Example code doesnt work

[mrifni]

My sample code

// 1. Configure MCP servers
    const config = {
      mcpServers: {
        playwright: { command: "npx", args: ["@playwright/mcp@latest"] },
      },
    };
    const client = MCPClient.fromDict(config);

    const llm = new ChatOpenAI({ model: "gpt-4o", temperature: 0 });
    const agent = new MCPAgent({ llm: llm, client: client, maxSteps: 30 });

    const result = await agent.run(`Hello world`, 30);
    console.log(`\nResult: ${result}`);

my package.json file

"@langchain/openai": "^0.5.15",
"langchain": "^0.3.27",
"openai": "^5.12.2",
"mcp-use": "^0.1.11",
"@playwright/mcp": "^0.0.33",
"@modelcontextprotocol/sdk": "^1.17.2",

[Pederzh]

Hey @mrifni thanks for reporting the issue!

The mcp-use package has @langchain/core@0.3.58 as a dependency
The any other project is pulling in @langchain/core@0.3.71 through its other dependencies (@langchain/openai, langfuse-langchain)
This creates type incompatibilities between the same interfaces from different versions.

It's solved in mcp-use version 0.1.17.
Can you try it?

[Crymzix]

@Pederzh I'm still experiencing the same error with these dependencies:

"@langchain/community": "^0.3.53",
"@langchain/core": "^0.3.72",
"@langchain/ollama": "^0.2.3",
"@langchain/openai": "^0.6.9",
"mcp-use": "^0.1.17"