Codex (OpenAI)
A Tier · 8.3/10
OpenAI's cloud-based coding agent -- runs parallel tasks, proposes PRs, and lives inside ChatGPT
Score Breakdown
Benchmark Scores
Benchmarks for GPT-5.2-Codex (launched 2026-04-23 -- SOTA on SWE-Bench Pro and Terminal-Bench 2.0; first-party scores below pending detailed third-party verification)
| Benchmark | Description | Score | |
|---|---|---|---|
| SWE-bench | Real GitHub issue fixing | 72% | |
| HumanEval | Python code generation | 95% |
Last updated: 2026-04-25
The Good and the Bad
What we like
- +Lives inside ChatGPT -- if you already pay for Plus ($20/mo), Codex is included at no extra cost
- +Parallel task execution is a real differentiator -- assign 5 tasks at once and come back when they're done
- +Code review feature catches bugs and suggests improvements before you merge -- genuinely useful, not just a gimmick
- +Sandboxed environments per task means it can't break your local setup -- runs tests safely in the cloud
- +GitHub integration lets it propose PRs directly, read your repo, and work on real issues end-to-end
- +CLI, web, and IDE extension gives you three ways to interact depending on your workflow
What could be better
- −Usage limits burn through fast -- 20-100 messages per 5 hours on Plus means heavy users hit the wall mid-task
- −Can't be corrected mid-task -- once you send a prompt, you wait for the full result, no steering
- −Struggles with complex refactors and architectural decisions -- great at straightforward tasks, mediocre on nuanced ones
- −Cloud-based GitHub integration is unintuitive to set up -- many users find the workflow confusing
- −No image input yet -- can't show it a screenshot of a UI bug and ask it to fix it
- −Response latency can spike to 3+ minutes per response during peak hours
Pricing
Free
- ✓Basic Codex access
- ✓Quick coding tasks only
- ✓Explore capabilities
Go
- ✓Lightweight coding tasks
- ✓Codex CLI access
Plus
- ✓Codex web + CLI + IDE extension
- ✓GPT-5.4 + GPT-5.3-Codex
- ✓20-100 local messages per 5h
- ✓Slack integration
- ✓Cloud code review
Pro
- ✓10-20x higher rate limits
- ✓GPT-5.3-Codex-Spark (research preview)
- ✓Up to 2,000 messages per 5h
- ✓Priority processing
Business
- ✓30-150 local messages per 5h
- ✓10-60 cloud tasks per 5h
- ✓20-50 code reviews per 5h
- ✓Admin controls
- ✓Larger VMs
Known Issues
- GPT-5.2-Codex shipped 2026-04-23 as a coding-specialized variant separate from the consumer GPT-5.5 launch. Available to all paid ChatGPT users across Codex web/CLI/IDE surfaces today; API access in coming weeks. Posts SOTA on SWE-Bench Pro and Terminal-Bench 2.0. Improvements: long-horizon agentic coding via context compaction, large refactors and migrations, Windows env perf, and cybersecurity. Direct upgrade over GPT-5.3-Codex for serious agentic work -- if you're on Plus or Pro, your Codex defaults are already on the new modelSource: OpenAI: Introducing GPT-5.2-Codex (openai.com/index/introducing-gpt-5-2-codex/), OpenAI Codex changelog · 2026-04-23
- Codex Chronicle launched 2026-04-20/21 as an opt-in research preview for ChatGPT Pro on macOS only (NOT available in EU/UK/Switzerland). Captures screen content + builds persistent memories so Codex understands what you're working on without manual context-restating. Privacy details: screenshots stored locally in $TMPDIR/chronicle/screen_recording/ auto-deleted after 6 hours; generated memories live unencrypted as markdown at ~/.codex/memories_extensions/chronicle/; OpenAI servers don't retain processed screenshots and don't train on them. OpenAI explicitly flags 'increased prompt-injection attack surface from screen content' -- pause Chronicle before meetings or sensitive material. Currently consumes rate limits aggressively. Closest comparison is Microsoft Recall but with stronger local-storage guaranteesSource: OpenAI Chronicle docs (developers.openai.com/codex/memories/chronicle), Help Net Security, 9to5Mac · 2026-04
- Security vulnerability discovered where branch parameter allowed shell command injection during environment setup -- fixed by OpenAI with improved input validationSource: BeyondTrust Phantom Labs, TechRadar · 2026-03
- CLI was macOS-only at launch, frustrating Windows and Linux users -- broader platform support now rolling outSource: Reddit r/openai, GitHub issues · 2026-04
- Code quality for complex tasks often needs significant human review before merging -- better at code review than code writing according to developer feedbackSource: Hacker News, Reddit r/programming · 2026-04
- 2026-04-16 Codex 'super app' update is substantially bigger than the initial Mac-app control headline suggested. Full feature set per OpenAI: (1) macOS computer-use agent that opens apps, clicks, and types with its own cursor in background while you use your machine, (2) image generation via gpt-image-1.5 INSIDE Codex, (3) persistent memory + user preferences across sessions, (4) in-app browser built on the Atlas browser stack, (5) 90+ new plugins combining skills, app integrations, and MCP servers. OpenAI also disclosed 3M weekly Codex users with 70% month-over-month growth. Windows / Linux computer-use support still pending. Not available in EEA, UK, or SwitzerlandSource: BigGo Finance, gHacks, Blockchain News, OpenAI release notes · 2026-04
Best for
Developers already paying for ChatGPT Plus who want a coding agent at no extra cost. Especially good for parallel task execution -- assign multiple bug fixes or feature branches and let Codex work them simultaneously.
Not for
Developers who need fine-grained control mid-task (use Claude Code or Cursor instead). Also not ideal for complex architectural refactors where the AI needs human guidance throughout the process.
Our Verdict
Codex is OpenAI's answer to Claude Code and Devin, and it has one killer advantage: it's bundled with ChatGPT Plus. If you're already paying $20/mo for ChatGPT, you get a cloud coding agent for free. The parallel task execution is genuinely unique -- no other coding agent lets you fire off 5 tasks and check back later. But the rough edges are real: you can't steer it mid-task, complex refactors fall flat, and the usage limits feel tight. For straightforward coding tasks and code review, it's excellent. For anything nuanced, Claude Code's interactive approach is still better.
Sources
- OpenAI: Introducing GPT-5.2-Codex (2026-04-23) (accessed 2026-04-25)
- OpenAI Codex changelog (accessed 2026-04-25)
- OpenAI Chronicle docs (Apr 2026) (accessed 2026-04-22)
- Help Net Security: Chronicle screen-context memories (accessed 2026-04-22)
- OpenAI official Codex page (accessed 2026-04-17)
- developers.openai.com/codex/pricing (accessed 2026-04-17)
- VentureBeat: Codex Mac-app control + GPT-Rosalind launch 2026-04-16 (accessed 2026-04-17)
- Reddit r/openai, r/programming (accessed 2026-04-17)
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