OpenAI middleware integration

model ModerationModel default: omni-moderation-latest

OpenAI moderation model to use. Options: 'omni-moderation-latest', 'omni-moderation-2024-09-26', 'text-moderation-latest', 'text-moderation-stable'

check_input bool default: True

Whether to check user input messages before the model is called

check_output bool default: True

Whether to check model output messages after the model is called

check_tool_results bool default: False

Whether to check tool result messages before the model is called

exit_behavior string default: end

How to handle violations when content is flagged. Options:

• 'end' - End agent execution immediately with a violation message
• 'error' - Raise OpenAIModerationError exception
• 'replace' - Replace the flagged content with the violation message and continue

violation_message str | None

Custom template for violation messages. Supports template variables:

• {categories} - Comma-separated list of flagged categories
• {category_scores} - JSON string of category scores
• {original_content} - The original flagged content

Default: "I'm sorry, but I can't comply with that request. It was flagged for {categories}."

client OpenAI | None

Optional pre-configured OpenAI client to reuse. If not provided, a new client will be created.

async_client AsyncOpenAI | None

Optional pre-configured AsyncOpenAI client to reuse. If not provided, a new async client will be created.

The middleware integrates OpenAI's moderation endpoint to check content at different stages:

Moderation stages:

• check_input - User messages before model call
• check_output - AI messages after model call
• check_tool_results - Tool outputs before model call

Exit behaviors:

• 'end' (default) - Stop execution with violation message
• 'error' - Raise exception for application handling
• 'replace' - Replace flagged content and continue

from langchain_openai import ChatOpenAI
from langchain_openai.middleware import OpenAIModerationMiddleware
from langchain.agents import create_agent


# Basic moderation
agent = create_agent(
    model=ChatOpenAI(model="gpt-5.5"),
    tools=[search_tool, customer_data_tool],
    middleware=[
        OpenAIModerationMiddleware(
            model="omni-moderation-latest",
            check_input=True,
            check_output=True,
        ),
    ],
)

# Strict moderation with custom message
agent_strict = create_agent(
    model=ChatOpenAI(model="gpt-5.5"),
    tools=[search_tool, customer_data_tool],
    middleware=[
        OpenAIModerationMiddleware(
            model="omni-moderation-latest",
            check_input=True,
            check_output=True,
            check_tool_results=True,
            exit_behavior="error",
            violation_message=(
                "Content policy violation detected: {categories}. "
                "Please rephrase your request."
            ),
        ),
    ],
)

# Moderation with replacement behavior
agent_replace = create_agent(
    model=ChatOpenAI(model="gpt-5.5"),
    tools=[search_tool],
    middleware=[
        OpenAIModerationMiddleware(
            check_input=True,
            exit_behavior="replace",
            violation_message="[Content removed due to safety policies]",
        ),
    ],
)