Myrlin Workbook

Every Claude Code and Codex session on your machine, in one sidebar.

Myrlin Workbook reads the session files Claude Code and the ChatGPT app already write to your disk, then puts live terminals, search, cost and project docs on top of them.

$ npx myrlin-workbook@alpha
Read the source

Node 20 or newer, on Windows, macOS or Linux. The stable line is npx myrlin-workbook.

Myrlin Workbook / Workbench recorded from the running app
A tour of the app: the project sidebar, a session opening into a terminal pane, scrollback being selected, a Codex session, the phone layout and the cost panel.
Thirty seconds, no narration. Watch the tour
Two tools, one list
Claude Code sessions come from ~/.claude/projects, Codex sessions from ~/.codex and the SQLite file the ChatGPT app itself reads. The folders and titles match the ones you see there.
See which one is waiting
A running session is a filled mark. A session waiting on your input is a ring. The shape carries the state, so nothing has to blink to get your attention.
Terminals in the page
xterm.js over node-pty, so a session runs in front of you instead of in a window you lost. Windows drives ConPTY directly. There is no WSL step.
Nothing leaves the machine
No account, no server of ours, no telemetry. The app binds to 127.0.0.1; reaching it from your phone is something you turn on, behind a password.
What it does

Built around the files your tools already write.

Nothing here asks you to change how you work. The app reads what Claude Code and Codex leave on disk, and adds the parts they do not have.

01 / Sidebar

One sidebar for two tools

Projects down the left, a Recent list above them, and a provider switcher in the Discovered header that filters that list to Claude or to Codex. Sessions group under the working directory they ran in, so a project row is a folder you recognise.

  • Recent merges both providers, newest first
  • Double click a session to rename it; drag it onto another project to move it
  • Hidden sessions stay out of the way until you ask for them
The sidebar: the provider switcher in the Discovered header, the Recent list, and project rows expanding into sessions.
Discovery, the Recent list and the provider switcher.
02 / Terminal

A terminal you can actually scroll back through and copy from

Agent CLIs paint into the alternate screen buffer and never scroll, so there is no terminal scrollback to reach, here or in any other terminal. The scrollback surface goes to where the history actually lives: the terminal's own ring and a server-side line log for a shell, the transcript on disk for an agent. The live screen is the last segment of that one document, so a drag from the bottom to any point above it selects a continuous range.

  • Wheel up past the top of the screen and keep going
  • Drag-select across the whole document and copy it
  • Panes tile two or four up, and each keeps its own history
A terminal pane with live output, scrolled back through earlier history, with a selection dragged across it and copied.
Live output, then a wheel back through history and one selection across it.
03 / Themes

Thirteen terminal palettes, and chrome that can follow the system

The chrome has a light setting, a dark setting and a system default. The terminal carries thirteen palettes of its own, and every one is derived from the same tokens as the chrome, so changing one cannot leave the other behind.

  • Mocha, Macchiato, Frappe, Nord, Dracula, Tokyo Night, Cherry, Ocean, Amber, Mint
  • Light palettes too: Latte, Rose Pine Dawn, Gruvbox Light
The app in light chrome and then dark chrome, followed by four terminal palettes applied in turn.
Light and dark chrome, then four of the terminal palettes.
04 / Cost and plan

What it cost, and what is next

Cost comes out of the transcripts the providers already write: input, output, cache writes and cache reads, priced per model where a price is published (Codex shows its token counts and no invented dollar figure), per session and per project. Alongside it, each project carries a kanban board and its own Notes, Goals, Tasks and Rules, so the plan lives with the code rather than in another tool.

  • Cards drag between columns and stay with the project
  • Docs are plain markdown on disk, editable in the page
The cost panel with per-session totals, then the kanban board with a card being dragged between columns.
The cost panel, then the board with a card in flight.

Search

One query across both providers, answered with snippets and timestamps rather than a list of file names.

Templates

Save a session's model, flags and working directory, then launch that setup again without retyping it.

Conflicts

A warning when two live sessions have touched the same file, before the two sets of edits meet.

Recovery

Sessions are checked against their process on startup, so a crash or a reboot does not lose the map of what was running.

05 / Phone

Your sessions, on your phone, over your own tunnel.

The phone layout is the same application, not a read-only viewer. Five tabs across the bottom: Home, Sessions, Terminal, Attention and Search. Terminals are real terminals, with a layout that moves for the keyboard and long-press menus where a right click would be.

  • Bind to your LAN address with CWM_HOST, or point a Cloudflare tunnel at it
  • Installable to the home screen, so it opens without browser chrome
  • Reachable only behind the password you set
The phone layout: the five tab bar, a session opening, the keyboard rising under a terminal, and a long-press menu.
06 / Codex

Codex sessions, the way the ChatGPT app shows them

Codex writes its rollouts to ~/.codex, but the folder names and session titles the ChatGPT desktop app displays come from a SQLite database sitting beside them. This app opens that database read-only and watches it for changes, so a project here is the project you see there, under the same name.

A session's model, sandbox, approval mode and reasoning effort are read from the conversation itself. When a value was never set, it says so instead of filling in a default that nothing is running.

Every session carries its provider: Claude Codex
Codex project folders and sessions listed as the ChatGPT app names them, with the session detail strip showing model, effort, approval and sandbox.
Codex projects and sessions, and the detail strip for one of them.
Licence

Open source. Runs locally. Windows, macOS, Linux.

There is no hosted version to sign up for and no paid tier holding a feature back. What is in the repository is what you run.

AGPL-3.0

The whole application, this page included. Fork it, run it, change it, ship your changes under the same licence.

No account

Nothing to sign up for. The app talks to your disk and to the CLIs you have already installed.

Local by default

It binds to 127.0.0.1. Opening it to your network is a deliberate step, and it takes a password with it.

Every platform the CLIs run on

Windows natively, without WSL, plus macOS and Linux. The only requirement is Node 20 or newer.

GitHub stars for therealarthur/myrlin-workbook Current version of myrlin-workbook on npm
Get it

Two lines, depending on which one you want.

Both run straight from npm. Neither installs anything globally, and neither asks you to create anything.

Alpha, the 1.3 line

recommended

Both providers, the redesigned interface, the phone layout and the scrollback surface. This is where the work is happening.

$ npx myrlin-workbook@alpha

Stable, the 0.9 line

Claude only

The settled release. Claude Code sessions only, and the interface as it was before the redesign.

$ npx myrlin-workbook

It starts on http://127.0.0.1:3456 and opens your browser. Node 20 or newer.