Codex Plugin for Claude Code: Choose, Install, and Run a Reliable Two-Agent Workflow
The codex-plugin-cc is OpenAI's official plugin enabling Codex to operate as a guest agent within Claude Code, supporting review loops, task delegation, and session transfer Host selection is critical: Claude Code as host uses OpenAI's plugin path, while Codex as host uses Sendbird's reverse plugin—commands and marketplace registries differ and are not interchangeable Project configuration requires separating user-level settings (~/.codex/config.toml) from trusted-project overrides (.codex/confi
Analysis
TL;DR
- The codex-plugin-cc is OpenAI's official plugin enabling Codex to operate as a guest agent within Claude Code, supporting review loops, task delegation, and session transfer
- Host selection is critical: Claude Code as host uses OpenAI's plugin path, while Codex as host uses Sendbird's reverse plugin—commands and marketplace registries differ and are not interchangeable
- Project configuration requires separating user-level settings (~/.codex/config.toml) from trusted-project overrides (.codex/config.toml), with trust flags controlling whether local overrides load
- Shared instruction files (AGENTS.md and CLAUDE.md) must be synchronized via symlinks or a pointer strategy to prevent agent drift on conventions, lint rules, and test commands
- Approval policies and sandbox modes (untrusted/workspace-write vs danger-full-access) must be matched to task risk level, with model reasoning effort treated as a token-cost decision rather than a free quality boost
Why It Matters
This article addresses a growing operational pattern in AI-assisted development: running multiple LLM agents in concert on the same codebase. As practitioners adopt dual-agent workflows, the lack of clear host/guest boundaries and instruction synchronization leads to wasted time, configuration drift, and conflicting code conventions. Understanding the wiring mechanics prevents setup failures and enables scalable multi-agent collaboration.
Technical Details
- Plugin installation: Four slash commands in Claude Code—
/plugin marketplace add openai/codex-plugin-cc,/plugin install codex@openai-codex,/reload-plugins,/codex:setup—with Node.js 18.18+ required and separate authentication for both ChatGPT/Codex and Claude Code - Reverse path: Sendbird's cc-plugin-codex inverts the relationship, running Claude Code as a guest inside Codex via
codex plugin marketplace add sendbird/codex-marketplaceandcodex plugin add cc@sendbird, with idempotent setup throughnpx cc-plugin-codex install - Configuration hierarchy: User defaults in
~/.codex/config.tomlapply globally; trusted-project overrides in.codex/config.tomlat the repo root only load when the directory is marked trusted, with keys likemodel,model_reasoning_effort,approval_policy, andsandbox_mode - Instruction file strategy: AGENTS.md serves as Codex's project doc; CLAUDE.md serves Claude Code's. Recommended patterns include symlinking (
ln -s AGENTS.md CLAUDE.md) for identical rules or maintaining a pointer in CLAUDE.md with tool-specific additions kept separate - Sandbox and approval controls:
approval_policyvalues includeuntrustedandon-request;sandbox_modeincludesread-only,workspace-write, anddanger-full-access; CLI flags--auto-editand--full-autofurther control prompting behavior independently of config
Industry Insight
- Multi-agent coding workflows will become standard, but the host/guest architecture decision must be made before installation—mixing plugin paths creates silent failures that waste debugging time
- Instruction file synchronization is the hidden bottleneck in multi-agent projects; teams should adopt a single-source-of-truth policy (symlink or pointer) as a project onboarding requirement, not an afterthought
- Token-cost awareness around
model_reasoning_effortsettings will become a cost-optimization lever as multi-agent loops scale; leaving high reasoning effort on by default across review cycles can significantly inflate API spend
Disclaimer: The above content is generated by AI and is for reference only.