Claude Code vs Codex: use both, and switch when you hit a limit
Many developers now have both Claude Code and Codex. Which model is better changes from month to month, so this page skips that question. What matters for daily work is how each tool reads your project, where it keeps its session, and what happens when its usage window runs out halfway through a task.
Side by side
| Claude Code | Codex | |
|---|---|---|
| Instruction file | CLAUDE.md (a one-line @AGENTS.md import pulls in the shared file) | AGENTS.md |
| Skills folder | .claude/skills/, or plugins | .agents/skills/, invoked as $name |
| Where the session lives | ~/.claude/projects/…/<id>.jsonl | ~/.codex/sessions/… |
| Resume the same session | claude -r <id> | codex resume <id> or codex resume --last |
| Cloud option | Claude Code on the web and Projects threads | Codex cloud tasks |
| Usage | 5-hour and weekly windows on Pro and Max plans | 5-hour and weekly windows on ChatGPT plans |
| Can it read the other's session? | No | No |
The last row is the important one. Neither tool can open the other's transcript, and a second account of the same tool can't either. When one runs out, the plan, the decisions and your uncommitted edits are stuck in a session nothing else can read.
When Claude Code hits its usage limit
The fix is to keep the state of the work in the repository instead of in the chat. With SpecWeave:
-
In Claude Code, say "hand off", or run:
specweave handoff --reason "out of usage"This releases your task claims, writes
handoff.mdwith where you stopped and what comes next, and pushes your branch and a snapshot of your uncommitted edits. -
Open Codex in the same repository and say "pick up", or run:
specweave pickupCodex gets your edits back and sees the next task with its acceptance criteria, any notes, and the project memory, all in one read.
It works the same way in the other direction, and between two accounts of the same tool. See Handoff and pickup for the details.
Hand off before the limit, automatically
On your own machine, SpecWeave can do this for you:
specweave auto-handoff on # hand off at 90% of the 5-hour or weekly window
In Claude Code it reads the usage the status line reports. In Codex it reads the rate limits Codex writes to its session log. When usage crosses the threshold, the agent stops once, runs specweave handoff, and tells you to say "pick up" in the other tool. Cloud sessions don't expose usage, so there you still say "hand off" yourself.
Set up one repository for both
npm install -g specweave
specweave init
init writes one AGENTS.md for Codex and every other agent, a CLAUDE.md that imports it, and the same skills into .claude/skills/ and .agents/skills/. Nothing needs reinstalling when you switch. See AGENTS.md vs CLAUDE.md for why one file is enough.
Using both on purpose
Switching isn't only for emergencies. Some teams let one tool implement and the other review, or run a Claude Code Projects thread and a Codex cloud task on separate increments at the same time. The ledger records which tool claimed and finished each task (claude@laptop, codex@cloud), so you can see afterwards who did what.
Common questions
Can Codex read my Claude Code conversation? No, and no tool can read another's. SpecWeave carries what matters (the spec, the task state, your edits and a note) through git instead.
Do I need both subscriptions? No. The same handoff works between two accounts of one tool, or to Grok Build, Gemini CLI, Cursor or Copilot.
What if I don't want another CLI? Install the self-contained handoff skill with npx vskill i handoff. It needs only git and a shell and writes a compatible handoff.md.