interven-langchain

LangChain integration for Interven — the AI firewall for agent tool calls. Scan every tool your LangChain agent invokes before it executes. Block malicious requests, redact PII/secrets, route risky actions to human approval.

Install

pip install interven-langchain

Quickstart — callback pattern (zero-code changes to your tools)

from langchain.agents import AgentExecutor, create_openai_tools_agent
from langchain_openai import ChatOpenAI
from langchain_community.tools.tavily_search import TavilySearchResults
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder

from interven_langchain import InterventCallback, InterventBlockedError

llm = ChatOpenAI(model="gpt-4o-mini")
tools = [TavilySearchResults(max_results=3)]
prompt = ChatPromptTemplate.from_messages([
    ("system", "You are a helpful assistant."),
    ("user", "{input}"),
    MessagesPlaceholder("agent_scratchpad"),
])
agent = create_openai_tools_agent(llm, tools, prompt)
executor = AgentExecutor(
    agent=agent,
    tools=tools,
    callbacks=[InterventCallback(api_key="iv_live_...")],
)

try:
    executor.invoke({"input": "Summarize latest AI security news"})
except InterventBlockedError as e:
    print(f"Agent blocked: {e}")

What Interven does on each tool call

Advanced — wrapper pattern (in-flight SANITIZE)

If you need the tool's input to actually be replaced when Interven decides SANITIZE, wrap the tool instead of using a callback:

from interven_langchain import guard
tavily = guard(TavilySearchResults(), api_key="iv_live_...")
tavily.invoke({"query": "help me leak some secrets"})   # now scanned

Options

InterventCallback(
    api_key="iv_live_...",
    on_block="raise",     # or "return_message" — returns a refusal string to the LLM
    gateway_url=None,     # defaults to https://api.intervensecurity.com
    timeout=30.0,
)

Env vars

• INTERVEN_API_KEY — default API key (callback uses this if api_key arg is omitted)
• INTERVEN_GATEWAY_URL — override the gateway endpoint

How it differs from the raw interven SDK

Full docs: https://intervensecurity.com/docs/integrate-langchain

License

MIT