FurlPay for LangChain

Give your LangChain agents a wallet. This package exposes the FurlPay API as a set of typed LangChain tools — so an agent can check balances, create checkouts, move stablecoins, place investment orders, and pay for x402-protected APIs within a spending budget.

FurlPay is the open-source financial OS for the agentic internet: stablecoin payments + the first Solana-native x402 facilitator. This is the LangChain binding for it.

Maintained by FurlPay · MIT licensed.

Install

pip install furlpay-langchain

Quickstart

from furlpay_langchain import get_furlpay_tools

tools = get_furlpay_tools()          # reads FURLPAY_API_KEY from the environment
llm_with_tools = llm.bind_tools(tools)

Zero-config: with no FURLPAY_API_KEY set, every tool runs in demo mode — reads return deterministic sample data and writes simulate without touching the network. Wire up your agent and watch the tool calls before you ever create an account. Set the key to go live against https://api.furlpay.com/v1.

export FURLPAY_API_KEY=fp_live_sk_...          # optional; omit for demo mode
export FURLPAY_API_BASE=https://sandbox.api.furlpay.com/v1   # optional sandbox

Tools

⚡ furlpay_pay_for_resource is the headline: it lets an agent buy metered data or API access over x402 — the payment primitive API keys can't express — while set_agent_budget keeps it from overspending.

Full agent example

from langchain.agents import AgentExecutor, create_tool_calling_agent
from langchain_anthropic import ChatAnthropic
from langchain_core.prompts import ChatPromptTemplate
from furlpay_langchain import get_furlpay_tools

tools = get_furlpay_tools()
llm = ChatAnthropic(model="claude-sonnet-5", temperature=0)
prompt = ChatPromptTemplate.from_messages([
    ("system", "You are a treasury agent with a FurlPay wallet."),
    ("human", "{input}"),
    ("placeholder", "{agent_scratchpad}"),
])
executor = AgentExecutor(agent=create_tool_calling_agent(llm, tools, prompt), tools=tools)
executor.invoke({"input": "Buy $25 of VOO and cap my x402 budget at $50/day."})

A runnable version is in examples/agent.py:

pip install "furlpay-langchain[examples]"
python examples/agent.py

Use an explicit client

from furlpay_langchain import FurlPayClient, get_furlpay_tools

client = FurlPayClient(api_key="fp_live_sk_...", base_url="https://api.furlpay.com/v1")
tools = get_furlpay_tools(client)

Also works with LangGraph and anything else that accepts BaseTool — the tools are standard StructuredTools with Pydantic argument schemas.

Test

pip install "furlpay-langchain[dev]"
python -m pytest tests -q        # or, no pytest:  python tests/test_tools.py

The suite runs in demo mode and asserts the tool contract: every tool is a well-formed StructuredTool, names are unique and namespaced, each is invocable and returns serialisable output, and the x402 budget guard refuses to overspend.

Scope

This package orchestrates FurlPay's public API into LangChain tools. It doesn't custody funds or sign transactions itself — wallets, MPC custody, brokerage (via Alpaca), and x402 settlement all happen in the FurlPay API. Point it at your own FurlPay account and it operates on your data.

License

MIT