October 9, 2026
Codex displaced Claude in Hansson's workflow: the developer chose Sol 6.1
Hansson ties his choice to Sol 6.1, which OpenAI added to Codex on Sep 29.
DHH
@dhh
For the first time in a long while, I've preferred Codex as my main agent and kept Claude second. Sol 6.1 is remarkably good!
· 184K views
David Heinemeier Hansson has, for the first time in a long stretch, made Codex his main AI agent, with Claude as his second.
He used to switch models. On Jan 7, Hansson described working with Claude Opus 4.5, Codex 5 and Gemini 3 through OpenCode. Back then he highlighted switching between models and saving sessions to share. Now he prefers pairing Codex in the main role and praises Sol 6.1.
How to enable Sol. In Codex CLI, the model starts with `codex --model gpt-6.1-sol`. In an open session, `/model` switches the model and reasoning depth. On macOS and Linux, install the CLI with `curl -fsSL https://chatgpt.com/codex/install.sh | sh`, then run `codex` in the project directory and choose `Sign in with ChatGPT`.
Sol 6.1 works with the ChatGPT Plus subscription at $20 a month. As of Oct 9, OpenAI cites a range of 15–160 local messages per 5 hours depending on the task, with possible weekly limits. The model is also available on Pro, Business, Enterprise and Edu; Free and Go do not include it.
You can set Sol 6.1 as the default with the line `model = "gpt-6.1-sol"` in `config.toml`. This config is shared across the Codex app, the CLI and the IDE extension.
On Enterprise and Edu, an admin has to enable Sol 6.1, and the model is not available in Chat mode.
Source