> ## Documentation Index
> Fetch the complete documentation index at: https://langchain-5e9cc07a-preview-codexf-1788227809-773f4d5.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Set up coding agents

> Configure Claude Code, Codex, Gemini CLI, and Deep Agents Code to route LLM calls through the LLM Gateway.

<Note>
  **Beta:** The LLM Gateway is in [beta](/langsmith/release-stages).
</Note>

Configure coding agents to use the standard LLM Gateway endpoint for centralized cost controls, observability, and audit trails. The gateway authenticates each caller, routes by model ID, enforces policies, and traces each call.

Claude Code can use the standard Anthropic Messages format, while Codex and Deep Agents Code can use the standard OpenAI-compatible formats. Gemini CLI uses Google's native API and requires [direct model access](/langsmith/llm-gateway-direct-model-access).

## Prerequisites

* Your [Organization admin](/langsmith/rbac#organization-admin) has enabled the gateway and completed any required [provider setup](/langsmith/llm-gateway-admin-setup).
* You have a workspace-scoped [LangSmith API key](/langsmith/create-account-api-key) with `gateway:invoke` and `workspaces:read` [permissions](/langsmith/organization-workspace-operations).
* For bring-your-own-key models, your workspace has the corresponding provider secret. [Gateway Credits models](/langsmith/llm-gateway-credits) do not require a provider secret.

Set your LangSmith API key before configuring a client:

```bash theme={null}
export LANGSMITH_API_KEY="lsv2_..._....cbed3e"
```

## Claude Code CLI

Claude Code supports two separate authentication methods. Choose one before configuring:

* **Workspace provider secret**: The organization manages billing and policies through a provider key stored in workspace secrets. Use this method for org-managed usage.
* **Claude subscription OAuth**: Anthropic bills LLM calls to the user's personal Claude Plus or Max subscription instead of the workspace provider secret, while LangSmith still enforces gateway permissions, policies, and tracing. Use this method when developers have their own subscriptions.

### Use a workspace provider secret

Set `ANTHROPIC_API_KEY` to your LangSmith API key. Claude Code reads these variables from your shell environment or from the `env` block in `~/.claude/settings.json`.

If your LangSmith deployment is on a regional or self-hosted instance, replace the gateway hostname in the examples below with your [regional gateway](/langsmith/llm-gateway-api-formats#use-a-regional-gateway) hostname.

#### Use Anthropic models only

Set `ANTHROPIC_BASE_URL` to the Anthropic-format gateway endpoint. The gateway infers the `anthropic/` provider prefix from the endpoint:

```bash theme={null}
export ANTHROPIC_BASE_URL="https://gateway.smith.langchain.com/anthropic/"
export ANTHROPIC_API_KEY="$LANGSMITH_API_KEY"

claude
```

#### Route model tiers across providers

Set `ANTHROPIC_BASE_URL` to the gateway root, then map each Claude model tier to a provider-prefixed gateway model ID:

```bash theme={null}
export ANTHROPIC_BASE_URL="https://gateway.smith.langchain.com"
export ANTHROPIC_API_KEY="$LANGSMITH_API_KEY"
export ANTHROPIC_DEFAULT_OPUS_MODEL="anthropic/claude-opus-5"
export ANTHROPIC_DEFAULT_SONNET_MODEL="openai/gpt-5.6-terra"
export ANTHROPIC_DEFAULT_HAIKU_MODEL="fireworks/accounts/fireworks/models/glm-5p2"

claude
```

The model IDs are examples. Map each tier to any model configured in your workspace secrets or available through [Gateway Credits](/langsmith/llm-gateway-credits); the gateway handles request translation across providers. For details, see [API formats](/langsmith/llm-gateway-api-formats#understand-translation-behavior).

<a id="use-claude-subscription-oauth" />

### Use Claude subscription OAuth

<Note>
  Claude subscription OAuth requires an active Claude Code Plus or Max subscription. If you are using a workspace Anthropic API key, use the [workspace provider secret](#use-a-workspace-provider-secret) method instead.
</Note>

Claude Code Plus and Max users can send their saved Anthropic OAuth credential through the gateway. This mode does not require an `ANTHROPIC_API_KEY` in workspace provider secrets.

Log in to Claude Code with your subscription, then configure the gateway:

```bash theme={null}
export ANTHROPIC_BASE_URL="https://gateway.smith.langchain.com/anthropic"
export ANTHROPIC_CUSTOM_HEADERS="X-Api-Key: $LANGSMITH_API_KEY"

claude
```

Treat the `ANTHROPIC_CUSTOM_HEADERS` value as a secret: it embeds your LangSmith API key, so keep it out of shell history, dotfiles, and shared configuration.

Claude Code uses and refreshes the OAuth credential from its saved login, including the required OAuth capability in the `anthropic-beta` header.

The LangSmith API key authenticates the gateway request and remains subject to gateway permissions and policies. The gateway forwards the OAuth bearer to Anthropic, so Anthropic bills the call to the user's Claude subscription instead of the workspace provider secret. To confirm calls route through the gateway, check that traces appear in the `gateway` tracing project as described in [Verify the setup](#verify-the-setup).

<Warning>
  Leave `ANTHROPIC_AUTH_TOKEN` and `ANTHROPIC_API_KEY` unset for this mode. Either variable takes precedence over the saved subscription login.
</Warning>

<Warning>
  Claude Desktop plugins break when the gateway is configured.
</Warning>

## Codex CLI

Codex uses the Responses API. Add the following to `~/.codex/config.toml` to call the hosted Kimi K3 model with Gateway Credits through the standard endpoint:

```toml theme={null}
model = "moonshotai/kimi-k3"
model_provider = "langsmith-gateway"

[model_providers.langsmith-gateway]
name = "LangSmith Gateway"
base_url = "https://gateway.smith.langchain.com/v1"
env_key = "LANGSMITH_API_KEY"
wire_api = "responses"
supports_websockets = false
```

Then run:

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

To use a bring-your-own-key model instead, replace `model` with its provider-prefixed ID, such as `openai/gpt-5.4-mini`.

<Warning>
  Codex Desktop plugins break when the gateway is configured. The TOML configuration forces authentication through the gateway, so OpenAI no longer handles plugin authentication directly.
</Warning>

## Gemini CLI

Gemini CLI sends Google's native Generate Content requests, which the standard endpoint does not expose. Follow [Direct model access](/langsmith/llm-gateway-direct-model-access#configure-provider-sdks) to configure the `/gemini` route, then run:

```bash theme={null}
gemini
```

## Deep Agents Code

Use the OpenAI-compatible client with the standard endpoint, then pass the hosted model slug through the `openai` integration:

```bash theme={null}
export OPENAI_BASE_URL="https://gateway.smith.langchain.com/v1"
export OPENAI_API_KEY="$LANGSMITH_API_KEY"

dcode --model openai:moonshotai/kimi-k3
```

To use a bring-your-own-key model, keep the standard base URL and pass a provider-prefixed model after `openai:`, for example, `openai:anthropic/claude-opus-5`. For provider-native integrations and model IDs, see [Direct model access](/langsmith/llm-gateway-direct-model-access#configure-langchain-and-deep-agents).

## Company-wide deployment

For organizations rolling the gateway out to all developers, distribute the configuration through mobile device management or a shared shell profile. Distribute:

1. The standard gateway base URL for each client.
2. A workspace-scoped [LangSmith API key](/langsmith/create-account-api-key) per user or team, depending on your policy granularity.
3. The model IDs approved for each coding agent.
4. The Codex `config.toml` if your organization uses Codex.

Provider API keys stay centralized in LangSmith workspace secrets. Gateway Credits models do not require provider API keys.

## Verify the setup

After configuring a coding agent, make a test call and confirm that:

1. The call succeeds and the agent receives a response.
2. A trace appears in the `gateway` or `gateway-<short_api_key>-<api_key_id>` tracing project in your LangSmith workspace.

If the call fails with a `403`, check that your API key's role includes `gateway:invoke` and `workspaces:read`. If a bring-your-own-key call fails with a `400` mentioning a missing provider key, ask your organization admin to add the provider's key to workspace secrets.

## Next steps

* [Gateway Credits](/langsmith/llm-gateway-credits): call hosted models without a provider secret.
* [Direct model access](/langsmith/llm-gateway-direct-model-access): configure provider-native routes for coding agents that require them.
* [Spend policies](/langsmith/llm-gateway-spend-policies): set cost limits on developer LLM usage.
* [Traces, Engine, and access control](/langsmith/llm-gateway-access): understand where gateway traces appear.

***

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