OpenAI API

Use the OpenAI Platform API with OPENAI_API_KEY. The Responses backend is the recommended path for current Codex and GPT agent models.

Add the key

export OPENAI_API_KEY="your-platform-api-key"

Keep this command out of shell history in managed environments. Prefer the platform's secret injection mechanism for CI.

Configure the provider

Add the shared provider and any models available to your OpenAI project:

[model_providers.openai]
base_url = "https://api.openai.com/v1"
api_backend = "responses"
env_key = "OPENAI_API_KEY"
context_window = 200000

[model.openai-codex]
model = "gpt-5.3-codex"
model_provider = "openai"
name = "GPT-5.3 Codex"

[model.openai-sol]
model = "gpt-5.6-sol"
model_provider = "openai"
name = "GPT-5.6 Sol"

[model.openai-terra]
model = "gpt-5.6-terra"
model_provider = "openai"
name = "GPT-5.6 Terra"

[model.openai-luna]
model = "gpt-5.6-luna"
model_provider = "openai"
name = "GPT-5.6 Luna"

[models]
default = "openai-sol"
session_summary = "openai-sol"
prompt_suggestion = "openai-sol"

The 200000 context value is a conservative local compaction ceiling. Replace it with the documented limit for the exact model if that limit is lower.

Verify

grok \
  -p "Reply with exactly: MODEL_OK" \
  -m openai-sol \
  --max-turns 1 \
  --no-subagents \
  --disable-web-search \
  --no-memory \
  --output-format json

The Responses client sends store: false by default. OpenAI account policy and applicable API terms still determine provider-side handling.

Codex model versus Codex login

Using a model with codex in its ID does not require Codex subscription authentication when the model is available to your Platform API project. It is still a normal OPENAI_API_KEY request to api.openai.com.

ChatGPT/Codex subscription authentication is a different route. See Codex authentication.

Availability errors

If OpenAI returns model_not_found, the model is not visible to that Platform project or API key. Choose a model returned by the account's model catalog; do not assume that access in the Codex app implies access through the Platform API.

Official references:

• OpenAI API authentication
• Responses API