Chapter 4: Tool Calling and MCP Integration

April 13, 2026 · View on GitHub

Welcome to Chapter 4: Tool Calling and MCP Integration. In this part of Qwen-Agent Tutorial: Tool-Enabled Agent Framework with MCP, RAG, and Multi-Modal Workflows, you will build an intuitive mental model first, then move into concrete implementation details and practical production tradeoffs.

This chapter explains capability expansion through tools and MCP services.

Learning Goals

implement function-calling and custom tool patterns
configure MCP servers for external tool access
secure filesystem/database boundaries in MCP configs
test MCP workflows with deterministic examples

Integration Strategy

start from known-good MCP configuration blocks
add only required servers and permissions
verify tool outputs with integration scripts before production use

Source References

Summary

You now have a practical model for tool + MCP integration in Qwen-Agent.

Next: Chapter 5: Memory, RAG, and Long-Context Workflows

Source Code Walkthrough

`qwen_server/workstation_server.py`

The layout_to_right function in qwen_server/workstation_server.py handles a key part of this chapter's functionality:



def layout_to_right(text):
    return text, text


def download_text(text):
    now = datetime.datetime.now()
    current_time = now.strftime('%Y-%m-%d_%H-%M-%S')
    filename = f'file_{current_time}.md'
    save_path = os.path.join(server_config.path.download_root, filename)
    try:
        save_text_to_file(save_path, text)
        gr.Info(f'Saved to {save_path}')
    except Exception as ex:
        gr.Error(f'Failed to save this file.\n {str(ex)}')


def choose_plugin(chosen_plugin):
    if chosen_plugin == CI_OPTION:
        gr.Info('Code execution is NOT sandboxed. Do NOT ask Qwen to perform dangerous tasks.')
    if chosen_plugin == CI_OPTION or chosen_plugin == DOC_OPTION:
        return gr.update(interactive=True), None
    else:
        return gr.update(interactive=False), None


def pure_bot(history):
    if not history:
        yield history
    else:
        history[-1][1] = ''

This function is important because it defines how Qwen-Agent Tutorial: Tool-Enabled Agent Framework with MCP, RAG, and Multi-Modal Workflows implements the patterns covered in this chapter.

`qwen_server/workstation_server.py`

The download_text function in qwen_server/workstation_server.py handles a key part of this chapter's functionality:



def download_text(text):
    now = datetime.datetime.now()
    current_time = now.strftime('%Y-%m-%d_%H-%M-%S')
    filename = f'file_{current_time}.md'
    save_path = os.path.join(server_config.path.download_root, filename)
    try:
        save_text_to_file(save_path, text)
        gr.Info(f'Saved to {save_path}')
    except Exception as ex:
        gr.Error(f'Failed to save this file.\n {str(ex)}')


def choose_plugin(chosen_plugin):
    if chosen_plugin == CI_OPTION:
        gr.Info('Code execution is NOT sandboxed. Do NOT ask Qwen to perform dangerous tasks.')
    if chosen_plugin == CI_OPTION or chosen_plugin == DOC_OPTION:
        return gr.update(interactive=True), None
    else:
        return gr.update(interactive=False), None


def pure_bot(history):
    if not history:
        yield history
    else:
        history[-1][1] = ''
        message = [{'role': 'user', 'content': history[-1][0].text, 'name': 'pure_chat_user'}]
        try:
            llm = get_chat_model(llm_config)
            response = llm.chat(messages=app_global_para['pure_messages'] + message)

This function is important because it defines how Qwen-Agent Tutorial: Tool-Enabled Agent Framework with MCP, RAG, and Multi-Modal Workflows implements the patterns covered in this chapter.

`qwen_server/workstation_server.py`

The choose_plugin function in qwen_server/workstation_server.py handles a key part of this chapter's functionality:



def choose_plugin(chosen_plugin):
    if chosen_plugin == CI_OPTION:
        gr.Info('Code execution is NOT sandboxed. Do NOT ask Qwen to perform dangerous tasks.')
    if chosen_plugin == CI_OPTION or chosen_plugin == DOC_OPTION:
        return gr.update(interactive=True), None
    else:
        return gr.update(interactive=False), None


def pure_bot(history):
    if not history:
        yield history
    else:
        history[-1][1] = ''
        message = [{'role': 'user', 'content': history[-1][0].text, 'name': 'pure_chat_user'}]
        try:
            llm = get_chat_model(llm_config)
            response = llm.chat(messages=app_global_para['pure_messages'] + message)
            rsp = []
            for rsp in response:
                if rsp:
                    history[-1][1] = rsp[-1]['content']
                    yield history

            # Record the conversation history when the conversation succeeds
            app_global_para['pure_last_turn_msg_id'].append(len(app_global_para['pure_messages']))
            app_global_para['pure_messages'].extend(message)  # New user message
            app_global_para['pure_last_turn_msg_id'].append(len(app_global_para['pure_messages']))
            app_global_para['pure_messages'].extend(rsp)  # The response

This function is important because it defines how Qwen-Agent Tutorial: Tool-Enabled Agent Framework with MCP, RAG, and Multi-Modal Workflows implements the patterns covered in this chapter.

`qwen_server/workstation_server.py`

The pure_bot function in qwen_server/workstation_server.py handles a key part of this chapter's functionality:



def pure_bot(history):
    if not history:
        yield history
    else:
        history[-1][1] = ''
        message = [{'role': 'user', 'content': history[-1][0].text, 'name': 'pure_chat_user'}]
        try:
            llm = get_chat_model(llm_config)
            response = llm.chat(messages=app_global_para['pure_messages'] + message)
            rsp = []
            for rsp in response:
                if rsp:
                    history[-1][1] = rsp[-1]['content']
                    yield history

            # Record the conversation history when the conversation succeeds
            app_global_para['pure_last_turn_msg_id'].append(len(app_global_para['pure_messages']))
            app_global_para['pure_messages'].extend(message)  # New user message
            app_global_para['pure_last_turn_msg_id'].append(len(app_global_para['pure_messages']))
            app_global_para['pure_messages'].extend(rsp)  # The response

        except ModelServiceError as ex:
            history[-1][1] = str(ex)
            yield history
        except Exception as ex:
            raise ValueError(ex)


def keep_only_files_for_name(messages, name):
    new_messages = []

This function is important because it defines how Qwen-Agent Tutorial: Tool-Enabled Agent Framework with MCP, RAG, and Multi-Modal Workflows implements the patterns covered in this chapter.

How These Components Connect

flowchart TD
    A[layout_to_right]
    B[download_text]
    C[choose_plugin]
    D[pure_bot]
    E[keep_only_files_for_name]
    A --> B
    B --> C
    C --> D
    D --> E