> For the complete documentation index, see [llms.txt](https://docs.otari.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.otari.ai/otari/for-integrators/chatgpt-subscription.md).

# Use with a ChatGPT subscription

A ChatGPT subscription is separate from the OpenAI Platform API and does not provide a standard API key. Otari can reach subscription-backed models only through a third-party Codex OAuth proxy that exposes an OpenAI-compatible API.

```
application -> Otari -> local OAuth proxy -> ChatGPT subscription
```

This is an unofficial integration. OpenAI may change the backend, subscription limits still apply, and a third-party proxy may create account or terms-of-service risk. Use an OpenAI Platform API key for production workloads.

## Prerequisites

* A local Otari deployment
* A ChatGPT Plus or Pro subscription
* A Codex OAuth proxy that serves an OpenAI-compatible API, such as [CLIProxyAPI](https://github.com/router-for-me/CLIProxyAPI)

Run the proxy on a private address and follow its authentication instructions. It holds your subscription session and should not be exposed publicly.

## Verify the proxy

Ask the proxy for its model catalog, including its downstream key if configured:

```bash
curl http://localhost:8317/v1/models \
  -H "Authorization: Bearer $CHATGPT_PROXY_KEY"
```

If it does not implement `/v1/models`, verify with a chat completion and declare its model IDs explicitly in Otari.

## Register it in Otari

Create a named OpenAI-compatible provider instance:

```yaml
providers:
  chatgpt:
    provider_type: openai-compatible
    api_base: "http://localhost:8317/v1"
    api_key: ${CHATGPT_PROXY_KEY}
    models:
      - gpt-5
```

Remove `api_key` when the proxy is intentionally keyless. The `models` list is needed only when the proxy has no working model-listing endpoint.

Models use the instance name, for example `chatgpt:gpt-5`. See [Named provider instances](/otari/for-operators/models.md#named-provider-instances).

## Pricing

A subscription has no per-token invoice. You can either:

* Leave the model unpriced and set `require_pricing: false`.
* Configure a counterfactual API price for analytics.

```yaml
pricing:
  chatgpt:gpt-5:
    input_price_per_million: 1.25
    output_price_per_million: 10.00
```

Configured pricing also drives budget enforcement. A counterfactual price can therefore exhaust a real Otari budget even though the subscription charged no per-request fee.

## Route a request

```python
from otari import OtariClient

client = OtariClient(api_base="http://localhost:8000", api_key="tk-...")
response = client.completion(
    model="chatgpt:gpt-5",
    messages=[{"role": "user", "content": "Say hello in five words."}],
)
print(response.choices[0].message.content)
```

Provider routing, API-key access, usage logging, and configured budgets work as they do for any other named instance.

## Caveats

* The proxy may break when its upstream backend changes.
* Subscription usage caps remain in force.
* Keep the proxy and its OAuth session private.
* Model IDs and capabilities come from the proxy, not from Otari.
* API pricing attached to the instance is an estimate, not the subscription's actual charge.

For the supported API-key path, use the [OpenAI provider guide](/otari/for-operators/openai.md).


---

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