Dominik Kundel’s new Codex plugin for Claude Code adds a straightforward bridge between Claude Code and OpenAI Codex: trigger Codex from inside a Claude Code session, delegate work out, and pull results back in—using an existing ChatGPT subscription for access.
The idea isn’t to replace either tool’s “native” experience. It’s more about making multi-agent workflows feel less improvised: Claude Code can keep the main thread of the session while Codex spins on specific tasks or provides a second opinion on changes.
What the plugin actually does
At a high level, the plugin creates a purpose-built interface between Claude Code (CC) and Codex. Kundel describes the flow as Claude passing a task over to Codex, with a Codex agent handling the work and then passing the output back into Claude Code.
Two details stand out for developers who already dabble with agent handoffs:
- The plugin is built on top of the Codex app server, using the same open-source agent harness as the rest of Codex.
- Because it keeps a persistent Codex app server running throughout the Claude Code session, the overhead should be smaller than repeatedly kicking off one-off invocations—and it’s designed to support multiple Codex tasks in parallel in the background.
Kundel also notes that this is different from using a Codex app server MCP connection largely due to a more purpose-built interface between Claude Code and Codex.
A practical use case: review, second opinions, and thorny bugs
When asked what the point is (especially for those who haven’t used Codex much), Kundel pointed to a few motivations that map well to real-world “pairing” habits:
- Codex code review capabilities as a dedicated check on changes
- Using Codex for bugs that Claude Code can’t figure out
- Getting a second opinion without leaving the primary session
- A simple way to try Codex capabilities in an existing workflow
Installation and commands inside Claude Code
Kundel shared a short set of steps that installs the marketplace entry, installs the plugin, and verifies setup:
- Install the plugin in Claude Code:
/plugins marketplace add openai/codex-plugin-cc
/plugins install codex@openai-codex - Reload plugins:
/reload-plugins - Verify setup:
/codex:setup - Delegate or request review:
/codex:review
There’s also an installation link shared in the announcement: https://t.co/u6gBpArwBc
Forks, extensions, and an “open ecosystem” angle
Kundel framed the release as a nod to an open ecosystem: because it rides on the Codex app-server protocol and harness, it naturally invites experimentation—though he cautioned that bringing forks back upstream could get messy due to how tightly it’s built around that protocol.
That said, the plugin’s direction is clear: make it easier to keep Claude Code as the conversational hub, while Codex runs as a parallel worker for targeted tasks and reviews.
Original source: https://x.com/dkundel/status/2038670330257109461
