Codex CLI

Codex CLI provides powerful code generation and completion capabilities directly in your terminal.

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Installing Codex CLI

npm install -g @openai/codex

Configuring Codex CLI with FinOps

Codex CLI always prefers OAuth over custom API keys. Make sure you run /logout before configuring the FinOps gateway with Codex.

Update codex.toml

Add the FinOps base URL and credentials to your global ~/.codex/config.toml or project-specific .codex/config.toml:

export OPENAI_API_KEY=<bifrost_virtual_key>

openai_base_url="{AI_GATEWAY_URL}/openai/v1"
env_key="OPENAI_API_KEY"
model = "openai/gpt-5.4"

Always run codex from the same terminal session where you exported variables, or restart the terminal after changing your profile. GUI-launched terminals or IDEs may not pick up shell-profile exports unless the environment is configured there as well.

Using Non-OpenAI models

Codex CLI defaults to websocket mode for the Responses API and automatically falls back to HTTPS if the WebSocket connection fails. Non-OpenAI models are not supported in WebSocket mode, because in this mode, the server is expected to maintain the conversation context. If you are using non-OpenAI models, you must enable HTTPS mode.

To enable https for Codex CLI by default, add these settings in your config.toml:


model_provider = "openai_http"

[model_providers.openai_http]
name = "OpenAI HTTP"
wire_api = "responses"
supports_websockets = false
base_url = "{AI_GATEWAY_URL}/openai/v1"

Model Configuration

Use the --model flag to start Codex with a specific model:

codex --model openai/gpt-5-codex
codex --model openai/gpt-5.4-pro

You can also switch models mid-session with the /model command:

/model openai/gpt-5.4-pro
/model openai/gpt-5-codex

Using Non-OpenAI Models with Codex CLI

FinOps automatically translates OpenAI API requests to other providers, so you can use Codex CLI with models from Anthropic, Google, Mistral, and more. Use the provider/model-name format to specify any FinOps-configured model:

# Start with an Anthropic model
codex --model anthropic/claude-sonnet-4-5-20250929

# Start with a Google model
codex --model gemini/gemini-2.5-pro

# Switch mid-session
/model anthropic/claude-sonnet-4-5-20250929
/model mistral/mistral-large-latest

Supported Providers

FinOps supports the following providers with the provider/model-name format:

openai, azure, gemini, vertex, bedrock, mistral, groq, cerebras, cohere, perplexity, xai, ollama, openrouter, huggingface, nebius, parasail, replicate, vllm, sgl

Non-OpenAI models must support tool use for Codex CLI to work properly. Codex CLI relies on tool calling for file operations, terminal commands, and code editing. Models without tool use support will fail on most operations.