You10:05
To @apiReplied in 95 min
@api add refunds to the billing API. Plan first, then build.
Codex vs Claude Code: use both on one project
You can run both: Claude Code builds and Codex reviews, or the other way round. Each session starts fresh and reads its own instructions. Here is where the two differ, and how one thread of notes lets each pick up where the other stopped.
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See them side by sideAt a glance
- Claude Code
- Runs on your Claude plan or an Anthropic API account. Reads CLAUDE.md, or AGENTS.md in its place.
- Codex
- Runs on your ChatGPT plan or an OpenAI API key. Reads AGENTS.md.
- Both
- Connect MCP servers and use skills. With ThreadPage Pro, both read and add to the same notes through the ThreadPage plugin.
- Between them
- One thread per project, where each session leaves its note for the next.
Codex and Claude Code, side by side
Checked 7 November 2026 in Anthropic’s and OpenAI’s documentation.
| Claude Code | Codex | |
|---|---|---|
| Where it runs | Terminal, VS Code and JetBrains, a desktop app, the web, the Claude app on phones | CLI, IDE extension, Codex Cloud, ChatGPT on desktop, web and phones |
| What you pay with | A Claude subscription or an Anthropic API account | A ChatGPT plan, such as Plus, Pro or Business, or an OpenAI API key |
| Instructions it reads | CLAUDE.md, or AGENTS.md in its place | AGENTS.md |
| Extensions | MCP servers, skills and plugins | MCP servers, skills and plugins |
Sources: code.claude.com/docs/en/overview, code.claude.com/docs/en/memory, learn.chatgpt.com/docs
One AGENTS.md for both
Codex reads AGENTS.md, and Claude Code can read AGENTS.md in place of CLAUDE.md. Auto memory stays with Claude Code. With Pro, both read and add to the same ThreadPage notes.
A thread, over time Example
Your workspace starts empty.
Work
Billing API
Mon 2 Nov
You write to the Claude Code session by its name.
Claude Code leaves its note in the thread.
From @api11:40
Done: the refunds table and POST /refunds, with tests. Next: the payment provider’s webhook.
Codex reads Claude Code’s note, with nothing pasted.
You14:20
To @reviewReplied in 11 min
@review look over the refunds branch.
Codex’s review sits under it.
From @review14:31
Two issues: the refund total rounds per line instead of once, and repeated requests have no idempotency key.
Tue 3 Nov
The next morning, Claude Code starts from the review.
You09:15
@api carry on: fix both.
How to set it up
- Install the ThreadPage plugin in Claude Code and in Codex. Coding agents
- In each session, connect it under a name, such as @api for Claude Code and @review for Codex.
- Keep one thread per project, and write to a session with its @name there.
- Put the rule above in AGENTS.md, so each session reads the thread first and leaves its note before its final reply.
Questions
Which is better, Codex or Claude Code?
This page doesn’t pick one. They differ in where they run, which plan pays for them and which instruction file they read. You can use both on one project, which is what the thread is for.
Can Codex read what Claude Code wrote?
Yes. Both read the files in your repository, and with ThreadPage Pro both read the project’s thread: when you write to a session with @, it reads what your other AIs wrote there.
Do I pay for both?
Yes, if you use both: Claude Code runs on a Claude plan or an Anthropic API account, and Codex on your ChatGPT plan or an OpenAI API key. ThreadPage’s Pro pays for neither.
Can they work on the same repository at once?
Give each its own branch or worktree, so they don’t edit the same files at the same time, and let the thread say who is doing what.
Limits
- Reading the thread and asking a session with @ need ThreadPage Pro with Sync on. On Free and Plus, a session can only add notes to your Inbox.
- A session works on your @ request while it is open on your computer.
- ThreadPage doesn’t record your sessions. A session reads and adds notes through the ThreadPage plugin.
Claude Code, Codex, Claude, ChatGPT, Anthropic, OpenAI, VS Code, and JetBrains are the names of their owners. ThreadPage is independent and not affiliated with or endorsed by them.
Start with one thread.
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Start writingKeep track of multiple Claude Code and Codex sessions
Send work to Claude Code in three repositories and Codex in two. For you shows the session with a question, the one waiting for approval and the replies you haven’t read.
Pro sessions and For youAsk before bed, read the reply at breakfast
Write to @shop before you log off. If it has a question in the night, you see it at breakfast. The reply comes with screenshots.
Pro a session on your computer