Codex CLI | Mixlayer Docs

Codex CLI supports custom model providers through the Responses API. A separate profile keeps Mixlayer isolated from your default Codex configuration.

Create a Mixlayer API key

Create an API key in the Mixlayer console, then export it in your shell:

$ export MIXLAYER_API_KEY="..."

See API Keys for more details on creating and managing keys.

Create a Mixlayer profile

Save the following as ~/.codex/mixlayer.config.toml:

1 model = "z-ai/glm-5.2"
2 model_provider = "mixlayer"
3 model_context_window = 262144
4 model_reasoning_effort = "high"
5 model_reasoning_summary = "none"
6 model_supports_reasoning_summaries = false
7 
8 [model_providers.mixlayer]
9 name = "Mixlayer"
10 base_url = "https://models.mixlayer.ai/v1"
11 env_key = "MIXLAYER_API_KEY"
12 wire_api = "responses"

This uses GLM 5.2, a 256K-context model suited to long-horizon coding, difficult reasoning, and tool-driven tasks. You can replace the identifier and context window with another model from the Models section.

Start Codex

$ codex --profile mixlayer

Your normal ~/.codex/config.toml remains unchanged.

Verify

Inside Codex, run:

/status

Confirm that the active model is z-ai/glm-5.2 and the model provider is mixlayer.