Codex

Codex is a harness: it owns the agent loop and tools. BitRouter supplies its model route, fallback, policy, and metering.

Pick a mode

bro code codex                         # BitRouter conversation
bro run codex "Summarize this repo"   # headless ACP turn
bro codex                              # Codex's native interface

bro launch codex is the generic spelling of bro codex. It injects a temporary bitrouter model provider into the child process and does not edit ~/.codex/config.toml.

Verify the executable, daemon, and route before a long run:

bro launch codex --check

Select a model

Pin a daemon-routable model with BitRouter's option:

bro codex --model bitrouter/auto
bro launch codex --model openai/gpt-5-codex

Arguments after -- go directly to Codex. Avoid forwarding Codex -c or --config overrides that replace the injected provider; bro launch rejects known conflicting shapes.

Permanent configuration

Use a permanent provider block only when Codex must start outside bro launch:

model_provider = "bitrouter"

[model_providers.bitrouter]
name = "BitRouter"
base_url = "http://127.0.0.1:4356/v1"
wire_api = "responses"
# env_key = "BITROUTER_API_KEY"

For Cloud, use https://api.bitrouter.ai/v1, set env_key = "BITROUTER_API_KEY", and export a BitRouter key. An authenticated self-hosted daemon requires the same.

Harness versus subscription

This page routes the Codex application through BitRouter. To use a ChatGPT Plus or Pro plan as the source of tokens, configure the separate openai-codex subscription provider.