Which coding agents can use GPT-6.1 Terra?

As of 2026-10-26 (America/Chicago), GPT-6.1 Terra is confirmed natively in GitHub Copilot, the Codex CLI and ChatGPT Work, and in OpenAI's API. We could not confirm it in Cursor (its model docs list GPT-5.6 models only), Cline or the OpenCode picker, and Claude Code's docs describe only Claude models. We have not enabled Terra in any tool ourselves.

By Agentic Weekly, operated independently from Texas, US · Last updated Oct 26, 2026 (America/Chicago) · How we work

Checked Oct 26, 2026 by Agentic Weekly's editorial process: vendor docs re-read.

Last verified: 2026-10-26 (America/Chicago) · Versions covered: Codex CLI 0.159.0 or later required for Terra per OpenAI; other tools: docs and changelogs read 2026-10-26, no versions run · Evidence: Reported (see “What we tested”)

GPT-6.1 Terra availability by coding agent

"Confirmed" below means a vendor page we read on 2026-10-26 says so. "Not confirmed" means we found no vendor statement either way; it does not mean the tool cannot use Terra. Rollouts are gradual, so recheck before you plan around a row.

Where GPT-6.1 Terra works in coding tools, read from vendor docs on 2026-10-26 (America/Chicago)
Tool	Native support	Via your own key or gateway	Plan or version needed	Source
GitHub Copilot	Confirmed: generally available, selectable in the model picker in VS Code, Visual Studio, Copilot CLI, cloud agent, the Copilot app, github.com, GitHub Mobile, JetBrains IDEs, Xcode and Eclipse	Not needed; billed at provider list pricing under usage-based billing	Copilot Pro, Pro+, Max, Business or Enterprise; gradual rollout; admins control it by model policy	GitHub changelog
Codex CLI	Confirmed: `codex -m gpt-6.1-terra`	API access to Terra is listed by OpenAI; we did not read the API-key setup steps	Codex CLI 0.159.0 or later; OpenAI says Plus, Pro, Enterprise and Edu users	Codex models, OpenAI launch post
Codex IDE extension	Not listed for Terra on OpenAI's page (it is listed for GPT-6.1 Sol)	Not confirmed	Not applicable	Codex models
ChatGPT Work (desktop app and web)	Confirmed: choose it under Advanced in the model list	Not applicable	Plus, Pro, Enterprise and Edu per OpenAI's launch post	Codex models
Cursor	Not confirmed: Cursor's model docs list GPT-5.6 Sol, Terra and Luna and no GPT-6 family model; its changelog's latest entry we saw is dated Oct 20, 2026	Not confirmed	Cursor's docs say third-party models bill at API list price on Premium and above	Cursor models, Cursor changelog
Claude Code	Not confirmed: its model docs describe Claude aliases (opus, sonnet, haiku, fable)	Not confirmed: the docs say ANTHROPIC_BASE_URL changes where requests are sent, not which model answers them, and point to LLM gateways	Not applicable	Claude Code model config
Cline	Not confirmed	Cline's OpenAI provider takes an OpenAI API key or OpenAI Codex sign-in and lets you pick a model from a list; we did not confirm Terra is in that list	OpenAI API key or account	Cline OpenAI docs
OpenCode	Not confirmed in its picker	OpenCode says it uses the AI SDK and Models.dev to support 75+ providers; Models.dev lists `gpt-6.1-terra` under the openai provider (read 2026-10-26)	Provider API key added with /connect	OpenCode providers, Models.dev

Not checked: Gemini CLI and other tools. We have not enabled Terra in any of these tools, so every cell is a reading of documentation, not a test.

GitHub Copilot: plans and rollout

GitHub's changelog for 2026-10-26 says GPT-6.1 Terra is generally available in Copilot for Pro, Pro+, Max, Business and Enterprise users, is designed for everyday agentic coding and terminal work at a lower cost than GPT-6.1 Sol, and is billed at provider list pricing under usage-based billing. It says rollout is gradual, so you may not see it yet. Copilot Business and Enterprise administrators manage access through the model policy in Copilot settings; under default model enablement new models are turned on unless an administrator has turned off the global default or disabled this model. GitHub's supported-models page lists both GPT-6.1 Terra and GPT-6.1 Sol as generally available.

Codex (CLI and IDE) and ChatGPT Work

OpenAI's launch post says Terra is available to all Plus, Pro, Enterprise and Edu users in ChatGPT Work and Codex, and through the API as gpt-6.1-terra. Its Codex page says Terra needs Codex CLI 0.159.0 or later and is started with codex -m gpt-6.1-terra; in the ChatGPT desktop app and ChatGPT Work on the web you open Advanced and choose it from the model list. The page lists the Codex IDE extension for Sol but not for Terra. The launch post also says the same usage allowance in ChatGPT Work and Codex covers more tasks with Terra than with Sol or Astra.

Cursor, Claude Code, Cline and OpenCode: native or bring your own key

Cursor: its models page listed GPT-5.6 Sol, Terra and Luna and no GPT-6 models when we read it, so we mark Terra not confirmed. That page may lag a release; check the in-app model list.
Claude Code: built around Claude models. Its docs say ANTHROPIC_BASE_URL changes where requests are sent, not which model answers them. If you need Terra in a Claude-style workflow, a Terra-capable tool above is the documented path.
Cline: supports the OpenAI API with a key or OpenAI Codex sign-in. Whether Terra appears in its model dropdown is not something we confirmed.
OpenCode: draws on Models.dev, where gpt-6.1-terra is listed under the openai provider (and under other providers such as GitHub Copilot and OpenRouter). That makes a working setup likely but we did not confirm it in OpenCode itself.

Which to use for what

Already on Copilot Pro or higher: select Terra in your editor's model picker once it appears, and compare it with your current model on a few real tasks.
Terminal agent on a ChatGPT plan: Codex CLI with -m gpt-6.1-terra.
Cursor, Cline or OpenCode user: check the in-tool model list first; if Terra is missing, an OpenAI API key plus a provider setting is the usual route, but confirm it in that tool's own docs.
Claude Code user: stay with Claude models, see which Claude model should you use, or compare costs in GPT-6.1 Terra vs Claude Opus 5.5.
Choosing between OpenAI models for coding: GPT-6.1 Terra vs GPT-6.1 Sol. For tools generally: best AI coding agents.

What we tested

Nothing: we have not enabled GPT-6.1 Terra in any tool. Each matrix cell is a statement from that tool's or vendor's own documentation, changelog or announcement as read on 2026-10-26, or "not confirmed" where we found none.

GitHub Copilot: A sensible default if your team already lives on GitHub; check which plan you need for new models. Reported (not run by us).
Codex CLI: A quality-of-life release: worth updating if you re-type the same prompts or switch models a lot, not a reason to switch tools. Tested (smoke test, 2026-10-25, local Qwen2.5-3B-Instruct, not vendor models).
Cursor: Worth a look if you run agents on several repos or want one place for editor, cloud agents and Git hosting; the October changes are mostly for teams. Reported (not run by us).
Claude Code: Update now if you use the sandbox or run Claude Code on a cloud provider; skip if you wanted flashy new features, this is a hardening release. Tested (smoke test, 2026-10-25, local Qwen2.5-3B-Instruct, not vendor models).
Cline: A good open-source pick if you want an agent inside your IDE or a CLI and an SDK to embed it; the October notes are incremental. Reported (not run by us).
opencode: Update when convenient for the runtime security fixes; pick opencode if you want an open-source agent that is not tied to one model vendor. Tested (smoke test, 2026-10-25, local Qwen2.5-3B-Instruct, not vendor models).

FAQ

Is GPT-6.1 Terra in Cursor?

Not confirmed. Cursor's model docs, read 2026-10-26, list GPT-5.6 Sol, Terra and Luna and no GPT-6 family models, and Cursor's changelog entry we saw most recently is dated Oct 20, 2026. Check the in-app model list.

Is GPT-6.1 Terra in Claude Code?

Not natively as far as the docs show. Claude Code's model docs list Claude aliases, and say ANTHROPIC_BASE_URL changes where requests are sent, not which model answers them. We did not confirm any gateway that routes it to Terra.

Is GPT-6.1 Terra in GitHub Copilot, and which plan?

Yes. GitHub says it is generally available to Copilot Pro, Pro+, Max, Business and Enterprise users, with a gradual rollout, selectable in editors, Copilot CLI, the cloud agent, github.com and mobile.

Can I use my own OpenAI key in Cline or OpenCode?

Both document OpenAI API access. Cline's docs describe an API key or OpenAI Codex sign-in with a model dropdown; OpenCode uses Models.dev, which lists gpt-6.1-terra under the openai provider. We did not confirm Terra in either tool's own picker.

Is GPT-6.1 Terra free in Codex?

OpenAI's launch post lists Plus, Pro, Enterprise and Edu users for ChatGPT Work and Codex. It does not list free plans, and we did not find any statement that Terra is free.

Have you tested GPT-6.1 Terra in these tools?

No. We have not enabled GPT-6.1 Terra in any coding tool. The matrix is built from vendor documentation, changelogs and the Models.dev listing read on 2026-10-26, and "not confirmed" means we found no statement, not that it is unavailable.

Sources

GitHub changelog: GPT-6.1 Terra in GitHub Copilot (fetched 2026-10-26)
GitHub Docs: supported AI models in Copilot (fetched 2026-10-26)
OpenAI: Codex and ChatGPT Work models (fetched 2026-10-26)
OpenAI: Introducing GPT-6.1 Terra (Internet Archive capture; openai.com blocks scripted fetches) (fetched 2026-10-26)
OpenAI API: GPT-6.1 Terra model page (fetched 2026-10-26)
Cursor docs: models and pricing (fetched 2026-10-26)
Cursor changelog (fetched 2026-10-26)
Claude Code docs: model configuration (fetched 2026-10-26)
Cline docs: OpenAI provider (fetched 2026-10-26)
OpenCode docs: providers (fetched 2026-10-26)
Models.dev provider and model data (fetched 2026-10-26)

Page history

Oct 26, 2026: First published. GitHub's changelog and supported-models page, OpenAI's Codex page, launch post and model page, and the Cursor, Claude Code, Cline and OpenCode docs read on this date; nothing was enabled or run. Recheck planned weekly while rollouts continue.

Markdown version for agents: /guides/gpt-6-1-terra-in-coding-agents.md

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