The problem
If you pay for both Claude and ChatGPT plans, every new task starts with a small decision. Most of the time it isn't about which model is smarter; it's practical: which plan still has room this afternoon, which app already knows this repo, and whether this job will burn through what's left of a 5-hour window.
Answering that means opening two usage pages and remembering where you worked yesterday. So people default to one app, hit its limit mid-task, and switch in a hurry.
How Pairbar solves it
- Open the composerPress ✎ in the header, or + on a project's group header. The header reads Claude | Codex.
- Check the green dotIt marks the suggested app for this folder, right now.
- Press ⓘ for the reasoningIt explains why that app is suggested and shows how much of each plan's limit is left.
- Accept it or override itKeep the suggestion, or click the other app. Your choice for this chat is yours; the suggestion is only a starting point.
- Make it permanent if you preferIn Settings → Chats & sidebar → Start new chats in, choose suggest (the default), always Claude, or always Codex.
What the suggestion looks at
| Signal | What it means |
|---|---|
| Limit headroom | how much of each plan's tightest limit (the 5-hour or the weekly window, whichever is fuller) is left |
| History | where you've been working in this project recently |
| Cost | a typical chat's share of the limit; an app without enough left for a typical chat isn't suggested |
Claude's numbers come from Claude Code's status line (set up by Install of live status for Claude) or the Claude app's own record, with claude -p /usage only as a last resort; Codex's from the newest rate-limit report in its local session files. See limits.
Practical differences inside Pairbar
Beyond limits, a few Pairbar features behave differently per app, which can matter when you choose:
| Need | Claude | Codex |
|---|---|---|
| Start in the cloud from Pairbar | opens Claude with your text; you pick a cloud environment and send there | sent straight to Codex Cloud when an environment id is saved for the repo |
| Send a follow-up while it's working | only once the chat isn't working | queued even mid-turn |
| Set reasoning effort from the composer | set it in Claude (the app resets effort when it opens a chat) | yes, Faster ↔ Smarter slider |
| Start with one of your agents | @agent-… | the agent's instructions up front |
| Rename so the app shows it | Pairbar only | renamed in Codex too |
Workflows use the same idea: the Plan with chip defaults to the app with more of its limit left, and the planner gives heavier steps to that app.
Without Pairbar
Without Pairbar, people usually decide by:
- Checking each usage page (Claude's own usage page, and the usage information Codex shows; see OpenAI's docs for where) before starting.
- A fixed rule of thumb, such as one app for exploration and the other for long unattended runs.
- Sticking with one app until it hits a limit, then moving the work with a manual summary.
Frequently asked questions
- Does Pairbar decide which model is better for my task?
- No. It suggests an app from your remaining plan limits, where you've worked in the project recently and a typical chat's cost. It doesn't read your message or rank models.
- Can I turn the suggestion off?
- Yes. Settings → Chats & sidebar → Start new chats in can be set to always Claude or always Codex instead of suggest.
- Why wasn't the app I usually use suggested?
- Probably because its tightest limit doesn't have enough left for a typical chat. Press ⓘ in the composer to see the reason and each plan's remaining limit.
- What if I only have one of the apps?
- Pairbar shows only the app you have, so new chats start there.
Related
- DocsNew chatsThe composer: app, folder, branch, worktree, agent, skills, model, effort, mode, cloud; searchable pickers, remembered choices, and the Claude-or-Codex suggestion
- Use caseKeep an eye on your Claude and Codex plan limits while you workUsage rings for both plans, a limits card with each window's reset time, and limit-aware chat suggestions and workflows.
- Use caseSwitch between Claude Code and Codex on a Mac without hunting for windowsOne list for both apps; clicking a chat from the other app swaps its window into the same spot.
- GlossaryPlan usage limitsThe caps a Claude or ChatGPT subscription puts on Claude Code and Codex use, measured over a five-hour window and a weekly window.
- Glossary5-hour usage windowClaude's session limit: a five-hour period after which your session allowance resets, shared by claude.ai, Claude Code and Claude Desktop.
- Use caseGet a second opinion from Codex without leaving your Claude Code chatA Claude chat asks Pairbar for a second opinion; after you approve, a read-only Codex chat answers and the reply comes back into the Claude chat.
Try Pairbar free for 7 days
One sidebar for the Claude and Codex desktop apps. Everything on for 7 days, no card needed; then $49/year ($39 first year with LAUNCH), $9/month or $129 lifetime (first 200 buyers). macOS 26 or later, Apple silicon.