diff --git a/metagpt/actions/design_api.py b/metagpt/actions/design_api.py
index 3e978f823..5f973bb60 100644
--- a/metagpt/actions/design_api.py
+++ b/metagpt/actions/design_api.py
@@ -110,7 +110,7 @@ class WriteDesign(Action):
         if not data_api_design:
             return
         pathname = self.git_repo.workdir / DATA_API_DESIGN_FILE_REPO / Path(design_doc.filename).with_suffix("")
-        await WriteDesign._save_mermaid_file(data_api_design, pathname)
+        await self._save_mermaid_file(data_api_design, pathname)
         logger.info(f"Save class view to {str(pathname)}")
 
     async def _save_seq_flow(self, design_doc):
@@ -119,13 +119,12 @@ class WriteDesign(Action):
         if not seq_flow:
             return
         pathname = self.git_repo.workdir / Path(SEQ_FLOW_FILE_REPO) / Path(design_doc.filename).with_suffix("")
-        await WriteDesign._save_mermaid_file(seq_flow, pathname)
+        await self._save_mermaid_file(seq_flow, pathname)
         logger.info(f"Saving sequence flow to {str(pathname)}")
 
     async def _save_pdf(self, design_doc):
         await self.file_repo.save_as(doc=design_doc, with_suffix=".md", relative_path=SYSTEM_DESIGN_PDF_FILE_REPO)
 
-    @staticmethod
-    async def _save_mermaid_file(data: str, pathname: Path):
+    async def _save_mermaid_file(self, data: str, pathname: Path):
         pathname.parent.mkdir(parents=True, exist_ok=True)
-        await mermaid_to_file(data, pathname)
+        await mermaid_to_file(self.config.mermaid_engine, data, pathname)
diff --git a/metagpt/actions/research.py b/metagpt/actions/research.py
index a635714ef..0af49a1cf 100644
--- a/metagpt/actions/research.py
+++ b/metagpt/actions/research.py
@@ -8,7 +8,6 @@ from typing import Callable, Optional, Union
 from pydantic import Field, parse_obj_as
 
 from metagpt.actions import Action
-from metagpt.config import CONFIG
 from metagpt.config2 import config
 from metagpt.logs import logger
 from metagpt.tools.search_engine import SearchEngine
@@ -216,9 +215,7 @@ class WebBrowseAndSummarize(Action):
         for u, content in zip([url, *urls], contents):
             content = content.inner_text
             chunk_summaries = []
-            for prompt in generate_prompt_chunk(
-                content, prompt_template, self.llm.model, system_text, CONFIG.max_tokens_rsp
-            ):
+            for prompt in generate_prompt_chunk(content, prompt_template, self.llm.model, system_text, 4096):
                 logger.debug(prompt)
                 summary = await self._aask(prompt, [system_text])
                 if summary == "Not relevant.":
diff --git a/metagpt/config2.py b/metagpt/config2.py
index 2a9611627..6345c1b8c 100644
--- a/metagpt/config2.py
+++ b/metagpt/config2.py
@@ -74,6 +74,12 @@ class Config(CLIParams, YamlModel):
     mmdc: str = "mmdc"
     puppeteer_config: str = ""
     pyppeteer_executable_path: str = ""
+    IFLYTEK_APP_ID: str = ""
+    IFLYTEK_APP_SECRET: str = ""
+    IFLYTEK_APP_KEY: str = ""
+    AZURE_TTS_SUBSCRIPTION_KEY: str = ""
+    AZURE_TTS_REGION: str = ""
+    mermaid_engine: str = "nodejs"
 
     @classmethod
     def default(cls):
diff --git a/metagpt/learn/text_to_speech.py b/metagpt/learn/text_to_speech.py
index f12e52b8e..8ffafbd0e 100644
--- a/metagpt/learn/text_to_speech.py
+++ b/metagpt/learn/text_to_speech.py
@@ -7,7 +7,6 @@
 @Desc    : Text-to-Speech skill, which provides text-to-speech functionality
 """
 
-from metagpt.config import CONFIG
 from metagpt.config2 import config
 from metagpt.const import BASE64_FORMAT
 from metagpt.tools.azure_tts import oas3_azsure_tts
@@ -45,7 +44,7 @@ async def text_to_speech(
 
     """
 
-    if (CONFIG.AZURE_TTS_SUBSCRIPTION_KEY and CONFIG.AZURE_TTS_REGION) or (subscription_key and region):
+    if subscription_key and region:
         audio_declaration = "data:audio/wav;base64,"
         base64_data = await oas3_azsure_tts(text, lang, voice, style, role, subscription_key, region)
         s3 = S3(config.s3)
@@ -53,14 +52,12 @@ async def text_to_speech(
         if url:
             return f"[{text}]({url})"
         return audio_declaration + base64_data if base64_data else base64_data
-    if (CONFIG.IFLYTEK_APP_ID and CONFIG.IFLYTEK_API_KEY and CONFIG.IFLYTEK_API_SECRET) or (
-        iflytek_app_id and iflytek_api_key and iflytek_api_secret
-    ):
+    if iflytek_app_id and iflytek_api_key and iflytek_api_secret:
         audio_declaration = "data:audio/mp3;base64,"
         base64_data = await oas3_iflytek_tts(
             text=text, app_id=iflytek_app_id, api_key=iflytek_api_key, api_secret=iflytek_api_secret
         )
-        s3 = S3()
+        s3 = S3(config.s3)
         url = await s3.cache(data=base64_data, file_ext=".mp3", format=BASE64_FORMAT)
         if url:
             return f"[{text}]({url})"
diff --git a/metagpt/tools/azure_tts.py b/metagpt/tools/azure_tts.py
index f4f8aa0a2..2e0e2267c 100644
--- a/metagpt/tools/azure_tts.py
+++ b/metagpt/tools/azure_tts.py
@@ -13,7 +13,6 @@ from uuid import uuid4
 import aiofiles
 from azure.cognitiveservices.speech import AudioConfig, SpeechConfig, SpeechSynthesizer
 
-from metagpt.config import CONFIG
 from metagpt.logs import logger
 
 
@@ -25,8 +24,8 @@ class AzureTTS:
         :param subscription_key: key is used to access your Azure AI service API, see: `https://portal.azure.com/` > `Resource Management` > `Keys and Endpoint`
         :param region: This is the location (or region) of your resource. You may need to use this field when making calls to this API.
         """
-        self.subscription_key = subscription_key if subscription_key else CONFIG.AZURE_TTS_SUBSCRIPTION_KEY
-        self.region = region if region else CONFIG.AZURE_TTS_REGION
+        self.subscription_key = subscription_key
+        self.region = region
 
     # 参数参考：https://learn.microsoft.com/zh-cn/azure/cognitive-services/speech-service/language-support?tabs=tts#voice-styles-and-roles
     async def synthesize_speech(self, lang, voice, text, output_file):
@@ -83,10 +82,6 @@ async def oas3_azsure_tts(text, lang="", voice="", style="", role="", subscripti
         role = "Girl"
     if not style:
         style = "affectionate"
-    if not subscription_key:
-        subscription_key = CONFIG.AZURE_TTS_SUBSCRIPTION_KEY
-    if not region:
-        region = CONFIG.AZURE_TTS_REGION
 
     xml_value = AzureTTS.role_style_text(role=role, style=style, text=text)
     tts = AzureTTS(subscription_key=subscription_key, region=region)
diff --git a/metagpt/tools/iflytek_tts.py b/metagpt/tools/iflytek_tts.py
index ad2395362..6ce48826b 100644
--- a/metagpt/tools/iflytek_tts.py
+++ b/metagpt/tools/iflytek_tts.py
@@ -23,7 +23,6 @@ import aiofiles
 import websockets as websockets
 from pydantic import BaseModel
 
-from metagpt.config import CONFIG
 from metagpt.logs import logger
 
 
@@ -56,9 +55,9 @@ class IFlyTekTTS(object):
         :param api_key: WebAPI argument, see: `https://console.xfyun.cn/services/tts`
         :param api_secret: WebAPI argument, see: `https://console.xfyun.cn/services/tts`
         """
-        self.app_id = app_id or CONFIG.IFLYTEK_APP_ID
-        self.api_key = api_key or CONFIG.IFLYTEK_API_KEY
-        self.api_secret = api_secret or CONFIG.API_SECRET
+        self.app_id = app_id
+        self.api_key = api_key
+        self.api_secret = api_secret
 
     async def synthesize_speech(self, text, output_file: str, voice=DEFAULT_IFLYTEK_VOICE):
         url = self._create_url()
@@ -127,14 +126,6 @@ async def oas3_iflytek_tts(text: str, voice: str = "", app_id: str = "", api_key
     :return: Returns the Base64-encoded .mp3 file data if successful, otherwise an empty string.
 
     """
-    if not app_id:
-        app_id = CONFIG.IFLYTEK_APP_ID
-    if not api_key:
-        api_key = CONFIG.IFLYTEK_API_KEY
-    if not api_secret:
-        api_secret = CONFIG.IFLYTEK_API_SECRET
-    if not voice:
-        voice = CONFIG.IFLYTEK_VOICE or DEFAULT_IFLYTEK_VOICE
 
     filename = Path(__file__).parent / (uuid.uuid4().hex + ".mp3")
     try:
diff --git a/metagpt/tools/search_engine.py b/metagpt/tools/search_engine.py
index 64388a11f..fd237d537 100644
--- a/metagpt/tools/search_engine.py
+++ b/metagpt/tools/search_engine.py
@@ -10,7 +10,6 @@ from typing import Callable, Coroutine, Literal, Optional, Union, overload
 
 from semantic_kernel.skill_definition import sk_function
 
-from metagpt.config import CONFIG
 from metagpt.tools import SearchEngineType
 
 
@@ -46,7 +45,6 @@ class SearchEngine:
         engine: Optional[SearchEngineType] = None,
         run_func: Callable[[str, int, bool], Coroutine[None, None, Union[str, list[str]]]] = None,
     ):
-        engine = engine or CONFIG.search_engine
         if engine == SearchEngineType.SERPAPI_GOOGLE:
             module = "metagpt.tools.search_engine_serpapi"
             run_func = importlib.import_module(module).SerpAPIWrapper().run
diff --git a/metagpt/utils/mermaid.py b/metagpt/utils/mermaid.py
index 893d05be0..3f6a2ef12 100644
--- a/metagpt/utils/mermaid.py
+++ b/metagpt/utils/mermaid.py
@@ -17,7 +17,7 @@ from metagpt.logs import logger
 from metagpt.utils.common import check_cmd_exists
 
 
-async def mermaid_to_file(mermaid_code, output_file_without_suffix, width=2048, height=2048) -> int:
+async def mermaid_to_file(engine, mermaid_code, output_file_without_suffix, width=2048, height=2048) -> int:
     """suffix: png/svg/pdf
 
     :param mermaid_code: mermaid code
@@ -35,7 +35,6 @@ async def mermaid_to_file(mermaid_code, output_file_without_suffix, width=2048,
         await f.write(mermaid_code)
     # tmp.write_text(mermaid_code, encoding="utf-8")
 
-    engine = config.mermaid["default"].engine
     if engine == "nodejs":
         if check_cmd_exists(config.mmdc) != 0:
             logger.warning(
diff --git a/tests/metagpt/learn/test_text_to_speech.py b/tests/metagpt/learn/test_text_to_speech.py
index aca08b9a2..41611171c 100644
--- a/tests/metagpt/learn/test_text_to_speech.py
+++ b/tests/metagpt/learn/test_text_to_speech.py
@@ -9,34 +9,43 @@
 
 import pytest
 
-from metagpt.config import CONFIG
+from metagpt.config2 import config
 from metagpt.learn.text_to_speech import text_to_speech
 
 
 @pytest.mark.asyncio
 async def test_text_to_speech():
     # Prerequisites
-    assert CONFIG.IFLYTEK_APP_ID
-    assert CONFIG.IFLYTEK_API_KEY
-    assert CONFIG.IFLYTEK_API_SECRET
-    assert CONFIG.AZURE_TTS_SUBSCRIPTION_KEY and CONFIG.AZURE_TTS_SUBSCRIPTION_KEY != "YOUR_API_KEY"
-    assert CONFIG.AZURE_TTS_REGION
+    assert config.IFLYTEK_APP_ID
+    assert config.IFLYTEK_API_KEY
+    assert config.IFLYTEK_API_SECRET
+    assert config.AZURE_TTS_SUBSCRIPTION_KEY and config.AZURE_TTS_SUBSCRIPTION_KEY != "YOUR_API_KEY"
+    assert config.AZURE_TTS_REGION
 
+    i = config.copy()
     # test azure
-    data = await text_to_speech("panda emoji")
+    data = await text_to_speech(
+        "panda emoji",
+        subscription_key=i.AZURE_TTS_SUBSCRIPTION_KEY,
+        region=i.AZURE_TTS_REGION,
+        iflytek_api_key=i.IFLYTEK_API_KEY,
+        iflytek_api_secret=i.IFLYTEK_API_SECRET,
+        iflytek_app_id=i.IFLYTEK_APP_ID,
+    )
     assert "base64" in data or "http" in data
 
     # test iflytek
     ## Mock session env
-    old_options = CONFIG.options.copy()
-    new_options = old_options.copy()
-    new_options["AZURE_TTS_SUBSCRIPTION_KEY"] = ""
-    CONFIG.set_context(new_options)
-    try:
-        data = await text_to_speech("panda emoji")
-        assert "base64" in data or "http" in data
-    finally:
-        CONFIG.set_context(old_options)
+    i.AZURE_TTS_SUBSCRIPTION_KEY = ""
+    data = await text_to_speech(
+        "panda emoji",
+        subscription_key=i.AZURE_TTS_SUBSCRIPTION_KEY,
+        region=i.AZURE_TTS_REGION,
+        iflytek_api_key=i.IFLYTEK_API_KEY,
+        iflytek_api_secret=i.IFLYTEK_API_SECRET,
+        iflytek_app_id=i.IFLYTEK_APP_ID,
+    )
+    assert "base64" in data or "http" in data
 
 
 if __name__ == "__main__":
diff --git a/tests/metagpt/tools/test_azure_tts.py b/tests/metagpt/tools/test_azure_tts.py
index a33925a5c..e856d3b27 100644
--- a/tests/metagpt/tools/test_azure_tts.py
+++ b/tests/metagpt/tools/test_azure_tts.py
@@ -11,7 +11,6 @@
 import pytest
 from azure.cognitiveservices.speech import ResultReason
 
-from metagpt.config import CONFIG
 from metagpt.config2 import config
 from metagpt.tools.azure_tts import AzureTTS
 
@@ -19,8 +18,8 @@ from metagpt.tools.azure_tts import AzureTTS
 @pytest.mark.asyncio
 async def test_azure_tts():
     # Prerequisites
-    assert CONFIG.AZURE_TTS_SUBSCRIPTION_KEY and CONFIG.AZURE_TTS_SUBSCRIPTION_KEY != "YOUR_API_KEY"
-    assert CONFIG.AZURE_TTS_REGION
+    assert config.AZURE_TTS_SUBSCRIPTION_KEY and config.AZURE_TTS_SUBSCRIPTION_KEY != "YOUR_API_KEY"
+    assert config.AZURE_TTS_REGION
 
     azure_tts = AzureTTS(subscription_key="", region="")
     text = """
diff --git a/tests/metagpt/tools/test_iflytek_tts.py b/tests/metagpt/tools/test_iflytek_tts.py
index 58d8a83ce..18af0a723 100644
--- a/tests/metagpt/tools/test_iflytek_tts.py
+++ b/tests/metagpt/tools/test_iflytek_tts.py
@@ -7,22 +7,22 @@
 """
 import pytest
 
-from metagpt.config import CONFIG
+from metagpt.config2 import config
 from metagpt.tools.iflytek_tts import oas3_iflytek_tts
 
 
 @pytest.mark.asyncio
 async def test_tts():
     # Prerequisites
-    assert CONFIG.IFLYTEK_APP_ID
-    assert CONFIG.IFLYTEK_API_KEY
-    assert CONFIG.IFLYTEK_API_SECRET
+    assert config.IFLYTEK_APP_ID
+    assert config.IFLYTEK_API_KEY
+    assert config.IFLYTEK_API_SECRET
 
     result = await oas3_iflytek_tts(
         text="你好，hello",
-        app_id=CONFIG.IFLYTEK_APP_ID,
-        api_key=CONFIG.IFLYTEK_API_KEY,
-        api_secret=CONFIG.IFLYTEK_API_SECRET,
+        app_id=config.IFLYTEK_APP_ID,
+        api_key=config.IFLYTEK_API_KEY,
+        api_secret=config.IFLYTEK_API_SECRET,
     )
     assert result
 
diff --git a/tests/metagpt/tools/test_web_browser_engine_playwright.py b/tests/metagpt/tools/test_web_browser_engine_playwright.py
index 0f2679531..32019bad9 100644
--- a/tests/metagpt/tools/test_web_browser_engine_playwright.py
+++ b/tests/metagpt/tools/test_web_browser_engine_playwright.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from metagpt.config import CONFIG
+from metagpt.config2 import config
 from metagpt.tools import web_browser_engine_playwright
 from metagpt.utils.parse_html import WebPage
 
@@ -20,11 +20,11 @@ from metagpt.utils.parse_html import WebPage
     ids=["chromium-normal", "firefox-normal", "webkit-normal"],
 )
 async def test_scrape_web_page(browser_type, use_proxy, kwagrs, url, urls, proxy, capfd):
-    global_proxy = CONFIG.global_proxy
+    global_proxy = config.proxy
     try:
         if use_proxy:
             server, proxy = await proxy
-            CONFIG.global_proxy = proxy
+            config.proxy = proxy
         browser = web_browser_engine_playwright.PlaywrightWrapper(browser_type=browser_type, **kwagrs)
         result = await browser.run(url)
         assert isinstance(result, WebPage)
@@ -39,7 +39,7 @@ async def test_scrape_web_page(browser_type, use_proxy, kwagrs, url, urls, proxy
             server.close()
             assert "Proxy:" in capfd.readouterr().out
     finally:
-        CONFIG.global_proxy = global_proxy
+        config.proxy = global_proxy
 
 
 if __name__ == "__main__":
diff --git a/tests/metagpt/tools/test_web_browser_engine_selenium.py b/tests/metagpt/tools/test_web_browser_engine_selenium.py
index 8fe365352..bd5abcb9b 100644
--- a/tests/metagpt/tools/test_web_browser_engine_selenium.py
+++ b/tests/metagpt/tools/test_web_browser_engine_selenium.py
@@ -4,7 +4,7 @@
 
 import pytest
 
-from metagpt.config import CONFIG
+from metagpt.config2 import config
 from metagpt.tools import web_browser_engine_selenium
 from metagpt.utils.parse_html import WebPage
 
@@ -23,11 +23,11 @@ async def test_scrape_web_page(browser_type, use_proxy, url, urls, proxy, capfd)
     # Prerequisites
     # firefox, chrome, Microsoft Edge
 
-    global_proxy = CONFIG.global_proxy
+    global_proxy = config.proxy
     try:
         if use_proxy:
             server, proxy = await proxy
-            CONFIG.global_proxy = proxy
+            config.proxy = proxy
         browser = web_browser_engine_selenium.SeleniumWrapper(browser_type=browser_type)
         result = await browser.run(url)
         assert isinstance(result, WebPage)
@@ -42,7 +42,7 @@ async def test_scrape_web_page(browser_type, use_proxy, url, urls, proxy, capfd)
             server.close()
             assert "Proxy:" in capfd.readouterr().out
     finally:
-        CONFIG.global_proxy = global_proxy
+        config.proxy = global_proxy
 
 
 if __name__ == "__main__":
diff --git a/tests/metagpt/utils/test_mermaid.py b/tests/metagpt/utils/test_mermaid.py
index 6345e9c51..367223332 100644
--- a/tests/metagpt/utils/test_mermaid.py
+++ b/tests/metagpt/utils/test_mermaid.py
@@ -8,7 +8,6 @@
 
 import pytest
 
-from metagpt.config import CONFIG
 from metagpt.context import CONTEXT
 from metagpt.utils.common import check_cmd_exists
 from metagpt.utils.mermaid import MMC1, mermaid_to_file
@@ -22,9 +21,8 @@ async def test_mermaid(engine):
     # playwright prerequisites: playwright install --with-deps chromium
     assert check_cmd_exists("npm") == 0
 
-    CONFIG.mermaid_engine = engine
-    save_to = CONTEXT.git_repo.workdir / f"{CONFIG.mermaid_engine}/1"
-    await mermaid_to_file(MMC1, save_to)
+    save_to = CONTEXT.git_repo.workdir / f"{engine}/1"
+    await mermaid_to_file(engine, MMC1, save_to)
 
     # ink does not support pdf
     if engine == "ink":