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

# LangChain

> Use authsome with LangChain. Pull fresh tokens at agent construction or run the whole chain under the proxy.

[LangChain](https://www.langchain.com) reads provider credentials from environment variables or constructor arguments. The recommended setup: run the chain under authsome's proxy and let LangChain's SDKs read the placeholder env vars unchanged.

## Run the whole chain under the proxy

```bash theme={null}
authsome login openai
authsome login github
authsome run -- python my_chain.py
```

LangChain SDKs read placeholder env vars (`OPENAI_API_KEY=authsome-proxy-managed`) and initialize. The proxy substitutes the real key for outbound HTTPS to `api.openai.com`, `api.github.com`, and other matched hosts. No code changes to your chain.

## Tools that call out to providers

Many LangChain tools (`GitHubToolkit`, `SerpAPIWrapper`, `BraveSearch`, etc.) read their secret from an env var. With the proxy already wrapping the process, the existing wrappers just work:

```python theme={null}
from langchain_community.utilities import SerpAPIWrapper

# reads SERPAPI_API_KEY from env, which is the proxy placeholder
search = SerpAPIWrapper()
```

For tools that authsome doesn't bundle, add a [custom provider](/guides/custom-providers) so the proxy can match by host.

## Export when the proxy is not enough

If you're building a larger orchestrator around LangChain and need to pass tokens explicitly (different connection per call, or TLS-pinned SDKs that bypass the proxy), export credentials first:

```bash theme={null}
eval "$(authsome export openai --format env)"
eval "$(authsome export github --format env)"
```

Then construct LangChain clients as usual — they read the exported env vars.

## Async clients

`AsyncChatOpenAI` and other async wrappers work identically under `authsome run`.

## Multi-account workflows

```bash theme={null}
eval "$(authsome export github --connection work --format env)"
eval "$(authsome export github --connection personal --format env)"
```

See [Multiple connections per provider](/guides/multiple-connections).

## What's next

<Columns cols={2}>
  <Card title="Python library" icon="code" href="/reference/python-library">
    The full library surface.
  </Card>

  <Card title="OpenAI integration" icon="key" href="/integrations/api-key/openai">
    Set up the OpenAI key LangChain will use.
  </Card>
</Columns>