For the complete documentation index, see llms.txt. Markdown versions of all docs pages are available by appending .md to any docs URL.

OpenAI

Configuration and setup for OpenAI LLM provider

Configure OpenAI as an LLM provider in agentgateway.

Configuration

# yaml-language-server: $schema=https://agentgateway.dev/schema/config

llm:
  models:
  - name: "*"
    provider: openAI
    params:
      apiKey: "$OPENAI_API_KEY"

Connect to Codex

Use agentgateway as a proxy to your OpenAI provider from the Codex client.

1. Create an agentgateway configuration without specifying a model, so the Codex client’s model choice is used.

   cat > config.yaml << 'EOF'
   # yaml-language-server: $schema=https://agentgateway.dev/schema/config
   
   llm:
     models:
     - name: openai
       provider: openAI
       params:
         apiKey: "$OPENAI_API_KEY"
   EOF

2. Point Codex at agentgateway through one of the following methods.

   Environment variableCLI overrideConfig file

   Codex uses the OPENAI_BASE_URL environment variable to override the default OpenAI endpoint. Use a base URL that includes /v1 so requests go to /v1/responses and OpenAI does not return 404.

   export OPENAI_BASE_URL="http://localhost:4000/v1"
   codex

   To override the base URL for a single run, set model_provider and the provider’s name and base_url (the -c values are TOML).

   codex -c 'model_provider="proxy"' -c 'model_providers.proxy.name="OpenAI via agentgateway"' -c 'model_providers.proxy.base_url="http://localhost:4000/v1"'

   To configure the base URL permanently, add the following to your ~/.codex/config.toml. For more information, see Advanced Configuration. The name field is required for custom providers.

   [model_providers.proxy]
   name = "OpenAI via agentgateway"
   base_url = "http://localhost:4000/v1"