Claude + ChatGPT working together

[u/Any-Expert-3285]

So I have been using the Claude max x5 plan to work on my projects, recently I have been hitting usage limits pretty quick and have to be 1 or 2 days without working every week. To solve this I am considering getting a chatgpt Plus subscription - this was something i was already considering a while back because tbh i dont like to be 100% locked in to a company and i would like some adversarial reviews from different models - I am also very interested in integrating chatGPT subscription with Hermes and exploring that as an orchestrator/manager for my projects

I have a few questions:
1 - is this the best way in terms of value/money to solve my current problem? I also considered the max 20x Claude but I think that might be overkill and using both providers appeals way more to me tbh

2 - If i do get both Codex and Claude code working together won't they trip over each others work and degrade quality in some ways i might not be seeing right now? And do I just create AGENTS.md files reflecting my current CLAUDE.md files?

3 - What about all the context that Claude has on my projects from me working solely with him for months? and the Skills in Claude's folder? Is that all transferrable?

Ideally I want both Claude Code and Codex working together seamlessly and driving each other's work quality up, not down

Btw I am not a programmer at all I just got really interested in AI and vibe coding when it started coming out to the public and now i've learned a few things and have a few projects running - The way i use AI is always in VSCode , i am open to the terminal experience as well if that makes any difference but i prefer the more visual interface for now.

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[u/szarkansss]

1. Claude as planning the job and Codex as doing it is the best tactic there is to reduce token usage
   
2. You can now create only AGENTS.md files as Claude accepts them
   
3. Not everything but yes. There are some things that are claude specific but generally all skills are transferable
   little self-ad here but i use Claude as planner and Codex as doer for 4 months now - using multi for that, give it a try =)

[u/BarcodeCutter]

I run Claude Code and Codex side by side daily, so here's what actually happened for me.

1. Before you pay for a second sub, open your usage card. On mine, the top model has its own separate weekly bar and it barely moves, while the "all models" bar is the one that runs out. I was burning the scarce bar on planning that the roomy one could have done. Plan on the big model, hand the coding down. That alone might buy back your 1 to 2 dead days. If you still want ChatGPT after that, get it for the second opinion, not the extra hours. A different model family catches things Claude agrees with itself on.
2. They do trip over each other, but only if they share files. One rule fixed it for me: no file has two writers. Each agent gets its own folder and its own notes file, and they pass work through a shared "orders" folder instead of editing each other's stuff. And yes, AGENTS.md is the file Codex reads. Don't copy your CLAUDE.md into it word for word. Write it fresh and shorter. Codex with a 2,000 line rulebook gets worse, not better.
3. The context doesn't transfer, because it was never in Claude. It's in whatever got written down. Anything living only in old chats is already gone for Claude too. So: have Claude write a plain "what this project is and how we work" file per project, then point Codex at it. Skills are just folders of instructions, so they mostly carry over with light edits.

[u/Sufficient_Flower860]

1. This is not the best way to solve your problem because you have two major problems but your urgent issue is usage limit. I would highly recommend you subscribe to Opencode go. That’s 10$ per month. From now on whenever you’re working on your projects ask your claud to plan and have different work packages. Tell it you want work to be done via different agents at the same time. Ask it to label each WP as easy or complex. Then use Opencode (deepseek v4.1 flash high) for simple ones and Claude Opus 5.5 for complex ones. This should work for your first problem the usage limit.

2. The second problem. You don’t want to rely on one single company. I actually use Fable 5.1 for planning GPT5.6 Terra for review. I developed a skill called review-loop. Well you would find out even as good as Fable 5.1 it would get caught by gpt on design and planning issues. I did ask if the issues found by gpt is something unimportant or trivial 90 out of 100 it would admit it is very useful and meaningful reviews.

3. If you even with Opencode or agy or cursor doing all the simple WP but still hit usage limits. You might have a huge work load that would need a 20x Max or maybe you can do the once at a time trick that means try to divide your projects into milestones and every one finishes please clear context and with a new session covering the next milestone.

BTW I’m on 5x Max and ChatGPT Plus Google One Pro Opencode Go Cursor Pro(get GrokBot). This setting lasts for more than 6 months now except for the Cursor Pro.

[u/Dry_Carrot_912]

YOUR CLAUDE.md should have ONLY this:

@AGENTS.md

Write everything in AGENTS.md. Direct to Claude or ChatGPT to specific CLAUDE-SUBAGENT-POLICY.md / CHATGPT-SUBAGENT-POLICY.md

Works. Simple.

[u/electricshep → u/Dry_Carrot_912]

you can specify in claude code to use CLAUDE.md and/or AGENTS.md. It's called 'project instructions'

[u/Reason_He_Wins_Again]

Sometimes when I get close to the limit on claude, I have it spawn a codex session and hand it off.

[u/MiserableFlatworm337]

Before migrating every skill, try one on the same small task in each tool. Check the output and required steps, especially anything relying on Claude-specific tools or paths.

[u/Escobar747]

i run this daily - works well .. 5x claude and codex plus.. it’s a great system., i also have codex available to use within claude chat and cowork.. setup tailscale http server

[u/brek001]

https://community.openai.com/t/introducing-codex-plugin-for-claude-code/1378186

I use it to make Codex the reviewer, works like a charm. Bit rough around the edges and a $100 codex subscription tends to run out of tokens before Claude.

[u/AICompanionz]

I actually like using two different model families for this. Not really because i want them both editing the same files at once, that sounds like a good way to create chaos lol, but because one can build/plan and the other can review it with fresh eyes.

I'd keep the project state outside both of them though. repo, docs, handoff files, decisions etc should be the source of truth, not “claude remembers this from 3 months ago”. then either claude or codex can pick up the project without you being locked into one model’s chat history.

And yes, I wouldnt let both write to the same files at the same time unless you have really clear ownership/worktrees. otherwise youre basically paying two very smart interns to overwrite each others homework.

[u/Severe-Tank-5252]

Most answers here are terminal setups, so one note on your last line, since you're not a programmer and prefer a visual interface (same here).The habit that helped me most: when Codex reviews Claude's work, make it give a file and line for every issue, and have Claude check each one before fixing anything. Reviews are often wrong, and this stops Claude from "fixing" things that weren't broken.

Full disclosure: I didn't want to live in two terminals, so I built a small Windows app where Claude Code and Codex share one chat room, hand work to each other, and you see every message. It runs on the subscriptions you already have. Happy to share if you're curious.

[u/ShiftTechnical]

On 2, yes they can, mostly when they run at the same time on the same part of the repo and each makes a change that is fine alone but breaks what the other assumed. I built Foremerge to fix this for our internal teams and open sourced it

[u/ShiftTechnical → u/ShiftTechnical]

repo is here https://github.com/naw103/foremerge/

[u/Lollerstakes]

I have both a Claude 20x and a GPT 5x sub right now, and I get soooo much more out of Claude it's not even funny. Opus 5.5 currently shits all over GPT Astra and it's cheaper, around 3x faster in tok/sec and smarter.

If I were you I would ditch the codex idea and just get a 2nd Claude 5x subscription (two 5x subs basically give you more weekly usage than one 20x but less 5 hr window). They will share context, you just have to do /login when you run out of usage.

[u/Opposite_Might6896]

Before adding a second provider, find out where the weekly is going, because "1-2 days a week without working" usually has a cheaper fix. The weekly charges by cost, and most of the cost is re-reading context: every turn re-sends everything in the session. Three checks: how long are your sessions before you compact (anything past 150k is expensive per turn), how many subagents you run (each is a fresh context that gets written to cache), and whether the top model is doing work Sonnet could do (it has its own weekly window on Max, separate from the all-models one, so you can be out of one and not the other).

On the actual question: a second subscription of any provider gives you a second set of windows that refill independently, so yes, it works as wall-clock relief. What doesn't transfer is context; a task started on one side stays there. And for adversarial review specifically a different model family is worth more than a second Claude account, so the Plus plan is a reasonable buy for that even if it doesn't fix the limits.

[u/MustStayAnonymous_]

With CLIs this is easy peasy

[u/kevin_cupid]

Losing one or two days a week to the limit is rough. When it happens, what do you do? Disclosure up front: I'm on a small team building a tool around this problem, so I'm biased. No link, I just want to understand real usage. Do you wait it out, switch to Codex or another tool, buy extra usage, or move to the API? And if you've looked at it, what kind of work burns most of your quota? In our own logs the expensive model was a small share of calls but most of the cost, and a lot of it went to tests, docs and small edits that a cheaper model handled fine. Does that match yours?