FiGuard Python SDK

Pre-flight spend authorization for AI agents. Stop your agent from overspending before it happens.

Install

pip install figuard

# Async support (LangChain, CrewAI, OpenAI Agents):
pip install figuard[async]

Requires Python 3.11+.

Quickstart

from figuard import FiGuardClient, FiGuardDeniedException

client = FiGuardClient(api_key="ab_live_...")

# 1. Create a budget for your user's session
budget = client.create_budget(
    user_id="user_123",
    total_limit=500.00,
    expires_at="2024-12-31T23:59:59Z",
)

# 2. Pre-authorize every spend before it happens
try:
    result = client.authorize(
        session_token=budget.session_token,
        agent_id="agent_flight_booker",
        action_type="PURCHASE",
        description="NYC to LAX flight",
        requested_amount=299.00,
        idempotency_key="txn-abc-001",  # required — use a stable unique key
    ).raise_if_denied()

    # 3. Execute the real transaction, then confirm
    external_tx_id = payment_processor.charge(299.00)
    client.confirm_event(result.event_id, confirmed_amount=299.00,
                         external_transaction_id=external_tx_id)

except FiGuardDeniedException as e:
    print(f"Spend denied: {e.denial_reason}")
    # e.g. INSUFFICIENT_FUNDS, BUDGET_PAUSED, ANOMALY_DETECTED

Async (LangChain / CrewAI / OpenAI Agents)

import asyncio
from figuard import AsyncFiGuardClient

async def run_agent():
    async with AsyncFiGuardClient(api_key="ab_live_...") as client:
        budget = await client.create_budget(
            user_id="user_123",
            total_limit=500.00,
            expires_at="2024-12-31T23:59:59Z",
        )

        result = await client.authorize(
            session_token=budget.session_token,
            agent_id="langchain_agent",
            action_type="PURCHASE",
            description="Hotel booking",
            requested_amount=189.00,
            idempotency_key="hotel-booking-001",
        )

        if result.is_authorized:
            await client.confirm_event(result.event_id, confirmed_amount=189.00)

Allocation-based budgets

Allocations let you ring-fence spend by category and enforce item-type rules:

budget = client.create_budget(
    user_id="user_123",
    total_limit=500.00,
    expires_at="2024-12-31T23:59:59Z",
    allocations=[
        {
            "category": "flights",
            "allowedCategories": ["flight", "airline"],
            "limit": 300.00,
            "enforcementMode": "STRICT",
            "forbiddenItemTypes": ["gift_card", "upgrade"],
        },
        {
            "category": "hotels",
            "allowedCategories": ["hotel", "accommodation"],
            "limit": 200.00,
            "enforcementMode": "CATEGORY_CONSTRAINED",
        },
    ],
)

# claimedCategory must match one of allowedCategories
result = client.authorize(
    session_token=budget.session_token,
    agent_id="travel_agent",
    action_type="PURCHASE",
    description="Flight to NYC",
    requested_amount=250.00,
    idempotency_key="flight-nyc-001",
    claimed_category="flight",
    claimed_item_type="economy_ticket",
)

Payment lifecycle

# Authorize reserves funds — money has not moved yet
result = client.authorize(...).raise_if_denied()

# Confirm when payment succeeds — finalizes the spend
client.confirm_event(result.event_id, confirmed_amount=249.00)

# Fail when the payment processor declines — releases the reservation
client.fail_event(result.event_id, reason="PAYMENT_DECLINED")

# Void if the action is cancelled before payment
client.void_event(result.event_id, reason="USER_CANCELLED")

Anomaly detection

Enable per-budget anomaly detection to auto-pause budgets when a single request is statistically unusual:

budget = client.create_budget(
    user_id="user_123",
    total_limit=2000.00,
    expires_at="2024-12-31T23:59:59Z",
    anomaly_detection_enabled=True,
    # optional: dedicated URL for anomaly alerts
    # anomaly_alert_webhook_url="https://your-service.com/alerts",
)

When a request exceeds mean × multiplier (default 3×) and at least 5 prior transactions exist, the budget is auto-paused and an ANOMALY_DETECTED webhook fires. Resume after review:

budget = client.resume_budget(
    budget_id,
    override_reason="Reviewed — legitimate bulk purchase",
    override_by="ops-team",
)

Error handling

from figuard import (
    FiGuardDeniedException,   # decision == DENIED (not an HTTP error)
    FiGuardApiError,          # 4xx / 5xx from the API
    FiGuardConnectionError,   # network failure after all retries
)

try:
    result = client.authorize(...).raise_if_denied()
except FiGuardDeniedException as e:
    print(e.denial_reason)    # e.g. "INSUFFICIENT_FUNDS"
    print(e.denial_message)   # human-readable explanation
    # if denial_reason == "ENTITY_ALREADY_AUTHORIZED":
    #   e.original_event_id   # UUID of the existing event
except FiGuardApiError as e:
    print(e.status_code, e.message)
except FiGuardConnectionError as e:
    print("Network failure:", e)

The SDK automatically retries 5xx responses up to 3 times with exponential backoff (1s, 2s, 4s). 4xx errors are never retried.

Ledger and reporting

# Paginated spend history
page = client.get_ledger(budget_id, page=0, size=20, decision="CONFIRMED")
for event in page.events:
    print(event.id, event.decision, event.confirmed_amount)

# Causal spend tree (which agent triggered which spend)
tree = client.get_spend_tree(budget_id)
for root in tree.roots:
    print(root.event.agent_id, len(root.children), "child events")

Configuration

client = FiGuardClient(
    api_key="ab_live_...",
    base_url="https://api.figuard.io",  # override for self-hosted
    timeout=30,                          # per-request timeout in seconds
)

Security notes

• The raw session_token is returned once on create_budget() and never again. Store it securely — treat it like a password.
• The SDK logs only the first 8 characters of the session token. The full token never appears in logs.
• idempotency_key is required on every authorize() call. Use a stable unique key per logical spend intent so retries are safe.

Framework integrations

Each integration is an optional extra. Install only what you need.

LangChain / LangGraph

pip install figuard[langchain]

from figuard.integrations.langchain import FiGuardCallbackHandler, FiGuardToolGuard

# Option A — callback handler: guards every tool in an AgentExecutor
executor = AgentExecutor(
    agent=agent,
    tools=tools,
    handle_tool_error=True,   # required — sends denial to the LLM
    callbacks=[FiGuardCallbackHandler(
        client=client,
        session_token=budget.session_token,
        tool_category_map={"book_flight": "flight", "book_hotel": "hotel"},
        ignore_tools={"search_web"},   # skip authorization for read-only tools
    )],
)

# Option B — tool guard: wraps a single tool in-place, hard enforcement
FiGuardToolGuard(
    tool=book_flight_tool,
    client=client,
    session_token=budget.session_token,
    category="flight",
    amount_key="price",
)

FiGuardCallbackHandler raises ToolException on denial — the LLM receives the denial reason and can try an alternative. FiGuardToolGuard patches tool._run directly so the tool never runs regardless of AgentExecutor configuration.

CrewAI

pip install figuard[crewai]

from figuard.integrations.crewai import FiGuardCrewGuard

FiGuardCrewGuard(
    tool=book_flight_tool,
    client=client,
    session_token=budget.session_token,
    category="flight",
    amount_key="price",
)
travel_agent = Agent(role="Travel Coordinator", tools=[book_flight_tool])

OpenAI Agents SDK

pip install figuard[openai-agents]

from agents import function_tool
from figuard.integrations.openai_agents import guarded_function_tool

@function_tool
@guarded_function_tool(
    client=client,
    session_token=budget.session_token,
    category="flight",
    amount_key="price",
)
def book_flight(destination: str, price: float) -> str:
    """Book a flight to the specified destination."""
    ...

Apply @guarded_function_tool as the inner decorator (before @function_tool) so FiGuard wraps the raw function and has access to all kwargs.

OpenAI Function Calling

pip install figuard[openai]

import json
from figuard.integrations.openai import guarded_openai_function

@guarded_openai_function(
    client=client,
    session_token=budget.session_token,
    category="flight",
)
def book_flight(destination: str, amount: float) -> str:
    ...

# Dispatch in your tool call loop:
for tool_call in response.choices[0].message.tool_calls:
    if tool_call.function.name == "book_flight":
        result = book_flight(**json.loads(tool_call.function.arguments))

Anthropic Tool Use

pip install figuard[anthropic]

from figuard.integrations.anthropic import guarded_anthropic_tool

@guarded_anthropic_tool(
    client=client,
    session_token=budget.session_token,
    category="flight",
)
def book_flight(destination: str, amount: float) -> str:
    ...

# Dispatch in your tool use loop (Anthropic passes block.input as a dict):
for block in response.content:
    if block.type == "tool_use" and block.name == "book_flight":
        result = book_flight(**block.input)

Denial handling across all integrations

When a tool call is denied, each integration handles it differently:

The denial string format: "FiGuard DENIED: <code> — <message>", e.g.:

FiGuard DENIED: INSUFFICIENT_FUNDS — flight allocation has $0.00 remaining