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Codex CLI is OpenAI’s official command-line coding agent. Connect it to ClearMaas via a custom provider in config.toml or environment variables.

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Prerequisites

  • Codex CLI installed (npm install -g @openai/codex or via installer)
  • A ClearMaas API key starting with sk-

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Quick setup via environment variables

The fastest way to get started: 
export OPENAI_API_KEY="sk-..."
export OPENAI_BASE_URL="https://api.clearmaas.com/v1"
codex
(Older Codex versions may recognize OPENAI_API_BASE instead of OPENAI_BASE_URL �?set whichever your version expects.)

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Setup via config.toml

For persistent configuration, create ~/.config/codex/config.toml: 
model_provider = "clearmaas"

[model_providers.clearmaas]
name = "ClearMaas"
base_url = "https://api.clearmaas.com/v1"
env_key = "OPENAI_API_KEY"
Then set the API key in your environment: 
export OPENAI_API_KEY="sk-..."

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Adding a second provider (Anthropic)

You can define multiple providers and switch between them: 
model_provider = "clearmaas"

[model_providers.clearmaas]
name = "ClearMaas"
base_url = "https://api.clearmaas.com/v1"
env_key = "OPENAI_API_KEY"

[model_providers.anthropic]
name = "Anthropic Direct"
base_url = "https://api.anthropic.com/v1"
env_key = "ANTHROPIC_API_KEY"
Switch providers with the -c CLI flag: 
codex -c model_provider='"anthropic"' "Explain this function"

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Choosing a model

Set the default model in config.toml: 
model = "anthropic/claude-sonnet-4.6"
Or override per-invocation: 
codex -c model='"openai/gpt-4o-mini"' "Refactor this module"
Available prefixes for routing to different providers:
PrefixExample model ID
openai/openai/gpt-4o-mini
anthropic/anthropic/claude-sonnet-4.6
google/google/gemini-2.5-pro
deepseek/deepseek/deepseek-chat
grok/grok/grok-4-fast-reasoning
qwen/qwen/qwen3.6-plus
kimi/kimi/kimi-k2.6

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Adding custom headers

If your ClearMaas setup requires additional headers: 
[model_providers.clearmaas]
name = "ClearMaas"
base_url = "https://api.clearmaas.com/v1"
env_key = "OPENAI_API_KEY"

[model_providers.clearmaas.http_headers]
X-Custom-Header = "value"

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Verification

export OPENAI_API_KEY="sk-..."
export OPENAI_BASE_URL="https://api.clearmaas.com/v1"
codex "Hello, what model are you using?"
Check your ClearMaas dashboard to confirm the request was routed.

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See also