fix(chat): simplify header cards and llm fallback

agent_core/llm_provider.py

@@ -1,7 +1,7 @@
 from dataclasses import dataclass
 import json
 import os
-from urllib.error import URLError
+from urllib.error import HTTPError, URLError
 from urllib.request import Request, urlopen
 
 
@@ -75,12 +75,28 @@ class OpenAICompatibleProvider:
         if response_format:
             payload["response_format"] = response_format
         try:
-            data = _post_json(
-                base_url=self.base_url,
-                endpoint="chat/completions",
-                api_key=self.api_key,
-                payload=payload,
-            )
+            try:
+                data = _post_json(
+                    base_url=self.base_url,
+                    endpoint="chat/completions",
+                    api_key=self.api_key,
+                    payload=payload,
+                )
+            except RuntimeError as exc:
+                # 部分 OpenAI 兼容供应商或模型不支持 response_format。
+                # 保留结构化优先，遇到 400 时退回普通对话，避免演示链路被接口能力差异阻断。
+                if not response_format or "HTTP Error 400" not in str(exc):
+                    raise
+                fallback_payload = {
+                    "model": self.model_name,
+                    "messages": messages,
+                }
+                data = _post_json(
+                    base_url=self.base_url,
+                    endpoint="chat/completions",
+                    api_key=self.api_key,
+                    payload=fallback_payload,
+                )
             choice = data.get("choices", [{}])[0]
             content = choice.get("message", {}).get("content", "")
             return LLMResponse(
@@ -197,5 +213,11 @@ def _post_json(base_url: str, endpoint: str, api_key: str, payload: dict) -> dic
     try:
         with urlopen(request, timeout=60) as response:
             return json.loads(response.read().decode("utf-8"))
+    except HTTPError as exc:
+        error_body = exc.read().decode("utf-8", errors="ignore")
+        error_detail = f"{exc}"
+        if error_body:
+            error_detail = f"{error_detail} {error_body}"
+        raise RuntimeError(f"OpenAI 兼容接口调用失败：{error_detail}") from exc
     except URLError as exc:
         raise RuntimeError(f"OpenAI 兼容接口调用失败：{exc}") from exc