diff --git a/metagpt/actions/research.py b/metagpt/actions/research.py
index 65962de31..2a99a8d99 100644
--- a/metagpt/actions/research.py
+++ b/metagpt/actions/research.py
@@ -134,7 +134,7 @@ class CollectLinks(Action):
                     break
 
         model_name = config.llm.model
-        prompt = reduce_message_length(gen_msg(), model_name, system_text, 0)
+        prompt = reduce_message_length(gen_msg(), model_name, system_text, config.llm.max_token)
         logger.debug(prompt)
         queries = await self._aask(prompt, [system_text])
         try:
diff --git a/metagpt/config2.py b/metagpt/config2.py
index 25569bd93..ed1d23fa5 100644
--- a/metagpt/config2.py
+++ b/metagpt/config2.py
@@ -134,3 +134,4 @@ def merge_dict(dicts: Iterable[Dict]) -> Dict:
     return result
 
 
+config = Config.default()
diff --git a/tests/mock/mock_llm.py b/tests/mock/mock_llm.py
index 9c159b4ed..b2052e2b3 100644
--- a/tests/mock/mock_llm.py
+++ b/tests/mock/mock_llm.py
@@ -1,14 +1,13 @@
 import json
 from typing import Optional, Union
 
-from metagpt.config2 import Config
+from metagpt.config2 import config
 from metagpt.configs.llm_config import LLMType
 from metagpt.logs import logger
 from metagpt.provider.azure_openai_api import AzureOpenAILLM
 from metagpt.provider.openai_api import OpenAILLM
 from metagpt.schema import Message
 
-config = Config.default()
 OriginalLLM = OpenAILLM if config.llm.api_type == LLMType.OPENAI else AzureOpenAILLM