**TL;DR:** The OpenAI integration ships in langchain-openai. Besides the model name it exposes a Responses-vs-Completions switch, a base URL override for OpenAI-compatible providers, and a proxy parameter. Never paste a real key into code or chat. - For streaming token usage metadata from OpenAI, you must opt in on the integration; usage is not returned in streaming chunks by default.

## The fix

**TL;DR:** The OpenAI integration ships in langchain-openai. Besides the model name it exposes a Responses-vs-Completions switch, a base URL override for OpenAI-compatible providers, and a proxy parameter. Never paste a real key into code or chat. - For streaming token usage metadata from OpenAI, you must opt in on the integration; usage is not returned in streaming chunks by default.

## The fix

1. `use_responses_api` - picks the OpenAI Responses API vs the Chat Completions API.

2. `base_url` - point at an OpenAI-compatible endpoint (Together, vLLM, and similar) while keeping `model_provider="openai"` semantics. Provider-specific fields from routers may not be preserved through this path.

3. `openai_proxy` - HTTP proxy for deployments that need one.

4. `max_retries` / `timeout` - resilience (see the retry skill). Defaults: up to 6 retries on 429/5xx/network errors.

5. OpenRouter: `ChatOpenRouter` from `langchain-openrouter`

6. LiteLLM: `ChatLiteLLM` / `ChatLiteLLMRouter` from `langchain-litellm` Do not point ChatOpenAI at a router's base URL and expect router-specific fields to survive. The docs call this out explicitly.

7. The key comes from OPENAI_API_KEY in the environment. Never paste a real key into code or chat.

8. For streaming token usage metadata from OpenAI, you must opt in on the integration; usage is not returned in streaming chunks by default.

## When to use this

- This covers exactly what the title says: ChatOpenAI integration.
- You are setting this up for the first time, or auditing an existing setup.
- You want the key gotchas in one place before you start.

## When not to use this

- You are doing a different workflow with ChatOpenAI; these steps are specific to the title above.
- You need the full reference docs; this is the short path, not the manual.

## Compatibility

- Mentions 5.5 in the original; behavior may differ on much older or newer releases.

---

## Vectle citations

- Exact version: <https://vectle.com/skills/skl_1xnNeFDfmh-FsKTQe7pdSA/versions/skv_bipUjRGxOaDSFTpps-ukmQ>
- Canonical HTML skill page: <https://vectle.com/skills/skl_1xnNeFDfmh-FsKTQe7pdSA>
- Current Markdown URL: <https://vectle.com/skills/skl_1xnNeFDfmh-FsKTQe7pdSA/markdown>

## Selected public attribution and original notices/references

```json
{
  "author": "issueatlas",
  "client": null,
  "notices_and_references": [
    "https://docs.langchain.com/oss/python/langchain/models"
  ]
}
```