diff --git a/CLAUDE.md b/CLAUDE.md
index 5ac43a3a5..b27131b4e 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -658,6 +658,20 @@ WITH latest_prices AS (
 SELECT ... LIMIT 50 OFFSET 0;
 ```
 
+### 10. Database MCP
+
+Objective:
+You are required to use the `db` MCP server to interact with a database.
+
+Capabilities:
+With this server, you can perform the following actions:
+
+- View the structure of database tables.
+- Query and inspect data within the tables.
+
+Prerequisite:
+Before performing any operations, you must first consult the database schema definition to understand its structure. The schema is defined in the following file: @src/drizzle/schema.ts.
+
 ## 常见任务
 
 ### 添加新的供应商类型
diff --git a/src/app/v1/_lib/proxy/provider-selector.ts b/src/app/v1/_lib/proxy/provider-selector.ts
index e7e2bb268..e65b2697b 100644
--- a/src/app/v1/_lib/proxy/provider-selector.ts
+++ b/src/app/v1/_lib/proxy/provider-selector.ts
@@ -6,6 +6,7 @@ import { isCircuitOpen, getCircuitState } from "@/lib/circuit-breaker";
 import { ProxyResponses } from "./responses";
 import { logger } from "@/lib/logger";
 import type { ProxySession } from "./session";
+import type { ClientFormat } from "./format-mapper";
 import type { ProviderChainItem } from "@/types/message";
 
 /**
@@ -87,6 +88,44 @@ function providerSupportsModel(provider: Provider, requestedModel: string): bool
   return false;
 }
 
+/**
+ * 根据原始请求格式限制可选供应商类型
+ *
+ * 核心逻辑：确保客户端请求格式与供应商类型兼容，避免格式错配
+ *
+ * 映射关系：
+ * - claude → claude | claude-auth
+ * - response → codex
+ * - openai → openai-compatible
+ * - gemini → gemini
+ * - gemini-cli → gemini-cli
+ *
+ * @param format - 客户端请求格式（从 session.originalFormat 获取）
+ * @param providerType - 供应商类型
+ * @returns 是否兼容
+ *
+ * 向后兼容：调用方在 originalFormat 未设置时应跳过此检查
+ */
+function checkFormatProviderTypeCompatibility(
+  format: ClientFormat,
+  providerType: Provider["providerType"]
+): boolean {
+  switch (format) {
+    case "claude":
+      return providerType === "claude" || providerType === "claude-auth";
+    case "response":
+      return providerType === "codex";
+    case "openai":
+      return providerType === "openai-compatible";
+    case "gemini":
+      return providerType === "gemini";
+    case "gemini-cli":
+      return providerType === "gemini-cli";
+    default:
+      return true; // 未知格式回退为兼容（不会主动过滤）
+  }
+}
+
 export class ProxyProviderResolver {
   static async ensure(
     session: ProxySession,
@@ -115,7 +154,9 @@ export class ProxyProviderResolver {
         decisionContext: {
           totalProviders: 0, // 复用不需要筛选
           enabledProviders: 0,
-          targetType: reusedProvider.providerType as "claude" | "codex",
+          targetType: reusedProvider.providerType as NonNullable<
+            ProviderChainItem["decisionContext"]
+          >["targetType"],
           requestedModel: session.getCurrentModel() || "",
           groupFilterApplied: false,
           beforeHealthCheck: 0,
@@ -196,7 +237,9 @@ export class ProxyProviderResolver {
               : {
                   totalProviders: 0,
                   enabledProviders: 0,
-                  targetType: session.provider.providerType as "claude" | "codex",
+                  targetType: session.provider.providerType as NonNullable<
+                    ProviderChainItem["decisionContext"]
+                  >["targetType"],
                   requestedModel: session.getCurrentModel() || "",
                   groupFilterApplied: false,
                   beforeHealthCheck: 0,
@@ -251,7 +294,9 @@ export class ProxyProviderResolver {
             decisionContext: successContext || {
               totalProviders: 0,
               enabledProviders: 0,
-              targetType: session.provider.providerType as "claude" | "codex",
+              targetType: session.provider.providerType as NonNullable<
+                ProviderChainItem["decisionContext"]
+              >["targetType"],
               requestedModel: session.getCurrentModel() || "",
               groupFilterApplied: false,
               beforeHealthCheck: 0,
@@ -399,11 +444,29 @@ export class ProxyProviderResolver {
     const allProviders = await findProviderList();
     const requestedModel = session?.getCurrentModel() || "";
 
+    // 原始请求格式映射到目标供应商类型；缺省为 claude 以兼容历史请求
+    const targetType: "claude" | "codex" | "openai-compatible" | "gemini" | "gemini-cli" = (() => {
+      switch (session?.originalFormat) {
+        case "claude":
+          return "claude";
+        case "response":
+          return "codex";
+        case "openai":
+          return "openai-compatible";
+        case "gemini":
+          return "gemini";
+        case "gemini-cli":
+          return "gemini-cli";
+        default:
+          return "claude"; // 默认回退到 claude（向后兼容）
+      }
+    })();
+
     // === 初始化决策上下文 ===
     const context: NonNullable<ProviderChainItem["decisionContext"]> = {
       totalProviders: allProviders.length,
       enabledProviders: 0,
-      targetType: requestedModel.startsWith("claude-") ? "claude" : "codex", // 根据模型名推断
+      targetType, // 根据原始请求格式推断目标供应商类型（修复：不再根据模型名推断）
       requestedModel, // 新增：记录请求的模型
       groupFilterApplied: false,
       beforeHealthCheck: 0,
@@ -415,14 +478,26 @@ export class ProxyProviderResolver {
       excludedProviderIds: excludeIds.length > 0 ? excludeIds : undefined,
     };
 
-    // Step 1: 基础过滤 + 模型匹配（新逻辑）
+    // Step 1: 基础过滤 + 格式/模型匹配（新逻辑）
     const enabledProviders = allProviders.filter((provider) => {
       // 1a. 基础过滤
       if (!provider.isEnabled || excludeIds.includes(provider.id)) {
         return false;
       }
 
-      // 1b. 模型匹配（新逻辑）
+      // 1b. 格式类型匹配（新增）
+      // 根据 session.originalFormat 限制候选供应商类型，避免格式错配
+      if (session?.originalFormat) {
+        const isFormatCompatible = checkFormatProviderTypeCompatibility(
+          session.originalFormat,
+          provider.providerType
+        );
+        if (!isFormatCompatible) {
+          return false; // 过滤掉格式不兼容的供应商
+        }
+      }
+
+      // 1c. 模型匹配（保留原有逻辑）
       if (!requestedModel) {
         // 没有模型信息时，只选择 Anthropic 提供商（向后兼容）
         return provider.providerType === "claude";
@@ -440,6 +515,7 @@ export class ProxyProviderResolver {
           | "circuit_open"
           | "rate_limited"
           | "excluded"
+          | "format_type_mismatch"
           | "type_mismatch"
           | "model_not_allowed"
           | "disabled" = "disabled";
@@ -451,6 +527,12 @@ export class ProxyProviderResolver {
         } else if (excludeIds.includes(p.id)) {
           reason = "excluded";
           details = "已在前序尝试中失败";
+        } else if (
+          session?.originalFormat &&
+          !checkFormatProviderTypeCompatibility(session.originalFormat, p.providerType)
+        ) {
+          reason = "format_type_mismatch";
+          details = `原始格式 ${session.originalFormat} 与供应商类型 ${p.providerType} 不兼容`;
         } else if (requestedModel && !providerSupportsModel(p, requestedModel)) {
           reason = "model_not_allowed";
           details = `不支持模型 ${requestedModel}`;
diff --git a/src/app/v1/_lib/proxy/response-handler.ts b/src/app/v1/_lib/proxy/response-handler.ts
index bfc0b34aa..2b1f2fea5 100644
--- a/src/app/v1/_lib/proxy/response-handler.ts
+++ b/src/app/v1/_lib/proxy/response-handler.ts
@@ -1103,7 +1103,10 @@ function parseUsageFromResponseText(
     // Fallback to SSE parsing when body is not valid JSON
   }
 
-  if (!usageMetrics && responseText.includes("event:")) {
+  // SSE 解析：支持两种格式
+  // 1. 标准 SSE (event: + data:) - Claude/OpenAI
+  // 2. 纯 data: 格式 - Gemini
+  if (!usageMetrics && responseText.includes("data:")) {
     const events = parseSSEData(responseText);
     for (const event of events) {
       if (usageMetrics) {
diff --git a/src/lib/utils/sse.ts b/src/lib/utils/sse.ts
index a4fa4dfe0..efed88b7e 100644
--- a/src/lib/utils/sse.ts
+++ b/src/lib/utils/sse.ts
@@ -10,7 +10,9 @@ export function parseSSEData(sseText: string): ParsedSSEEvent[] {
   let dataLines: string[] = [];
 
   const flushEvent = () => {
-    if (!eventName || dataLines.length === 0) {
+    // 修改：支持没有 event: 前缀的纯 data: 格式（Gemini 流式响应）
+    // 如果没有 eventName，使用默认值 "message"
+    if (dataLines.length === 0) {
       eventName = "";
       dataLines = [];
       return;
@@ -20,9 +22,9 @@ export function parseSSEData(sseText: string): ParsedSSEEvent[] {
 
     try {
       const data = JSON.parse(dataStr);
-      events.push({ event: eventName, data });
+      events.push({ event: eventName || "message", data });
     } catch {
-      events.push({ event: eventName, data: dataStr });
+      events.push({ event: eventName || "message", data: dataStr });
     }
 
     eventName = "";
diff --git a/src/types/message.ts b/src/types/message.ts
index 4048969c1..0c89315ae 100644
--- a/src/types/message.ts
+++ b/src/types/message.ts
@@ -91,7 +91,7 @@ export interface ProviderChainItem {
     // --- 供应商池状态 ---
     totalProviders: number; // 系统总供应商数
     enabledProviders: number; // 启用的供应商数
-    targetType: "claude" | "codex"; // 目标类型
+    targetType: "claude" | "codex" | "openai-compatible" | "gemini" | "gemini-cli"; // 目标类型（基于请求格式推断）
     requestedModel?: string; // 请求的模型名称（用于追踪）
 
     // --- 用户分组筛选 ---
@@ -113,6 +113,7 @@ export interface ProviderChainItem {
         | "circuit_open"
         | "rate_limited"
         | "excluded"
+        | "format_type_mismatch" // 请求格式与供应商类型不兼容
         | "type_mismatch"
         | "model_not_allowed"
         | "disabled";