langchain-toolstem

LangChain tools wrapping Toolstem MCP servers (Finance + SEC EDGAR) with x402 USDC micropayments — Python edition.

initialize and tools/list are free. Each tools/call costs $0.01 USDC on Base mainnet.

TypeScript sibling: langchain-toolstem

Install

pip install langchain-toolstem

With x402 payment support:

pip install 'langchain-toolstem[x402]'

Quick Start

Free Discovery (no wallet needed)

from langchain_toolstem import create_finance_tools, create_sec_tools

# List available tools — free, no payment required
finance_tools = await create_finance_tools()
sec_tools = await create_sec_tools()

for t in finance_tools + sec_tools:
    print(f"{t.name}: {t.description[:80]}")

Paid Tool Calls (with wallet)

from langchain_toolstem import create_finance_tools, create_x402_httpx_client

# Create a paying HTTP client (needs USDC on Base mainnet)
client = await create_x402_httpx_client("0xYOUR_PRIVATE_KEY")

# Tools automatically pay 0.01 USDC per call
tools = await create_finance_tools(http_client=client)
result = await tools[0].ainvoke({"symbol": "AAPL"})
print(result)

With LangGraph Agent

from langchain_openai import ChatOpenAI
from langgraph.prebuilt import create_react_agent

from langchain_toolstem import create_finance_tools, create_x402_httpx_client

client = await create_x402_httpx_client(os.environ["X402_PRIVATE_KEY"])
tools = await create_finance_tools(http_client=client)

agent = create_react_agent(ChatOpenAI(model="gpt-4o"), tools)
result = await agent.ainvoke({
    "messages": [{"role": "user", "content": "Analyze NVDA stock"}]
})

API Reference

create_finance_tools(**kwargs) -> list[StructuredTool]

Discover and return the 3 Finance tools.

create_sec_tools(**kwargs) -> list[StructuredTool]

Discover and return the 5 SEC EDGAR tools.

create_x402_httpx_client(private_key, *, max_payment_usd=1.0) -> httpx.AsyncClient

Create an httpx.AsyncClient that auto-pays x402 USDC micropayments on HTTP 402.

discover_toolstem_tools(url, **kwargs) -> list[StructuredTool]

Low-level: connect to any Toolstem MCP endpoint and return LangChain tools.

Common kwargs for all functions:

Network Details

Walletless Playground

Try the tools without a wallet at toolstem.com/playground — real, cached responses, no payment required.

Development

git clone https://github.com/toolstem/langchain-toolstem-python
cd langchain-toolstem-python
pip install -e '.[dev]'
pytest

Publishing to PyPI

This package uses PyPI Trusted Publishing (OIDC) — no API tokens needed.

One-time setup:

1. Go to pypi.org/manage/account/publishing
2. Add a new pending publisher:
   • PyPI project name: langchain-toolstem
   • Owner: toolstem
   • Repository: langchain-toolstem-python
   • Workflow: publish.yml
   • Environment: pypi
3. Tag a release: git tag v0.1.0 && git push origin v0.1.0
4. GitHub Actions will build and publish automatically.

License

MIT