Codex vs Cursor: OpenAI's coding agent vs an AI editor

Cursor is an AI code editor built on VS Code, with its own agent, Tab autocomplete and models from several labs, and it suits developers who want AI inside the editor they use all day. Codex is OpenAI's coding agent for the terminal, IDEs, the ChatGPT desktop app and the cloud, included with ChatGPT plans, and it suits developers who already pay for ChatGPT or want OpenAI's newest GPT-6 models.

You can also use both. OpenAI's Codex extension installs in Cursor, and both tools read AGENTS.md files and skills in .agents/skills, so a team can keep one set of instructions.

Product details below come from Cursor's and OpenAI's docs and pricing pages as of October 12, 2026. Usage and bug data come from Bug Bench, cubic's public benchmark of bugs found in AI-written code during review. For more agents side by side, see our guide to the best AI coding tools and agents, with Bug Bench data.

Cursor vs Codex at a glance

Codex prices as listed on OpenAI's Codex pricing page on October 13, 2026. Cursor sells individual and team plans, listed on cursor.com/pricing.

Where each one runs

Cursor

Cursor is a desktop editor "based upon the VS Code codebase", with a one-click import of your VS Code setup. Around the editor:

• Agent: a side panel that takes on multi-step coding tasks, edits code and runs terminal commands.

• Tab: autocomplete that suggests code as you type, based on your recent edits, surrounding code and linter errors.

• Agents Window: an agent-first view, generally available since Cursor 3 on April 2, 2026, for running many agents in parallel, locally or in the cloud.

• CLI: agent on macOS, Linux, WSL and Windows, with agent -p for scripts and CI.

• Cloud agents: agents in isolated cloud VMs.

• JetBrains: Cursor's agent in IntelliJ IDEA, PyCharm, WebStorm and other JetBrains IDEs through the Agent Client Protocol, on a paid plan.

Codex

Codex runs in four places:

• Codex CLI: macOS, Linux and Windows, installed with a standalone installer, npm or Homebrew. codex exec runs it from scripts and CI pipelines.

• IDE extension: VS Code, Cursor and Windsurf. Xcode and JetBrains IDEs have their own Codex integrations.

• ChatGPT desktop app: macOS and Windows, with a Linux install guide.

• Codex cloud: tasks in cloud environments, started from ChatGPT on the web, mobile or desktop, or from the CLI.

If you already use Cursor, the IDE extension is the line that matters. OpenAI lists Cursor as a supported editor for the Codex extension. Click the Codex icon, or run Codex: Open Codex Sidebar from the Command Palette, and OpenAI's agent sits next to Cursor's own.

Models

Cursor offers Claude, GPT, Gemini and other model families, plus Grok and Composer, which its docs class as first-party Cursor models. Its models and pricing page has the current list. As of October 12, 2026, its newest OpenAI models are GPT-5.6 Sol, Terra and Luna.

Auto picks a model for each request. On Teams and Enterprise, Cursor Router makes that choice in Cost, Balance or Intelligence mode. Cursor became part of SpaceX in August 2026.

Codex runs OpenAI's models. OpenAI's models page recommends GPT-6.1 Sol for complex coding and agentic workflows, saying it "offers near-Astra performance for complex work at a lower cost than Astra." It suggests Luna for focused, repeatable tasks. GPT-5.6 Sol, Terra and Luna "remain available during the rollout." With an API key, you get the API models available to that key.

For GPT-6.1 Sol or GPT-6 Astra, use Codex, because Cursor's models page lists no GPT-6 models as of October 12. For Claude, Gemini or Grok in the same picker as GPT, use Cursor. Bug Bench ranks seven Claude and GPT models by the bugs found in their code; see the best LLM for coding, ranked on Bug Bench.

Context, rules and shared files

How each agent finds and follows context

Cursor's agent searches with Instant Grep, which "builds and queries its index on your machine." Cursor says it "does not upload file paths or code to build a search index, and it does not store embeddings of your codebase for search." For broad questions, an Explore subagent searches in its own context window and reports back what it found.

Codex reads AGENTS.md files "before doing any work". It starts with a global file in ~/.codex, then adds one file per directory from the project root down to where you launched it. Files closer to your working directory override earlier guidance.

Search finds what the agent looks for. Code it never opens can still break, which is the subject of why AI code assistants break your build.

Cursor rules

Cursor rules come in a few forms:

• Project rules: .mdc files in .cursor/rules/, with frontmatter that decides when each one applies.

• AGENTS.md: plain Markdown in the project root or any subdirectory. Nested files combine with their parents, and the more specific instructions win.

• User Rules and Team Rules: your own preferences, and rules set for a whole team.

What carries across

• AGENTS.md works in both, so keep shared conventions there and Cursor-only, file-scoped rules in .cursor/rules/.

• Skills: Codex scans .agents/skills from your working directory up to the repo root, and Cursor loads .agents/skills/ too. Cursor also reads .codex/skills/ for compatibility.

• MCP servers: both support them, configured separately, in mcp.json for Cursor and config.toml for Codex.

• Moving from Cursor: the ChatGPT desktop app and the Codex CLI can import from Cursor, bringing over instructions, settings, skills and plugins. The import doesn't change your Cursor setup.

Rules tell an agent what you want. They don't check what it wrote; that is a review job, covered in how to configure coding agents that follow your team's standards.

Cloud agents

Both tools run tasks on remote machines while you work on something else. They differ in setup and billing.

Cursor's cloud agents run in isolated VMs with full development environments. They can build and test the software they changed, and use the desktop and browser to try it. You can start one from:

• the desktop app, the web at cursor.com/agents, or the iOS app

• Slack, Linear or the API

• an @cursor comment on a GitHub pull request or issue, or on a Bitbucket pull request

They clone from GitHub, GitLab, Azure DevOps Services or Bitbucket Cloud, work on a separate branch and push changes back for handoff. You set up the environment with agent-led setup, a saved snapshot or a Dockerfile in .cursor/environment.json. Cloud agents bill at API pricing for the model you select. Each one has its own machine, so it never stops to ask for approval.

Codex cloud starts from a cloud environment. You choose GitHub repositories, and Codex inspects them, installs dependencies and tools, and tests the setup before you publish the environment. Each task gets its own workspace and keeps working while your computer is asleep. When it finishes, you review the changes, ask for follow-ups, and commit or open a pull request. You start tasks from ChatGPT on the web, mobile or desktop, or from the CLI. Cloud tasks need a ChatGPT sign-in, because the API key option has no cloud features.

The practical difference is cost. A long Cursor cloud run spends tokens at the model's API price. A Codex cloud task spends your ChatGPT plan's allowance, and OpenAI's pricing page notes that cloud tasks may use more of it than local messages.

Safety defaults on your machine

Both tools can sandbox the agent's shell commands.

• Codex runs local commands in an OS-enforced sandbox with network access off by default. It uses Seatbelt on macOS, a native sandbox on Windows, and bubblewrap on Linux and WSL2, which you install first. An approval policy decides when Codex asks you before it leaves the sandbox or uses the network.

• Cursor uses Run Modes. In Auto-review, which Cursor calls "the safest useful setup for most people," allowlisted calls run right away and other shell commands run in a sandbox when possible. That sandbox blocks writes outside approved paths and network access by default, and protects paths like .git/config and .git/hooks. In Allowlist mode, only allowlisted actions run without approval, and Run Everything runs every tool call automatically.

Pricing

Codex

Codex comes with ChatGPT plans. From OpenAI's Codex pricing page on October 12, 2026:

• Free ($0) and Go ($8/month): GPT-6 Luna at Standard speed in the desktop app, subject to rollout.

• Plus ($20/month): Codex on the web, in the CLI, in the IDE extension and on iOS, with GPT-6.1 Sol and GPT-6 Luna. ChatGPT credits extend usage.

• Pro (from $100/month): plans at $100, $200 or $500 a month, with no five-hour limit at present.

• Business, Enterprise and Edu: Codex in a team workspace with admin controls.

• API key: the CLI, SDK and IDE extension at API prices, without cloud features.

On Plus and Standard Business, usage is counted per five-hour period, and weekly limits may also apply. OpenAI estimates 15 to 160 local GPT-6.1 Sol messages per five hours on Plus, depending on the task.

Cursor

Cursor sells individual and team plans, listed on cursor.com/pricing. It bills third-party models such as Claude, GPT and Gemini at their API list price, and its models and pricing docs explain how usage is counted.

If you mostly want GPT models, the two bill them differently. In Codex signed in with ChatGPT, GPT usage comes out of your plan's allowance. In Cursor, GPT-5.6 usage is billed at the model's API list price.

What Bug Bench shows about Codex and Cursor

Bug Bench ranks AI coding models by the bugs found in the code they write, and it also tracks coding agents. A counted bug is a cubic review finding on AI-written code that a developer upvoted or an AI coding agent addressed. The relative bug rate is counted bugs per AI-attributed line, divided by the rate across all AI-attributed lines in the window, so 1.00 is average and lower is better. Two models are statistically tied when their 95% confidence intervals overlap.

The data is observational, not causal. Teams choose their tools and models, so a rate reflects the work each one was used for as well as the model.

Share of AI-written code

These shares describe AI-written code reviewed by cubic, not the whole market.

Codex wrote 18.8% of that code in the week of October 5, down from its peak of 38.4% in the week of August 24. Cursor wrote 1.6%. It peaked at 10.4% in the week of August 17 and has been under 4% every week since. Claude Code wrote most of the rest, 78.1% (AI coding statistics), and we compare it with each of these tools in Codex vs Claude Code and Cursor vs Claude Code.

Models ranked inside each agent

Each rate compares one model's code, written through one agent, with the average across all AI-written code. Bug Bench doesn't publish a single bug rate per agent, so this table doesn't say which tool writes fewer bugs.

One model in both tables. GPT-5.6 Sol is at 0.62 inside Codex and 1.52 inside Cursor. Bug Bench doesn't report a test for differences between agents, and different teams gave each tool different work, so the gap doesn't show that an agent changes a model's output. Treat it as a reason to break down your own bug data by tool and model.

OpenAI's recommended model has two weeks of data. GPT-6.1 Sol came in at 1.22 inside Codex, statistically tied with GPT-6 Astra at 1.13, and first appeared in the data in the week of September 28. GPT-5.6 Sol, which OpenAI says remains available during the rollout, had the lowest rate inside Codex and ranks first of seven models across all agents at 0.65.

Cursor's ranking is thin. Only two models are ranked inside Cursor, and they are statistically tied, with both point estimates above average. The top one, Claude Opus 5, is listed as hidden by default on Cursor's models page as of October 12.

Which one to use

• You want AI in your editor, with suggestions as you type: Cursor.

• You want Claude, Gemini, Grok and GPT in one model picker: Cursor.

• You already pay for ChatGPT: Codex is included, so try it before adding another subscription.

• You want GPT-6.1 Sol or GPT-6 Astra: Codex.

• You want an agent CLI you can read and fork: the Codex CLI is open source under Apache-2.0, in openai/codex.

• You want both: install the Codex extension in Cursor, and keep shared instructions in AGENTS.md and shared skills in .agents/skills.

Whichever you choose, the agent's pull requests still need review before they merge. On GitHub, cubic reviews each pull request, learns your team's rules and reads files like AGENTS.md and .cursor/rules/ as context. Our AI code review guide covers how AI review works.

FAQ

Is Cursor better than VS Code with Codex?

It depends on what you want around the agent. VS Code with the Codex extension gives you OpenAI's agent and GPT-6 models on your ChatGPT plan. Cursor adds Tab autocomplete, its own agent, cloud agents and models from several labs, and the Codex extension installs in Cursor too, so you don't have to give up either.

Should I pay for Cursor or Codex?

If you already pay for ChatGPT, start with Codex, since it's included. ChatGPT Plus costs $20 a month on OpenAI's pricing page as of October 13, 2026, and Cursor sells individual and team plans, listed on cursor.com/pricing. Pay for Cursor when you want an AI editor with autocomplete and models from several labs, and remember that it bills third-party models such as Claude and GPT at their API list price.

Can I use Codex inside Cursor?

Yes. OpenAI's docs list Cursor, along with VS Code and Windsurf, as an editor for the Codex extension. Open it from the Codex icon or with Codex: Open Codex Sidebar in the Command Palette, then sign in with ChatGPT or an OpenAI API key. Codex usage counts against that ChatGPT plan or API key.

Is Codex free?

In part. ChatGPT Free and Go include Codex with GPT-6 Luna at Standard speed in the desktop app, subject to rollout, according to OpenAI's pricing page on October 12, 2026. ChatGPT Plus, at $20 a month, adds Codex in the CLI, the IDE extension, on the web and on iOS. Cursor also has a free tier with limited agent requests.

Is Codex or Cursor used more?

By share of code in Bug Bench's data, Codex. It wrote 18.8% of the AI-written code in the week of October 5, 2026, and Cursor wrote 1.6%. That data covers code reviewed by cubic, not the whole market, and weekly shares move: Codex reached 38.4% in the week of August 24, and Cursor 10.4% in the week of August 17.