LangChain Tax Compliance

Add sales tax calculation as a native LangChain tool. Your agents resolve tax obligations before invoicing — no guessing, no manual lookups, no compliance gaps.

INSTALL

3-step setup

Define the LangChain tool

Wrap the AgentTax SDK in a @tool-decorated function. LangChain handles the rest — the agent will call it automatically when it needs tax information.

from langchain.tools import tool
from agenttax import AgentTaxClient

client = AgentTaxClient(api_key="atx_live_...")

@tool
def calculate_sales_tax(
    amount: float,
    buyer_state: str,
    transaction_type: str,
    counterparty_id: str,
    is_b2b: bool = False,
) -> dict:
    """Calculate US sales tax for an agent transaction.

    Args:
        amount: Transaction amount in USD
        buyer_state: Two-letter state code (e.g. 'CA', 'TX')
        transaction_type: Type of service ('saas', 'compute', 'consulting', etc.)
        counterparty_id: Unique ID of the buyer agent
        is_b2b: True if selling to another business

    Returns:
        dict with taxable, total_tax, combined_rate, confidence
    """
    return client.calculate(
        role="seller",
        amount=amount,
        buyer_state=buyer_state,
        transaction_type=transaction_type,
        counterparty_id=counterparty_id,
        is_b2b=is_b2b,
    )

Add to your agent

Pass it alongside your other tools. The agent decides when to call it based on context.

from langchain.agents import AgentExecutor, create_openai_tools_agent
from langchain_openai import ChatOpenAI
from langchain.tools import tool

# Add the tool to your agent
tools = [calculate_sales_tax]

llm = ChatOpenAI(model="gpt-4o")
agent = create_openai_tools_agent(llm, tools, prompt)
executor = AgentExecutor(agent=agent, tools=tools)

# Agent now resolves tax before invoicing
result = executor.invoke({
    "input": "I'm billing agent-buyer-42 $1,500 for compute work in Texas. What's the tax?"
})
# Agent calls calculate_sales_tax(1500, "TX", "compute", "agent-buyer-42")
# → taxable: True, total_tax: 75.00, combined_rate: 5%, confidence: high

Response shape

{
  "taxable": true,
  "total_tax": 75.00,
  "combined_rate": 0.05,
  "state_tax": 75.00,
  "local_tax": 0.00,
  "buyer_state": "TX",
  "transaction_type": "compute",
  "work_type": "compute",
  "classification_basis": "digital_service",
  "confidence": { "score": 95, "level": "high" },
  "advisories": ["TX §151.351: 80% of digital services taxable (20% statutory exemption)"],
  "transaction_id": "txn_abc123"
}

What the tool covers

Other integrations