDirection="column" gap={1}>
+          <Text>
+            Opening browser for CoStrict login. If it does not open
+            automatically, copy and paste this URL:
+          </Text>
+          <Box marginY={1}>
+            <Text color="suggestion">{oauthStatus.url}</Text>
+          </Box>
+          <Text dimColor>Waiting for authentication...</Text>
+        </Box>
+      )
+
+    case 'costrict_model_select': {
+      const sortedModels = [...oauthStatus.models].sort((a, b) => a.id.localeCompare(b.id));
+      // 直接使用已获取的模型列表渲染选项，避免通用 ModelPicker 因 getAPIProvider() 竞态
+      // 导致显示标准 Anthropic 模型列表而非 CoStrict 动态模型
+      const costrictOptions = sortedModels.map(m => ({
+        value: m.id,
+        label: m.name ?? m.id,
+        description:
+          m.id === 'Auto'
+            ? `${Math.round(((m as any).creditDiscount ?? 0) * 100)}% discount`
+            : `${(m as any).creditConsumption ?? '?'}x credit`,
+      }));
+      return (
+        <Box flexDirection="column">
+          <Box marginBottom={1} flexDirection="column">
+            <Text color="remember" bold>
+              Select model
+            </Text>
+            <Text dimColor>Login successful. Select a CoStrict model to use:</Text>
+          </Box>
+          <Box flexDirection="column" marginBottom={1}>
+            <Select
+              options={costrictOptions}
+              onChange={(value: string) => {
+                process.env.COSTRICT_MODEL = value;
+                setAppState(prev => ({ ...prev, mainLoopModel: value, mainLoopModelForSession: null }));
+                setOAuthStatus({ state: 'success' });
+                void onDone();
+              }}
+              onCancel={() => {
+                const selected = sortedModels[0]?.id ?? '';
+                process.env.COSTRICT_MODEL = selected;
+                setAppState(prev => ({ ...prev, mainLoopModel: selected, mainLoopModelForSession: null }));
+                setOAuthStatus({ state: 'success' });
+                void onDone();
+              }}
+            />
+          </Box>
+        </Box>
+      );
+    }
+
     case 'platform_setup':
       return (
         <Box flexDirection="column" gap={1} marginTop={1}>
diff --git a/src/costrict/provider/fetch.ts b/src/costrict/provider/fetch.ts
index dabbf532a..14dbefc92 100644
--- a/src/costrict/provider/fetch.ts
+++ b/src/costrict/provider/fetch.ts
@@ -34,6 +34,10 @@ function getVersion(): string {
 
 const VERSION = getVersion()
 
+type CoStrictFetch = typeof fetch & {
+  preconnect?: (url: string | URL) => void
+}
+
 /**
  * 创建自定义 fetch 函数，用于 CoStrict API 请求
  *
@@ -43,7 +47,7 @@ const VERSION = getVersion()
  * 3. 注入 Authorization 和 CoStrict 特有 headers
  * 4. 反应性 401 错误恢复（自动重试一次）
  */
-export function createCoStrictFetch() {
+export function createCoStrictFetch(): CoStrictFetch {
   const costrictFetch = async (
     input: RequestInfo | URL,
     init?: RequestInit,
@@ -126,20 +130,21 @@ export function createCoStrictFetch() {
   }
   // Bun 原生支持 fetch.preconnect（共享连接池预热）
   // Node.js 没有 preconnect API，降级为 net.createConnection 做 TCP 预热
-  if (typeof fetch.preconnect === 'function') {
-    costrictFetch.preconnect = fetch.preconnect.bind(fetch)
-  } else {
-    costrictFetch.preconnect = (url: string | URL) => {
-      try {
-        const { hostname, port } = new URL(typeof url === 'string' ? url : url.toString())
-        const { createConnection } = require('node:net') as typeof import('node:net')
-        const sock = createConnection(Number(port) || 443, hostname, () => sock.destroy())
-        sock.setTimeout(3000, () => sock.destroy())
-        sock.on('error', () => sock.destroy())
-      } catch {
-        // 预连接失败不影响正常流程
-      }
-    }
-  }
-  return costrictFetch
+  const costrictFetchWithPreconnect = Object.assign(costrictFetch, {
+    preconnect: typeof fetch.preconnect === 'function'
+      ? fetch.preconnect.bind(fetch)
+      : (url: string | URL) => {
+          try {
+            const { hostname, port } = new URL(typeof url === 'string' ? url : url.toString())
+            const { createConnection } = require('node:net') as typeof import('node:net')
+            const sock = createConnection(Number(port) || 443, hostname, () => sock.destroy())
+            sock.setTimeout(3000, () => sock.destroy())
+            sock.on('error', () => sock.destroy())
+          } catch {
+            // 预连接失败不影响正常流程
+          }
+        }
+  })
+
+  return costrictFetchWithPreconnect as CoStrictFetch
 }
diff --git a/src/costrict/provider/index.ts b/src/costrict/provider/index.ts
index b8c72df4a..fc2f916ee 100644
--- a/src/costrict/provider/index.ts
+++ b/src/costrict/provider/index.ts
@@ -16,12 +16,7 @@ import type { Tools } from '../../Tool.js'
 import type { Options } from '../../services/api/claude.js'
 import OpenAI from 'openai'
 import { getProxyFetchOptions } from '../../utils/proxy.js'
-import { anthropicMessagesToOpenAI } from '../../services/api/openai/convertMessages.js'
-import {
-  anthropicToolsToOpenAI,
-  anthropicToolChoiceToOpenAI,
-} from '../../services/api/openai/convertTools.js'
-import { adaptOpenAIStreamToAnthropic } from '../../services/api/openai/streamAdapter.js'
+import { anthropicMessagesToOpenAI, anthropicToolsToOpenAI, anthropicToolChoiceToOpenAI, adaptOpenAIStreamToAnthropic } from '@ant/model-provider'
 import { normalizeMessagesForAPI } from '../../utils/messages.js'
 import { toolToAPISchema } from '../../utils/api.js'
 import { logForDebugging } from '../../utils/debug.js'
diff --git a/src/utils/model/modelOptions.ts b/src/utils/model/modelOptions.ts
index 16798ef84..55a5c2fde 100644
--- a/src/utils/model/modelOptions.ts
+++ b/src/utils/model/modelOptions.ts
@@ -33,7 +33,6 @@ import {
 } from './model.js'
 import { has1mContext } from '../context.js'
 import { getGlobalConfig } from '../config.js'
-import { hasCoStrictCredentialsSync } from '../../costrict/provider/credentials.js'
 
 // @[MODEL LAUNCH]: Update all the available and default model option strings below.
 
@@ -380,10 +379,8 @@ function getModelOptionsBase(fastMode = false): ModelOption[] {
   }
 
   // CoStrict provider: 从缓存中动态展示 CoStrict 可用模型
-  // 也覆盖其他 provider 但用户已有 CoStrict 凭证的场景（modelType 丢失/竞态）
   const isCoStrictProvider = getAPIProvider() === 'costrict'
-  const hasCoStrictCreds = hasCoStrictCredentialsSync()
-  if (isCoStrictProvider || hasCoStrictCreds) {
+  if (isCoStrictProvider) {
     // 延迟 require 避免循环依赖，且该模块只在 costrict provider 下加载
     // eslint-disable-next-line @typescript-eslint/no-require-imports
     const { getCachedCoStrictModels } =
@@ -414,21 +411,27 @@ function getModelOptionsBase(fastMode = false): ModelOption[] {
     ]
   }
 
-  // 用户没有 CoStrict 凭证，显示推荐登录选项
-  return [getCoStrictLoginOption()]
-}
-
-/**
- * CoStrict 登录推荐选项
- * 当用户未登录 CoStrict 时显示，提示用户可以登录以使用 CoStrict 模型
- */
-function getCoStrictLoginOption(): ModelOption {
-  return {
-    value: 'costrict-login',
-    label: 'CoStrict (Recommended)',
-    description:
-      'Sign in to CoStrict for more models and better pricing · Run /login and select CoStrict',
+  // PAYG 用户：展示标准模型选项（Sonnet, Opus, Haiku 等）
+  const paygOptions = [getDefaultOptionForUser(fastMode)]
+  const customSonnet = getCustomSonnetOption()
+  if (customSonnet) {
+    paygOptions.push(customSonnet)
+  } else {
+    paygOptions.push(getSonnet46Option())
   }
+  const customOpus = getCustomOpusOption()
+  if (customOpus) {
+    paygOptions.push(customOpus)
+  } else {
+    paygOptions.push(getOpus46Option(fastMode))
+  }
+  const customHaiku = getCustomHaikuOption()
+  if (customHaiku) {
+    paygOptions.push(customHaiku)
+  } else {
+    paygOptions.push(getHaikuOption())
+  }
+  return paygOptions
 }
 
 // @[MODEL LAUNCH]: Add the new model ID to the appropriate family pattern below
@@ -549,11 +552,6 @@ export function getModelOptions(fastMode = false): ModelOption[] {
   } else if (initialMainLoopModel !== null) {
     customModel = initialMainLoopModel
   }
-  // 忽略 costrict-login 伪模型值（用户点击了推荐登录选项但未完成登录）
-  if (customModel === 'costrict-login') {
-    return filterModelOptionsByAllowlist(options)
-  }
-
   if (customModel === null || options.some(opt => opt.value === customModel)) {
     return filterModelOptionsByAllowlist(options)
   } else if (customModel === 'opusplan') {