聊聊langchain4j的MCP

McpTransport transport = new StdioMcpTransport.Builder()
    .command(List.of("/usr/bin/npm", "exec", "@modelcontextprotocol/server-everything@0.6.2"))
    .logEvents(true) // only if you want to see the traffic in the log
    .build();

McpTransport transport = new HttpMcpTransport.Builder()
    .sseUrl("http://localhost:3001/sse")
    .logRequests(true) // if you want to see the traffic in the log
    .logResponses(true)
    .build();

McpClient mcpClient = new DefaultMcpClient.Builder()
    .transport(transport)
    .logMessageHandler(new MyLogMessageHandler())
    .build();

ToolProvider toolProvider = McpToolProvider.builder()
    .mcpClients(List.of(mcpClient))
    .build();

Bot bot = AiServices.builder(Bot.class)
    .chatLanguageModel(model)
    .toolProvider(toolProvider)
    .build();

public static void main(String[] args) throws Exception {

    ChatLanguageModel model = OpenAiChatModel.builder()
        .apiKey(System.getenv("OPENAI_API_KEY"))
        .modelName("gpt-4o-mini")
        .logRequests(true)
        .logResponses(true)
        .build();

    McpTransport transport = new StdioMcpTransport.Builder()
        .command(List.of("/usr/local/bin/docker", "run", "-e", "GITHUB_PERSONAL_ACCESS_TOKEN", "-i", "mcp/github"))
        .logEvents(true)
        .build();

    McpClient mcpClient = new DefaultMcpClient.Builder()
        .transport(transport)
        .build();

    ToolProvider toolProvider = McpToolProvider.builder()
        .mcpClients(List.of(mcpClient))
        .build();

    Bot bot = AiServices.builder(Bot.class)
        .chatLanguageModel(model)
        .toolProvider(toolProvider)
        .build();

    try {
        String response = bot.chat("Summarize the last 3 commits of the LangChain4j GitHub repository");
        System.out.println("RESPONSE: " + response);
    } finally {
        mcpClient.close();
    }
}

Here are the summaries of the last three commits in the LangChain4j GitHub repository:

1. **Commit [36951f9](https://github.com/langchain4j/langchain4j/commit/36951f9649c1beacd8b9fc2d910a2e23223e0d93)** (Date: 2025-02-05)
   - **Author:** Dmytro Liubarskyi
   - **Message:** Updated to `upload-pages-artifact@v3`.
   - **Details:** This commit updates the GitHub Action used for uploading pages artifacts to version 3.

2. **Commit [6fcd19f](https://github.com/langchain4j/langchain4j/commit/6fcd19f50c8393729a0878d6125b0bb1967ac055)** (Date: 2025-02-05)
   - **Author:** Dmytro Liubarskyi
   - **Message:** Updated to `checkout@v4`, `deploy-pages@v4`, and `upload-pages-artifact@v4`.
   - **Details:** This commit updates multiple GitHub Actions to their version 4.

3. **Commit [2e74049](https://github.com/langchain4j/langchain4j/commit/2e740495d2aa0f16ef1c05cfcc76f91aef6f6599)** (Date: 2025-02-05)
   - **Author:** Dmytro Liubarskyi
   - **Message:** Updated to `setup-node@v4` and `configure-pages@v4`.
   - **Details:** This commit updates the `setup-node` and `configure-pages` GitHub Actions to version 4.

All commits were made by the same author, Dmytro Liubarskyi, on the same day, focusing on updating various GitHub Actions to newer versions.

@FunctionalInterface
public interface ToolProvider {

    /**
     * Provides tools for the request to the LLM.
     *
     * @param request {@link ToolProviderRequest} contains {@link UserMessage} and chat memory id (see {@link MemoryId}).
     * @return {@link ToolProviderResult} contains tools that should be included in the request to the LLM.
     */
    ToolProviderResult provideTools(ToolProviderRequest request);
}

public class McpToolProvider implements ToolProvider {

    private final List<McpClient> mcpClients;
    private final boolean failIfOneServerFails;
    private static final Logger log = LoggerFactory.getLogger(McpToolProvider.class);

    private McpToolProvider(Builder builder) {
        this.mcpClients = new ArrayList<>(builder.mcpClients);
        this.failIfOneServerFails = Utils.getOrDefault(builder.failIfOneServerFails, false);
    }

    @Override
    public ToolProviderResult provideTools(final ToolProviderRequest request) {
        ToolProviderResult.Builder builder = ToolProviderResult.builder();
        for (McpClient mcpClient : mcpClients) {
            try {
                List<ToolSpecification> toolSpecifications = mcpClient.listTools();
                for (ToolSpecification toolSpecification : toolSpecifications) {
                    builder.add(
                            toolSpecification, (executionRequest, memoryId) -> mcpClient.executeTool(executionRequest));
                }
            } catch (Exception e) {
                if (failIfOneServerFails) {
                    throw new RuntimeException("Failed to retrieve tools from MCP server", e);
                } else {
                    log.warn("Failed to retrieve tools from MCP server", e);
                }
            }
        }
        return builder.build();
    }

    //......
}