codex-auth-helper turns an existing local Codex auth session into a pydantic-ai model.

It reads ~/.codex/auth.json, refreshes access tokens when needed, builds a custom AsyncOpenAI client for the Codex Responses endpoint, and returns a ready-to-use CodexResponsesModel.

• 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

The helper enforces two backend-specific behaviors for you:

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

• It does not log you into Codex
• It does not create ~/.codex/auth.json
• It does not currently support pydantic_ai.models.openai.OpenAIChatModel or Chat Completions flows
• OpenAIChatModel support is planned for a later release
• It does not replace pydantic-ai; it only provides a model/client factory

uv pip install codex-auth-helper

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

~/.codex/auth.json

If you have not logged in yet:

codex login

from codex_auth_helper import create_codex_responses_model
from pydantic_ai import Agent

model = create_codex_responses_model("gpt-5")
agent = Agent(model, instructions="You are a helpful coding assistant.")

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

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", config=config)

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",
    settings={
        "openai_reasoning_summary": "concise",
    },
)

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.

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

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.

This package is intentionally small and focused:

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