diff --git a/lib/ai/providers/gemini-image.ts b/lib/ai/providers/gemini-image.ts
index b3c5c5fb1..b507a3940 100644
--- a/lib/ai/providers/gemini-image.ts
+++ b/lib/ai/providers/gemini-image.ts
@@ -716,12 +716,11 @@ async function sendGrsaiGptImageRequest(params: {
         response.status,
         responseText.substring(0, 1000)
       );
+      const providerError = getGrsaiErrorMessage(data);
       const errorMessage =
-        data?.error?.message ||
-        data?.message ||
-        data?.error ||
-        responseText ||
-        `${response.status} ${response.statusText}`;
+        providerError !== "未知错误"
+          ? providerError
+          : responseText || `${response.status} ${response.statusText}`;
       throw new Error(`图片生成失败: ${errorMessage}`);
     }
 
@@ -754,6 +753,13 @@ async function sendGrsaiGptImageRequest(params: {
           timeoutLabel: "Grsai GPT Image",
         });
       }
+
+      const providerError = getGrsaiErrorMessage(data);
+      throw new Error(
+        `图片生成失败: 未返回任务 ID 或可用图片${
+          providerError !== "未知错误" ? `: ${providerError}` : ""
+        }`
+      );
     }
 
     return data;
@@ -857,18 +863,46 @@ function getGrsaiProgress(payload: any): number | null {
 
 function getGrsaiErrorMessage(payload: any): string {
   const normalized = normalizeGrsaiPayload(payload);
+  const normalizePart = (part: unknown) => {
+    if (typeof part === "string" || typeof part === "number") {
+      return String(part).trim();
+    }
+    if (!isRecord(part)) return "";
+    return String(
+      part.message ||
+        part.msg ||
+        part.detail ||
+        part.reason ||
+        part.code ||
+        part.type ||
+        ""
+    ).trim();
+  };
   const messages = [
     normalized?.failure_reason,
+    normalized?.error?.message,
+    normalized?.error?.msg,
+    normalized?.error?.code,
     normalized?.error,
     normalized?.message,
+    normalized?.msg,
+    normalized?.detail,
+    normalized?.reason,
+    normalized?.code,
+    payload?.error?.message,
+    payload?.error?.msg,
+    payload?.error?.code,
     payload?.msg,
     payload?.message,
     payload?.error,
+    payload?.detail,
+    payload?.reason,
+    payload?.code,
   ]
-    .map((part) => String(part || "").trim())
+    .map(normalizePart)
     .filter(Boolean);
 
-  return messages.join(" / ") || "未知错误";
+  return Array.from(new Set(messages)).join(" / ") || "未知错误";
 }
 
 function hasGrsaiImages(payload: any): boolean {
@@ -899,18 +933,36 @@ async function fetchWithTimeout(
 
 async function readJsonResponse(response: Response, label: string): Promise<any> {
   const text = await response.text();
+  const payload = parseGrsaiJsonOrStreamResponse(text);
 
   if (!response.ok) {
     logger.error(`${label} failed:`, response.status, text.substring(0, 500));
-    throw new Error(`${label} 接口错误：${response.status} ${response.statusText}`);
+    const providerError = getGrsaiErrorMessage(payload);
+    const detail =
+      providerError !== "未知错误"
+        ? providerError
+        : String(payload?.raw || text || "").trim().slice(0, 300);
+    throw new Error(
+      `${label} 接口错误：${response.status} ${response.statusText}${
+        detail ? `: ${detail}` : ""
+      }`
+    );
   }
 
-  try {
-    return JSON.parse(text);
-  } catch (error) {
+  if (isRecord(payload) && !("raw" in payload)) {
+    return payload;
+  }
+
+  if (!isRecord(payload)) {
+    return payload;
+  }
+
+  if ("raw" in payload) {
     logger.error(`${label} returned non-JSON response:`, text.substring(0, 500));
     throw new Error(`${label} 返回格式异常，未能解析任务结果`);
   }
+
+  return payload;
 }
 
 async function pollGrsaiNanoBananaResult(params: {
@@ -1047,11 +1099,16 @@ async function submitAndPollGrsaiNanoBanana(params: {
 
   const taskId = getGrsaiTaskId(submitPayload);
   if (!taskId) {
+    const providerError = getGrsaiErrorMessage(submitPayload);
     logger.error(
       `${params.apiLogPrefix} Async submit response has no task id:`,
       JSON.stringify(submitPayload).substring(0, 500)
     );
-    throw new Error("GRSAI Nano Banana 异步任务提交失败：未返回任务 ID");
+    throw new Error(
+      `GRSAI Nano Banana 异步任务提交失败：未返回任务 ID${
+        providerError !== "未知错误" ? `: ${providerError}` : ""
+      }`
+    );
   }
 
   logger.debug(`${params.apiLogPrefix} Async task submitted:`, { taskId });
diff --git a/lib/ai/runtime/model-health.ts b/lib/ai/runtime/model-health.ts
index 765cf910c..8ab443831 100644
--- a/lib/ai/runtime/model-health.ts
+++ b/lib/ai/runtime/model-health.ts
@@ -151,7 +151,10 @@ export function classifyAiModelHealthFailure(error: unknown): {
 
   if (
     normalized.includes("insufficient balance") ||
+    normalized.includes("insufficient credit") ||
     normalized.includes("credits insufficient") ||
+    normalized.includes("credit insufficient") ||
+    normalized.includes("not enough credit") ||
     normalized.includes("quota") ||
     normalized.includes("余额") ||
     normalized.includes("额度") ||
@@ -209,10 +212,38 @@ export function classifyAiModelHealthFailure(error: unknown): {
     };
   }
 
+  if (
+    normalized.includes("未返回任务 id") ||
+    normalized.includes("未返回任务id") ||
+    normalized.includes("no task id") ||
+    normalized.includes("missing task id") ||
+    normalized.includes("provider error") ||
+    normalized.includes("provider_error") ||
+    normalized.includes("provider request failed") ||
+    normalized.includes("provider task failed") ||
+    normalized.includes("upstream error") ||
+    normalized.includes("upstream_error") ||
+    normalized.includes("upstream request failed") ||
+    normalized.includes("上游服务错误") ||
+    normalized.includes("上游接口错误")
+  ) {
+    return {
+      eventType: "unavailable",
+      severity: "critical",
+      counted: true,
+      reason: "provider_execution_failed",
+    };
+  }
+
   if (
     normalized.includes("download") ||
     normalized.includes("no image url") ||
     normalized.includes("no image") ||
+    normalized.includes("empty result") ||
+    normalized.includes("empty response") ||
+    normalized.includes("空结果") ||
+    normalized.includes("返回结果为空") ||
+    normalized.includes("响应为空") ||
     normalized.includes("未返回可用图片") ||
     normalized.includes("未包含可用图片") ||
     normalized.includes("未解析到图片") ||
@@ -245,14 +276,21 @@ export function shouldFailoverAiModelError(error: unknown) {
     normalized.includes("snapgen 任务已完成但未返回图片地址") ||
     normalized.includes("snapgen 未返回可用图片");
 
-  if (imageProviderTaskFailed) {
-    return true;
-  }
+  const providerExecutionFailed =
+    classification.reason === "provider_execution_failed" ||
+    normalized.includes("未返回任务 id") ||
+    normalized.includes("未返回任务id") ||
+    normalized.includes("no task id") ||
+    normalized.includes("missing task id");
 
   if (classification.reason === "user_cancelled" || classification.reason === "non_provider_failure") {
     return false;
   }
 
+  if (imageProviderTaskFailed || providerExecutionFailed) {
+    return true;
+  }
+
   if (
     classification.eventType === "timeout" ||
     classification.reason === "transport_failure_no_provider_response"
@@ -263,6 +301,11 @@ export function shouldFailoverAiModelError(error: unknown) {
   if (classification.eventType === "download_error") {
     return (
       normalized.includes("no image") ||
+      normalized.includes("empty result") ||
+      normalized.includes("empty response") ||
+      normalized.includes("空结果") ||
+      normalized.includes("返回结果为空") ||
+      normalized.includes("响应为空") ||
       normalized.includes("未返回可用图片") ||
       normalized.includes("未包含可用图片") ||
       normalized.includes("未解析到图片") ||