LangChain Integration

You can use the WDK MCP Toolkit as a tool provider for LangChain agents in both Python and TypeScript. LangChain's MultiServerMCPClient spawns the MCP server as a subprocess and converts WDK tools into LangChain-compatible tools, giving your agent access to wallet operations, pricing, swaps, bridges, lending, and more.

This integration uses the serve CLI command, which starts a fully configured MCP server on stdio with no server script required.

The serve Command

Complete the pinned source setup first. From that checkout, serve starts the MCP server without a custom server script:

node bin/index.js serve

Configure a trusted secret-manager command to enable wallet operations. Replace the placeholder with your own executable that prints only the mnemonic to stdout, and authenticate the secret manager before starting the agent. The command must work without interactive input. See seed sources, precedence, and startup behavior.

# With wallet operations
WDK_SEED_COMMAND="/absolute/path/to/trusted-seed-loader" node bin/index.js serve

# Pricing-only mode (no seed sources configured)
unset WDK_SEED WDK_SEED_COMMAND WDK_SEED_FILE
node bin/index.js serve

Default Chains

By default, serve enables three chains: Ethereum, Arbitrum, and Bitcoin. For each enabled chain it dynamically imports the required wallet package and skips any that aren't installed. You can change the enabled set with the WDK_CHAINS environment variable.

Built-in Registry

The command has built-in definitions for 13 chains and 4 protocol modules. When a chain is enabled and its configured package is installed, the wallet is registered automatically. Protocol modules are also auto-registered when their packages are installed and at least one of their target chains is enabled.

Use the package's CHAINS export as the complete accepted-identifier registry for the source checkout; see Built-in Chain Identifiers.

The pinned serve source imports @tetherto/wdk-wallet-sol for Solana. To use the installed @tetherto/wdk-wallet-solana package, set chains.solana.module to "@tetherto/wdk-wallet-solana" in a custom config file, supply its wallet configuration, and enable solana through enabledChains (or WDK_CHAINS when enabledChains is omitted).

Quick Start

Replace /absolute/path/wdk-mcp-toolkit in both examples with your source checkout path and /absolute/path/to/trusted-seed-loader with your secret-manager executable. WDK does not provide the loader. Authenticate it first, ensure it runs without interactive input in the server's environment, and unset any inherited WDK_SEED so it cannot override the command source.

pip install langchain-mcp-adapters langgraph langchain-openai

import asyncio
from langchain_mcp_adapters.client import MultiServerMCPClient
from langgraph.prebuilt import create_react_agent
from langchain_openai import ChatOpenAI

async def main():
    client = MultiServerMCPClient({
        "wdk": {
            "transport": "stdio",
            "command": "node",
            "args": ["/absolute/path/wdk-mcp-toolkit/bin/index.js", "serve"],
            "env": {
                "WDK_SEED_COMMAND": "/absolute/path/to/trusted-seed-loader",
                "WDK_MCP_ELICITATION": "false",
            },
        }
    })

    tools = await client.get_tools()
    agent = create_react_agent(ChatOpenAI(model="gpt-4o"), tools)

    result = await agent.ainvoke({
        "messages": [{"role": "user", "content": "What is my Ethereum address?"}]
    })
    print(result["messages"][-1].content)

    await client.close()

asyncio.run(main())

export OPENAI_API_KEY="sk-..."
python agent.py

Configuration

Environment Variables

Control serve behavior through environment variables. The three seed sources are optional individually and are checked in the order shown. A nonempty resolved seed is required for wallet tools; see seed resolution and failure behavior.

Custom Config File

For chains or protocols not in the built-in defaults, create a wdk.config.json and pass its path via WDK_CONFIG:

WDK_CONFIG=./wdk.config.json WDK_SEED_COMMAND="/absolute/path/to/trusted-seed-loader" node bin/index.js serve

{
  "chains": {
    "zksync": {
      "module": "@myorg/wdk-wallet-zksync",
      "config": { "provider": "https://mainnet.era.zksync.io" }
    },
    "ethereum": {
      "config": { "provider": "https://my-private-rpc.com" }
    }
  },
  "protocols": [
    {
      "module": "@myorg/wdk-protocol-swap-custom",
      "label": "custom-swap",
      "type": "swap",
      "chains": ["zksync"]
    }
  ],
  "enabledChains": ["ethereum", "zksync", "bitcoin"]
}

LLM Provider Support

Both the Python and TypeScript examples support OpenAI and Anthropic. Set the corresponding environment variable and install the matching package:

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