diff --git a/src/costrict/provider/modelMapping.ts b/src/costrict/provider/modelMapping.ts
index 73a415f3d..ac8ecae7c 100644
--- a/src/costrict/provider/modelMapping.ts
+++ b/src/costrict/provider/modelMapping.ts
@@ -17,10 +17,9 @@ function getModelFamily(model: string): 'haiku' | 'sonnet' | 'opus' | null {
  *
  * 优先级:
  * 1. 传入的 model 本身就是已知的 CoStrict 模型 ID（用户通过 /model 明确选择）
- * 2. COSTRICT_MODEL 环境变量（管理员全局覆盖 / 登录默认值）
- * 3. COSTRICT_DEFAULT_{FAMILY}_MODEL 环境变量（按模型族）
- * 4. 已缓存的 CoStrict 模型列表中的第一个
- * 5. 直接透传原始模型名（最后兜底）
+ * 2. COSTRICT_DEFAULT_{FAMILY}_MODEL 环境变量（按模型族）
+ * 3. 直接透传原始模型名（用户手动配置的模型名）
+ * 4. COSTRICT_MODEL 环境变量（仅作为最终兜底）
  */
 export function resolveCoStrictModel(anthropicModel: string): string {
   const cleanModel = anthropicModel.replace(/\[1m\]$/, '')
@@ -29,10 +28,7 @@ export function resolveCoStrictModel(anthropicModel: string): string {
   const cached = getCachedCoStrictModels()
   if (cached.some(m => m.id === cleanModel)) return cleanModel
 
-  // 优先级 2: COSTRICT_MODEL 环境变量
-  if (process.env.COSTRICT_MODEL) return process.env.COSTRICT_MODEL
-
-  // 优先级 3: COSTRICT_DEFAULT_{FAMILY}_MODEL 环境变量
+  // 优先级 2: COSTRICT_DEFAULT_{FAMILY}_MODEL 环境变量
   const family = getModelFamily(cleanModel)
   if (family) {
     const envVar = `COSTRICT_DEFAULT_${family.toUpperCase()}_MODEL`
@@ -40,9 +36,6 @@ export function resolveCoStrictModel(anthropicModel: string): string {
     if (override) return override
   }
 
-  // 优先级 4: 缓存中的第一个模型
-  if (cached.length > 0) return cached[0].id
-
-  // 优先级 5: 透传原始模型名
+  // 优先级 3: 直接透传原始模型名（用户手动配置的模型名优先于环境变量）
   return cleanModel
 }
diff --git a/src/setup.ts b/src/setup.ts
index d2bb9451d..eca42d030 100644
--- a/src/setup.ts
+++ b/src/setup.ts
@@ -433,9 +433,8 @@ export async function setup(
         // 预取模型列表，填充同步缓存
         const baseUrl = getCoStrictBaseURL(activeCreds.base_url)
         const models = await fetchCoStrictModels(baseUrl, activeCreds.access_token)
-        if (models.length > 0 && !process.env.COSTRICT_MODEL) {
-          process.env.COSTRICT_MODEL = models[0].id
-        }
+        // 模型列表已预取并缓存，不再自动设置 COSTRICT_MODEL 环境变量
+        // resolveCoStrictModel() 会直接透传用户配置的模型名
         process.env.CLAUDE_CODE_USE_COSTRICT = '1'
       } catch {
         // 初始化失败不阻断启动
diff --git a/src/utils/model/model.ts b/src/utils/model/model.ts
index 61cccbcf9..21a8f7c49 100644
--- a/src/utils/model/model.ts
+++ b/src/utils/model/model.ts
@@ -36,6 +36,8 @@ export type ModelSetting = ModelName | ModelAlias | null
 
 export function getSmallFastModel(): ModelName {
   const provider = getAPIProvider()
+  // CoStrict has no haiku alias — use the main loop model to stay on the same provider
+  if (provider === 'costrict') return getMainLoopModel()
   // Provider-specific small fast model
   if (provider === 'openai' && process.env.OPENAI_SMALL_FAST_MODEL) {
     return process.env.OPENAI_SMALL_FAST_MODEL
@@ -149,6 +151,8 @@ export function getDefaultOpusModel(): ModelName {
 // @[MODEL LAUNCH]: Update the default Sonnet model (3P providers may lag so keep defaults unchanged).
 export function getDefaultSonnetModel(): ModelName {
   const provider = getAPIProvider()
+  // CoStrict has no sonnet alias — use the main loop model to stay on the same provider
+  if (provider === 'costrict') return getMainLoopModel()
   // For OpenAI provider, check OPENAI_DEFAULT_SONNET_MODEL first
   if (provider === 'openai' && process.env.OPENAI_DEFAULT_SONNET_MODEL) {
     return process.env.OPENAI_DEFAULT_SONNET_MODEL
@@ -171,6 +175,8 @@ export function getDefaultSonnetModel(): ModelName {
 // @[MODEL LAUNCH]: Update the default Haiku model (3P providers may lag so keep defaults unchanged).
 export function getDefaultHaikuModel(): ModelName {
   const provider = getAPIProvider()
+  // CoStrict has no haiku alias — use the main loop model to stay on the same provider
+  if (provider === 'costrict') return getMainLoopModel()
   // For OpenAI provider, check OPENAI_DEFAULT_HAIKU_MODEL first
   if (provider === 'openai' && process.env.OPENAI_DEFAULT_HAIKU_MODEL) {
     return process.env.OPENAI_DEFAULT_HAIKU_MODEL