dify-mcp-client

MCP Client as Agent Strategy Plugin.

[!IMPORTANT] Dify is not MCP Server but MCP Host.

How it works

Currently, each MCP client (ReAct Agent) node can connect a stdio MCP server.

1. Tool, Resource, Prompt lists are converted into Dify Tools.
2. Your selected LLM can see their name, description, argument type
3. The LLM calls Tools based on the ReAct loop (Reason → Act → Observe).

[!NOTE] Most of the code in this repository contains the following files.

Dify Official Plugins / Agent Strategies

https://github.com/langgenius/dify-official-plugins/tree/main/agent-strategies/cot_agent

What I did

• Copied ReAct.py and renamed file as mcpReAct.py
• Added config_json GUI input field by editing mcpReAct.yaml and class mcpReActParams()

in mcpReAct.py, I added

• New 12 functions for MCP
• __init__() for initializing AsyncExitStack and event loop
• Some codes in _handle_invoke_action() for MCP
• MCP setup and cleanup in _invoke()

[!IMPORTANT] ReAct while loop is as they are

Caution and Limitation

[!CAUTION] This plugin does not implement a human-in-the-loop mechanism by default, so connect reliable mcp server only. To avoid it, decrease max itereations(default:3) to 1, and use this Agent node repeatedly in Chatflow. However, agent memory is reset by the end of Workflow. Use Conversaton Variable to save history and pass it to QUERY.
Don't forget to add a phrase such as "ask for user's permission when calling tools" in INSTRUCTION.

[!WARNING]

• The Tools field should not be left blank. so select Dify tools like "current time".
• The SSE connection is not supported

How to use plugin

[!WARNING]

Only source code deploy is supported

steps are as follows.

            > [how-to-develop-and-deploy-plugin](https://github.com/3dify-project/dify-mcp-client?tab=readme-ov-file#how-to-develop-and-deploy-plugin)

• PATH for module like "npx" is essential to awake stdio MCP server.
• Default windows command prompt that knows npx PATH.
• By executing python -m main(plugin install command) in the CLI, MCP plugin works well.
• .difypkg is useful, but codes are executed at built-in python environment which means module PATH is not available.
• If you any plans or ideas, welcome to issue. https://github.com/3dify-project/dify-mcp-client/issues/1

Install plugin from GitHub (online) -> Not supported yet

• Enter the following GitHub repository name

https://github.com/3dify-project/dify-mcp-client/

• Dify > PLUGINS > + Install plugin > INSTALL FROM > GitHub

Install plugin from .difypkg file (offline) -> Not supported yet

• Go to Releases https://github.com/3dify-project/dify-mcp-client/releases
• Select suitable version of .difypkg
• Dify > PLUGINS > + Install plugin > INSTALL FROM > Local Package File

How to handle errors when installing plugins?

Issue: If you encounter the error message: plugin verification has been enabled, and the plugin you want to install has a bad signature, how to handle the issue? Solution: Add the following line to the end of your /docker/.env configuration file:

FORCE_VERIFYING_SIGNATURE=false

Run the following commands to restart the Dify service:

cd docker
docker compose down
docker compose up -d

Once this field is added, the Dify platform will allow the installation of all plugins that are not listed (and thus not verified) in the Dify Marketplace.

[!TIP] Marketplace need Approval. If stars☆ reach 100, I'll consider to make PR for them.

Where does this plugin show up?

• It takes few minutes to install

            - Once installed, you can use it any workflows as Agent node
  

• Select "mcpReAct" strategy (otherwise no MCP)

Compatible claude_desktop_config.json

MCP Agent Plugin node require config_json like this to command to awake an MCP server

{
    "mcpservers":{
        "name_of_mcpserver":{
            "command": "npx",
            "args": ["arg1", "arg2"]
        },
    }
}

[!WARNING]

• Currently support one MCP server per Agent node
• npx.cmd instead of npx if you use Windows
• npx command needs global install of Node.js

Chatflow Example

I provide this Dify ChatFlow for testing dify mcp plugin as .yml.

https://github.com/3dify-project/dify-mcp-client/tree/main/test/chatflow

After download DSL(yml) file, import it in Dify and you can test MCP using "Everything MCP server"

https://github.com/modelcontextprotocol/servers/tree/main/src/everything

How to develop and deploy plugin

General plugin dev guide

https://github.com/3dify-project/dify-mcp-client/blob/main/GUIDE.md

Dify plugin SDK daemon

In my case (Windows 11) ,need to download dify-plugin-windows-amd64.exe (v0.0.3) Choose your OS-compatible verson at here: https://github.com/langgenius/dify-plugin-daemon/releases Rename it as dify.exe

Reference

https://docs.dify.ai/plugins/quick-start/develop-plugins/initialize-development-tools

[!NOTE] You can skip this stage if you pull or download codes of this repo

dify plugin init

Initial settings are as follow

Install python module

Python3.12+ is compatible. Dify plugin official installation guide use pip, but I used uv.

uv init --python=python3.12
.venv\Scripts\activate

Install python modules for plugin development

uv add werkzeug==3.0.3
uv add flask
uv add dify_plugin

            
        
            
                ```

### Copy and rename env.example to .env
I changed `REMOTE_INSTALL_HOST` from `debug.dify.ai` to `localhost` 
(Docker Compose environment)
click bug icon button to see these information

### Change directory

cd mcp_client

### Do Once

pip install -r requirements.txt

### Activate Dify plugin

python -m main

(ctrl+C to stop)
> [!TIP]
> REMOTE_INSTALL_KEY of .env often changes.
> If you encounter error messages like `handshake failed, invalid key`, renew it.


## Useful GitHub repositories for developers

#### Dify Plugin SDKs
https://github.com/langgenius/dify-plugin-sdks

#### MCP Python SDK
https://github.com/modelcontextprotocol/python-sdk


> [!TIP]
> Especially useful following MCP client example
> https://github.com/modelcontextprotocol/python-sdk/blob/main/examples/clients/simple-chatbot/mcp_simple_chatbot/main.py

> [!NOTE]
> Dify plugin has `requirements.txt` which automatically installs python modules.
> I include `mcp` in it, so you don't need to download the MCP SDK separately.