Pair

Claude Code and OpenAI Codex, working together in a native macOS app.
_{macOS 14 (Sonoma) or later · Apple Silicon}

Download · How it Works · Install

---

Pair runs Claude Code in a managed terminal and lets Codex review its work every time it pauses. If the task isn't done, Codex sends feedback directly into Claude's input. If Claude asks a question, Codex answers it. Both models keep going until the job is actually finished.

No clipboard hacks, no accessibility permissions. Codex types into the terminal through the PTY it owns.

How It Works

sequenceDiagram
    participant User
    participant PairApp
    participant Claude as Claude Code
    participant Hook as Hook Handler
    participant Codex as Codex CLI

    User->>PairApp: Select project directory
    PairApp->>Claude: Launch in managed PTY
    Claude->>Claude: Work on task...
    Claude-->>Hook: Stop hook fires
    Hook->>Hook: Parse transcript + git diff
    Hook->>Codex: Review prompt (read-only)
    Codex-->>Hook: APPROVE / FEEDBACK / CONTEXT
    alt FEEDBACK
        Hook->>PairApp: send_input via IPC
        PairApp->>Claude: Type feedback into PTY
        Claude->>Claude: Continue working...
    else APPROVE
        Hook-->>Claude: Allow stop
    end

Loading

graph LR
    subgraph PairApp [Native macOS App]
        Terminal[Claude Terminal<br/>SwiftTerm PTY]
        Panel[Codex Review Panel<br/>SwiftUI]
        IPC[Unix Socket IPC]
    end

    subgraph Hooks [Claude Code Hooks]
        Stop[Stop Hook]
        Perm[Permission Hook]
    end

    subgraph External
        CodexCLI[Codex CLI<br/>read-only]
        Transcript[Session Transcript<br/>JSONL]
        Rules[rules.md<br/>Shared Brain]
    end

    Stop -->|stdin JSON| IPC
    IPC -->|send_input| Terminal
    IPC -->|read_screen| Panel
    Stop --> CodexCLI
    CodexCLI --> Rules
    Stop --> Transcript
    Perm -->|approve/deny| CodexCLI

Loading

Features

• Split-pane window. Claude Code on the left, Codex review panel on the right.
• Completion gate. Codex reviews when Claude pauses. Blocks until the task is done, not just reported as done.
• Direct PTY input. Codex types into Claude's terminal. No clipboard, no System Events, no focus stealing.
• Multi-session tabs. Run several Claude sessions at once. ⌘1-9 to switch.
• Project picker. Scans ~/git for repos. Shows recent projects with timestamps.
• Auth check. Verifies Claude and Codex are authenticated before starting. Supports API keys and subscriptions.
• Themes. Ships with a dark emerald theme. Also reads your Ghostty config for colors and fonts. ⌘T to toggle.
• Departure Mono. Pixel-retro terminal typography across the UI.
• Scratchpad. Write multi-line prompts before sending. Enter makes new lines, not submissions.
• Screen reading. Codex can read what Claude is displaying as plain text, without relying on transcripts.
• Shell integration. Injects session IDs and socket paths into your shell via the ZDOTDIR trick.
• Shared rules. Both models read a rules.md file you can edit to steer reviews.
• GhosttyKit ready. The Metal GPU rendering framework is built. Optional upgrade from SwiftTerm.

Prerequisites

• macOS 14+
• Claude Code, installed and authenticated
• Codex CLI, installed and authenticated
• Node.js 22+

Install

Build from source (recommended)

git clone https://github.com/ytspar/claude-codex-pair
cd claude-codex-pair/app/PairApp
swift build -c release
# Run:
.build/release/PairApp

Pre-built binary

Download from Releases. The binary is ad-hoc signed but not Apple-notarized, so macOS will block it. To allow it:

xattr -cr Pair.app
open Pair.app

CLI tools (optional)

cd claude-codex-pair
npm install && npm run build && npm link

This gives you pair start, pair stop, pair status, pair review, pair report, and pair config in the terminal.

Usage

Open the app. It checks auth, you pick a project, Claude starts working with Codex watching.

Shortcut	Action
⌘N	New session
⌘W	Close session
⌘1-9	Switch sessions
⌘T	Toggle theme
⌘⇧W	Close window

From the CLI

pair launch ~/my-project    # Open Pair with a Claude session
pair start                  # TUI monitor for all sessions
pair review                 # One-shot Codex review of current diff
pair report                 # Markdown report of interactions

Configuration

Stored at ~/.claude-codex-pair/config.json.

Key	Default	What it does
maxCycles	5	Review cycles before auto-approve
codexModel	null	Override Codex model
codexTimeout	300000	Codex call timeout (ms)
logDir	~/.claude-codex-pair/sessions	Where session logs go
targetSessions	null	Limit reviews to specific projects

Architecture

app/PairApp/              Native macOS app (Swift, SwiftUI, SwiftTerm)
├── PairWindowView        Split layout: terminal + Codex panel
├── SessionManager        Multi-session PTY management
├── CodexPanelView        Review status, feedback, history
├── ScratchpadView        Draft prompts before sending
├── IPCServer             Unix socket (send_input, read_screen, send_key)
├── AuthChecker           Claude + Codex auth verification
├── ThemeManager          Devbar / Ghostty color switching
├── GhosttyConfig         Parse ~/.config/ghostty/config
├── ShellIntegration      ZDOTDIR trick for zsh
└── GhosttyBridge         Optional Metal GPU rendering

src/                      Node.js hook system
├── monitor/
│   ├── hook-handler      Stop hook: Codex review, feedback loop
│   ├── permission-handler Codex-gated tool approval
│   └── transcript        Parse Claude JSONL transcripts
├── codex/
│   ├── client            Spawn codex exec with streaming
│   └── prompt-builder    Review + respond prompts
└── shared/
    ├── pair-terminal     IPC client for PairApp
    └── rules.md          Shared alignment file

Safety

• Read-only Codex. Always runs with -s read-only. Cannot modify files.
• Cycle limit. Defaults to 5. Prevents infinite feedback loops.
• Graceful fallback. If Codex errors out, Claude continues. Never blocks.
• Socket locked down. IPC restricted to current user (0600 permissions).
• No telemetry. No analytics, no tracking, no network calls except Claude and Codex.

License

MIT. Copyright (c) 2026 Yury Tsukerman.