Improve MiniMax endpoint selection and response parsing

Update MiniMax provider and URL utilities to better handle region-specific endpoints and response formats. Changes:
- config.py: set default model to "MiniMax-M2.1" and update default API URL to the .com endpoint.
- providers/minimax.py: import re, switch to a smart endpoint selector (get_working_minimax_endpoint), update log messages, and strip <think>...</think> reasoning blocks from responses before processing.
- url_utils.py: export get_working_minimax_endpoint and implement it; this function probes MiniMax .com and .chat endpoints using an auth test (checks base_resp for status) and falls back to the domestic endpoint if none accept the key. Also update __all__ accordingly.

Rationale: MiniMax uses region/key-specific endpoints that require auth-based checks rather than simple connectivity tests. These changes improve reliability by selecting a compatible endpoint and cleaning out embedded reasoning blocks from model outputs.

Author: cafferychen777

python/mllmcelltype/config.py

@@ -63,9 +63,9 @@ class ProviderConfig:
         default_api_url="https://open.bigmodel.cn/api/paas/v4/chat/completions",
     ),
     "minimax": ProviderConfig(
-        default_model="minimax-m2.1",
+        default_model="MiniMax-M2.1",
         api_key_env_var="MINIMAX_API_KEY",
-        default_api_url="https://api.minimaxi.chat/v1/text/chatcompletion_v2",
+        default_api_url="https://api.minimaxi.com/v1/chat/completions",
     ),
     "grok": ProviderConfig(
         default_model="grok-4",

python/mllmcelltype/providers/minimax.py

@@ -3,12 +3,13 @@
 from __future__ import annotations
 
 import json
+import re
 import time
 
 import requests
 
 from ..logger import write_log
-from ..url_utils import get_default_api_url, validate_base_url
+from ..url_utils import get_working_minimax_endpoint, validate_base_url
 
 
 def process_minimax(
@@ -34,15 +35,15 @@ def process_minimax(
         write_log(error_msg, level="error")
         raise ValueError(error_msg)
 
-    # Use custom URL or default URL
+    # Use custom URL or smart selection
     if base_url:
         if not validate_base_url(base_url):
             raise ValueError(f"Invalid base URL: {base_url}")
         url = base_url
         write_log(f"Using custom base URL: {url}")
     else:
-        url = get_default_api_url("minimax")
-        write_log(f"Using default URL: {url}")
+        url = get_working_minimax_endpoint(api_key)
+        write_log(f"Using smart-selected endpoint: {url}")
 
     write_log(f"Using model: {model}")
     write_log(f"API URL: {url}")
@@ -119,6 +120,10 @@ def process_minimax(
                 and "content" in choices[0]["message"]
             ):
                 response_content = choices[0]["message"]["content"]
+                # Strip <think>...</think> reasoning block (MiniMax M2.1 Coding Plan)
+                response_content = re.sub(
+                    r"<think>[\s\S]*?</think>\s*", "", response_content
+                )
                 res = response_content.strip().split("\n")
             else:
                 write_log(f"Unexpected response format: {content}")

python/mllmcelltype/url_utils.py

@@ -9,7 +9,13 @@
 
 # Re-export get_default_api_url for backward compatibility
 # The actual implementation is in config.py (Single Source of Truth)
-__all__ = ["get_default_api_url", "get_working_qwen_endpoint", "resolve_provider_base_url", "validate_base_url"]
+__all__ = [
+    "get_default_api_url",
+    "get_working_minimax_endpoint",
+    "get_working_qwen_endpoint",
+    "resolve_provider_base_url",
+    "validate_base_url",
+]
 
 
 def resolve_provider_base_url(provider: str, base_urls: str | dict | None) -> str | None:
@@ -54,6 +60,64 @@ def validate_base_url(url: str) -> bool:
     return url.startswith("http://") or url.startswith("https://")
 
 
+def get_working_minimax_endpoint(api_key: str) -> str:
+    """Smart endpoint selection for MiniMax.
+
+    MiniMax has region-specific endpoints that only accept keys issued for
+    that region (e.g. Coding Plan ``sk-cp-`` keys work on the domestic
+    ``.com`` endpoint but not on the international ``.chat`` endpoint).
+    Unlike Qwen where any key works on any reachable endpoint, MiniMax
+    requires matching the key to its endpoint, so we test authentication
+    rather than mere connectivity.
+
+    Args:
+        api_key: MiniMax API key
+
+    Returns:
+        Working endpoint URL
+    """
+    endpoints = [
+        "https://api.minimaxi.com/v1/chat/completions",   # Domestic (China)
+        "https://api.minimaxi.chat/v1/chat/completions",  # International
+    ]
+
+    write_log("Testing MiniMax endpoint compatibility...", level="debug")
+
+    for endpoint in endpoints:
+        try:
+            headers = {"Authorization": f"Bearer {api_key}", "Content-Type": "application/json"}
+            test_body = {
+                "model": "MiniMax-M2.1",
+                "messages": [{"role": "user", "content": "test"}],
+                "max_tokens": 1,
+            }
+            response = requests.post(endpoint, headers=headers, json=test_body, timeout=5)
+
+            # MiniMax returns HTTP 200 even for auth errors; check base_resp
+            if response.status_code == 200:
+                data = response.json()
+                base_resp = data.get("base_resp", {})
+                status_code = base_resp.get("status_code", 0)
+                if status_code == 0:
+                    write_log(f"MiniMax endpoint accepted key: {endpoint}", level="debug")
+                    return endpoint
+                write_log(
+                    f"MiniMax endpoint rejected key ({base_resp.get('status_msg', '')}): {endpoint}",
+                    level="debug",
+                )
+            else:
+                write_log(
+                    f"MiniMax endpoint returned HTTP {response.status_code}: {endpoint}",
+                    level="debug",
+                )
+        except Exception:
+            write_log(f"MiniMax endpoint unreachable: {endpoint}", level="debug")
+
+    # Fallback to domestic endpoint
+    write_log("No MiniMax endpoint accepted the key, using domestic endpoint as fallback")
+    return endpoints[0]
+
+
 def get_working_qwen_endpoint(api_key: str) -> str:
     """Smart endpoint selection for Qwen.