> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ai-stats.phaseo.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Codex

> Use the AI Stats Gateway as a custom provider for Codex CLI.

Codex CLI supports custom model providers through `~/.codex/config.toml`, so you can route requests to AI Stats without changing your local workflow.

## Prerequisites

* An AI Stats API key.
* Codex CLI installed locally.

## 1) Set your API key

```bash theme={null}
export AI_STATS_API_KEY="your_ai_stats_api_key"
```

```powershell theme={null}
$env:AI_STATS_API_KEY = "your_ai_stats_api_key"
```

## 2) Configure Codex to use AI Stats

Create or update `~/.codex/config.toml`:

```toml theme={null}
model = "openai/gpt-5-3-codex-2026-02-05"
model_provider = "ai_stats"

[model_providers.ai_stats]
name = "AI Stats"
base_url = "https://api.phaseo.app/v1"
env_key = "AI_STATS_API_KEY"
wire_api = "responses"
```

## 3) Start Codex

```bash theme={null}
codex
```

## Verification

* Confirm your model id exists in [Models](../../api-reference/endpoint/models.mdx) before launching.
* Use [Responses](../../api-reference/endpoint/responses.mdx) for the default Codex-style flow.
* If needed for compatibility, switch `wire_api` to `chat` and use [Chat Completions](../../api-reference/endpoint/chat-completions.mdx).

## Troubleshooting

* `401 Unauthorized`: check that `AI_STATS_API_KEY` is set in the same shell running `codex`.
* `model_not_found`: fetch a current id from [Models](../../api-reference/endpoint/models.mdx) and update `model`.
* Provider-specific issues: follow [Routing and fallbacks](../routing-and-fallbacks.mdx) for failover behavior.