OpenAI Codex release notes: GPT-6.1 Terra is now available

GPT-6.1 Terra is now available in OpenAI Codex and ChatGPT Work on Plus, Pro, Business, Enterprise, and Edu plans. OpenAI's October 26 changelog describes the model as fast and efficient for writing, visual understanding, and computer use, meaning performing tasks in a graphical interface.

Source: OpenAI: GPT-6.1 Terra in Work and Codex.

OpenAI Codex release notes: select Terra in the terminal

Codex CLI is OpenAI's terminal-based coding agent. Terra requires version 0.159.0 or later. Its model identifier is gpt-6.1-terra.

Human step

Start Codex with this terminal command:

codex -m gpt-6.1-terra

In an existing interactive session, use /model to switch models. The command above selects the model; it does not configure browser tools or computer access.

Source: OpenAI: model selection and Terra version requirements.

Availability and limits

Terra is not available in Chat and does not support UAE inference residency. Enterprise access depends on workspace availability and administrator controls. Browser tools and computer access have separate setup and permission requirements.

Source: OpenAI: Terra launch and availability.

Short example: use the new Codex feature

After selecting Terra, test its documented writing capability on the project's existing documentation:

Read the project's README. Rewrite the introduction so a new user understands what the project does and how to get started. Preserve verifiable facts and flag missing information. Show the proposal without changing the file.

• The proposal follows the documentation rather than assuming features.
• Instructions and version requirements retain their meaning.
• Missing information is clearly marked.