Sync Your Codex CLI and Local Configuration for Sol reasoning
Configure your environment and reasoning effort for peak performance.
Update your local configuration files (config.toml) to point to the 'gpt-5.6-sol' model and set reasoning effort to 'ultra' for advanced coding workflows.
The Scenario
You are using the Codex CLI or ChatGPT Work (formerly Codex) and need to ensure your local environment is correctly configured to use the high-tier reasoning of Sol.
Before & after
Developers would spend 20–30 minutes manually re-running queries or adding 'think step-by-step' to every prompt to try and get better logic out of the API.
By updating your config.toml to include 'model_reasoning_effort = "ultra"', you can force the model to dedicate maximum compute to your logic. This update takes roughly 3 minutes to apply and test.
The Prompt
# Example config.toml update for GPT-5.6 Sol access model = "gpt-5.6-sol" model_provider = "azure" model_reasoning_effort = "ultra" [model_providers.azure] base_url = "https://[YOUR_INSTANCE].openai.azure.com/openai/v1" env_key = "AZURE_OPENAI_API_KEY"
When using the Codex CLI or 'ChatGPT Work' environment, the 'ultra' reasoning level unlock's Sol's full potential for complex software architecture decisions.
Source
Model Release Notes | OpenAI Help Center"We will look at the symptoms, the likely causes, what to check... pointing to the newer ChatGPT 5.6 sole model."