codex-auth-helper 0.9.2

Codex auth helpers for pydantic-ai OpenAI Responses models.

codex-auth-helper

codex-auth-helper turns an existing local Codex auth session into either:

• a pydantic-ai Responses model
• a LangChain ChatOpenAI model pinned to the OpenAI Responses API

It reads ~/.codex/auth.json, refreshes access tokens when needed, builds Codex-specific OpenAI clients for the Responses endpoint, and returns either a ready-to-use CodexResponsesModel or a LangChain chat model.

What It Does

• Reads tokens from ~/.codex/auth.json
• Derives ChatGPT-Account-Id from the auth file or token claims
• Refreshes expired access tokens with https://auth.openai.com/oauth/token
• Writes refreshed tokens back to the auth file
• Builds an OpenAI-compatible client pointed at https://chatgpt.com/backend-api/codex
• Returns a pydantic-ai responses model that already applies the Codex backend requirements
• Returns a LangChain ChatOpenAI model configured for the Responses API

The helper enforces two backend-specific behaviors for you:

• openai_store=False
• streamed responses even when pydantic-ai calls the non-streamed request() path

What It Does Not Do

• It does not log you into Codex
• It does not create ~/.codex/auth.json
• It does not provide generic Chat Completions wiring
• It does not replace pydantic-ai; it only provides a model/client factory

Install

uv add codex-auth-helper

pip install codex-auth-helper

For LangChain usage:

uv add "codex-auth-helper[langchain]"

pip install "codex-auth-helper[langchain]"

You also need an existing Codex auth session on the same machine:

~/.codex/auth.json

If you have not logged in yet:

codex login

Quick Start

from codex_auth_helper import create_codex_responses_model
from pydantic_ai import Agent

model = create_codex_responses_model(
    "gpt-5.4",
    instructions="You are a helpful coding assistant.",
)
agent = Agent(model)

result = agent.run_sync("Naber")
print(result.output)

LangChain Quick Start

from codex_auth_helper import create_codex_chat_openai
from langchain.agents import create_agent

graph = create_agent(
    model=create_codex_chat_openai(
        "gpt-5.4",
        instructions="You are a helpful coding assistant.",
    ),
    tools=[],
    name="codex-graph",
)

The LangChain helper returns langchain_openai.ChatOpenAI configured to:

• use the Codex Responses endpoint
• reuse local Codex auth state
• keep use_responses_api=True
• default to output_version="responses/v1"
• require instructions= and pass it through to the Responses request

instructions is mandatory for create_codex_chat_openai(...). The helper does not provide an implicit system prompt for the LangChain path; callers must pass the behavior they want explicitly.

The same rule applies to create_codex_responses_model(...) on the Pydantic path. Pass the Codex system behavior to the helper directly instead of relying on a separate agent-level instruction just to seed the model.

Custom Auth Path

If you want to read a different auth file, pass a custom config:

from pathlib import Path

from codex_auth_helper import CodexAuthConfig, create_codex_responses_model

config = CodexAuthConfig(auth_path=Path("/tmp/codex-auth.json"))
model = create_codex_responses_model(
    "gpt-5.4",
    config=config,
    instructions="You are a helpful coding assistant.",
)

Passing Extra OpenAI Responses Settings

Additional OpenAIResponsesModelSettings can still be passed through. The helper keeps openai_store=False unless you explicitly override the model after construction.

from codex_auth_helper import create_codex_responses_model

model = create_codex_responses_model(
    "gpt-5.4",
    instructions="You are a helpful coding assistant.",
    settings={
        "openai_reasoning_summary": "concise",
    },
)

Lower-Level Client Factory

If you only want the authenticated OpenAI client, use create_codex_async_openai(...):

from codex_auth_helper import create_codex_async_openai

client = create_codex_async_openai()

This returns CodexAsyncOpenAI, a subclass of openai.AsyncOpenAI.

If you need the sync OpenAI client, use create_codex_openai(...).

Public API

from codex_auth_helper import (
    CodexAsyncOpenAI,
    CodexAuthConfig,
    CodexAuthState,
    CodexOpenAI,
    CodexAuthStore,
    CodexResponsesModel,
    CodexTokenManager,
    create_codex_async_openai,
    create_codex_chat_openai,
    create_codex_openai,
    create_codex_responses_model,
)

Errors

Typical failure modes:

• Codex auth file was not found ... The machine is not logged into Codex yet.
• Codex auth file ... does not contain valid JSON The auth file is corrupt or partially written.
• ModelHTTPError ... Store must be set to false Means you are not using the helper-backed model instance.
• ModelHTTPError ... Stream must be set to true Means you are not using CodexResponsesModel.

Package Notes

This package is intentionally small and focused:

• auth file parsing
• token refresh
• Codex-specific OpenAI client wiring
• pydantic-ai responses model factory
• LangChain Responses-model factory

Documentation

• Helpers Overview
• API Reference