Calyx MCP
Native macOS terminal with an MCP server and CLI: agents see panes, commands and output, and you grant permissions in one window
- 358 ★ on the repository
- Last commit
- MIT
Broad access
Why this level
- Through MCP agents gain terminal panes: command output, command input and keystrokes, and auto-approve removes the confirmation
- The app edits the configs of Claude Code, Codex, OpenCode, Hermes and Grok, and with Usage Tracking also ~/.claude/settings.json
- The built-in browser runs JavaScript on pages at an agent's command
Install
- Works in
Manual install
brew install --cask calyxNeeds Apple Silicon and macOS 26 Tahoe or later. brew upgrade updates it.
Access and checks
How we reviewBroad accessThe tool can change data, run commands or handle secrets.
- Through MCP agents gain terminal panes: command output, command input and keystrokes, and auto-approve removes the confirmation
- The app edits the configs of Claude Code, Codex, OpenCode, Hermes and Grok, and with Usage Tracking also ~/.claude/settings.json
- The built-in browser runs JavaScript on pages at an agent's command
This is third-party code. Review the repository files before installing.
What it does
Calyx is a native macOS terminal built on the Ghostty engine for running several agents at once: Claude Code, Codex, OpenCode, Hermes, Grok and pi. A sidebar shows each agent's state (working, blocked, idle, done) and expands subagents as child rows. Permission requests from Claude Code and Codex gather in one window in the top-right corner of the screen, where you pick an answer without paging through tabs. For the agents themselves Calyx runs a built-in MCP server. It exposes the list of panes and tabs, a command log with exit codes and captured output (known secret patterns are redacted), messaging between agents in different panes, and language server calls: lsp_hover, lsp_definition, lsp_references, lsp_rename, lsp_diagnostics. The Enable AI Agent IPC switch in settings turns it on, after which Calyx writes calyx-ipc and calyx-mcp blocks into the configs of Claude Code, Codex, OpenCode, Hermes and Grok. The bundle includes the calyx utility: 25 calyx browser commands drive tabs of the built-in browser (accessibility snapshot, click, fill, JavaScript evaluation, screenshot). Comments on diff lines are sent straight to the agent's pane.
Who it is for. Developers on an Apple Silicon Mac who keep several agents in parallel sessions and are tired of hunting for the tab with a permission request.
Good fit when
- Three or four agents work in separate tabs and you need to see at once which one is waiting for you
- Claude Code and Codex permissions are easier to clear as a queue in one window than by hunting for each tab
- An agent reads the output of a neighboring pane or waits for a long command to finish without sleep or manual copying
- An agent's edits are reviewed line by line and the comments go to its pane in one submission
- Browser checks are handed to the agent through calyx browser: page snapshot, click, fill
Not a fit when
- The Mac runs an Intel chip or macOS older than 26: Calyx requires macOS 26 Tahoe and Apple Silicon (arm64)
- You work on Linux or Windows: the app ships for macOS only
- Agents must stay under strict control: with auto-approve on, commands and keystrokes in panes run without confirmation
- You want only the MCP server without a terminal: the README describes no standalone server
Example request
Run the tests in the neighboring pane, wait for them to finish and show the output of the failuresMCP
- Transport
- http
- Authentication
- not required
Limitations
The app runs only on macOS 26 Tahoe and later, on Apple Silicon (arm64). The MCP server is built into the terminal and is not installed separately. Blocks appear in agent configs after Enable AI Agent IPC is switched on, and agents that are already running pick them up only after a restart. pi has no permission prompts of its own, so with the integration off its tool calls run unreviewed. Claude Code token counting covers only sessions started while Usage Tracking is on and adds telemetry settings to ~/.claude/settings.json.
How to disable. Turn off Enable AI Agent IPC in the Agents settings: Calyx stops running the MCP server and writing itself into agent configs, and the telemetry settings it added for Claude Code are removed. If the calyx-ipc and calyx-mcp blocks remain in ~/.claude.json or ~/.codex/config.toml, delete them by hand. The app is removed like any other on macOS; for a Homebrew install brew uninstall --cask calyx works.
FAQ
How do I connect an agent to the Calyx MCP server?
Open Settings, the Agents section, switch on Enable AI Agent IPC and restart the agent. Calyx writes calyx-ipc and calyx-mcp into the config of Claude Code, Codex, OpenCode, Hermes or Grok, whichever it finds on the machine. For pi it installs an extension at ~/.pi/agent/extensions/calyx.ts.
Which agents are supported?
Claude Code, Codex, OpenCode, Hermes, Grok and pi. The approval queue collects Claude Code and Codex requests, Grok calls in always-approve mode and every tool call in pi.
Can agents type commands into my panes?
Yes, through the Agent Cockpit tools. Commands and keystrokes wait for your confirmation by default until you turn on auto-approve.
How does Calyx keep sessions?
Persistent sessions are opt-in: terminals in a background daemon survive quitting the app and crashes, and the Session Browser shows why a kill failed. The calyx-session utility is deployed once to an SSH host, and remote sessions can be reattached.
What does Mission Map show?
Cmd+Shift+M lays out every pane of the window as tiles: agent state, working directory, Git branch, current tool, subagents and a pending permission with an Allow button.
Discussion
No questions or reviews yet.
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Comparison with similar tools
Cards that share the main search query, and how they differ.
| Tool | Official | Authentication | Repository stars | Main difference |
|---|---|---|---|---|
| Calyx (this card) | no | not required | 358 | |
| cmux | no | 28,707 | also a macOS terminal on Ghostty, while Calyx adds a shared permission window and a built-in MCP server with a command log and language servers | |
| Agent Deck | no | 1,216 | a terminal session manager, while Calyx is itself a terminal app for macOS |
README in short
The page opens with a demo and install through Homebrew or an archive, then explains four ideas: agent status, a shared permission list, diff review and a terminal agents can understand. It goes on to the feature list, keyboard shortcuts, details of messaging between panes, the language server proxy, browser commands and known limitations.