LLM Choir

A single-window "browser-in-a-browser". It shows ChatGPT, Claude, and Gemini side by side, each as a real embedded browser (full login, uploads, voice — every site feature works and sessions persist), with one shared prompt box that asks all three at once.

Why this design

ChatGPT/Claude/Gemini all send X-Frame-Options / frame-ancestors headers that forbid being shown inside another web page, so Streamlit (or any HTML page) cannot embed them in iframes — that's a hard server-side block, not a tooling limit.

This app uses Microsoft Edge WebView2 instead. WebView2 is signed by Microsoft and already built into Windows 11, so — unlike Electron or Playwright's Firefox — antivirus (ALYac) does not block it. No Node, no Electron, no unsigned Chromium, no AV exclusions.

It's a tiny C# WinForms app compiled with the C# compiler that ships inside Windows (csc.exe), so nothing had to be installed.

Run

run.bat

(run.bat builds LLMChoir.exe on first use, then launches it. To rebuild after editing the code, run build.bat.)

Use it

In-app help: click the ? button at the top-right of the tab bar any time for a built-in guide to all the controls and shortcuts.

1. Log in once. All three panels share one sign-in session, so signing into Google in any panel signs you into the others (single sign-on). Sessions are saved per-user under %LOCALAPPDATA%\MultiLLMConsole\profile\ and persist.
   • Gemini uses your Google account; WebView2 presents as Edge, which Google accepts. Each service still needs a one-time "Sign in with Google" click, but you won't re-enter your password/2FA once Google is signed in anywhere.
   • This is the same as being logged into several sites in one normal browser — the browser still isolates each site's own cookies by domain; only the shared Google session is reused.
2. Type a prompt in the box at the bottom of the window and press Enter to send it to all three (use Shift+Enter for a line break), or click Send to all.
3. Controls (in the bottom bar): two rows of per-service checkboxes — Send: chooses which LLMs receive the prompt, and Show: shows/hides each LLM's panel (independent of Send, so you can keep sending to an LLM while hiding its window; visible panels expand to fill the freed space). Plus Fill only (stage text without sending), Attach to all (pick file(s) once and upload them to every enabled panel at once), New chat (all), and per-panel reload (↻).
   • Attach to all opens one file picker and drops the chosen file(s) onto each site's own uploader, so the attachment appears in all three composers. Then type your prompt and Send to all as usual. No native dialog pops per panel — it uses WebView2's DevTools protocol (DOM.setFileInputFiles), the same mechanism browser-automation tools use.
4. Tabs: the bar at the very top holds comparison tabs. Click + to open another independent 3-panel comparison, click a tab to switch, and × to close one. Every tab shares the same login (one profile), but each has its own prompt box and its own ChatGPT/Claude/Gemini chats — like separate browser tabs. Note: each tab runs three browser panels, so many open tabs use more memory, just like a real browser.
   • Shortcuts: Ctrl+T new tab, Ctrl+W close the current tab, middle-click a tab to close it. (Closing the last tab opens a fresh one.)
   • A tab is named after the first message you send in it (trimmed with …).

Files

• MultiLLM.cs — the whole app (window, three WebView2 panels, broadcast logic).
• app.manifest — DPI awareness + Windows 10/11 declaration.
• Microsoft.Web.WebView2.*.dll + WebView2Loader.dll — WebView2 SDK (from NuGet); these must sit next to the exe so .NET can load them at runtime.
• build.bat / run.bat — compile and launch.
• Login/session data is not kept in this folder — it lives in one shared profile at %LOCALAPPDATA%\MultiLLMConsole\profile\ (per-user, outside the project), so zipping or copying this folder never includes your logins.

Requirements

• Windows 10/11 with the Edge WebView2 Runtime (preinstalled on Win11; on older Win10, install the free "Evergreen" runtime from Microsoft).
• The built-in .NET Framework C# compiler (present on all Windows).

Sharing it (e.g. via GitHub)

This folder is self-contained and safe to share:

1. Anyone on Windows clones/downloads it and runs run.bat. It builds the app with Windows' built-in C# compiler (no install) and launches.
2. Logins are not shared. They live in each user's own %LOCALAPPDATA%\MultiLLMConsole\profile\, outside this folder — so your sessions never travel with the code. Each user simply logs into their own accounts on first run, and it's remembered on their machine only.

The compiled .exe and crash.log are git-ignored, and the per-user profile lives outside the project entirely; the WebView2 SDK DLLs are included so it builds out-of-the-box.

Tuning

If a site changes its page and the prompt stops landing in the box, update that site's InputSelectors / SendSelectors in MultiLLM.cs and run build.bat. Attach to all uploads in two ways. For sites with a standing hidden <input type=file> (ChatGPT/Claude) it injects the files straight into it via the DevTools protocol — instant. Gemini has no such input (it only creates one mid-upload, behind a native dialog), so the app intercepts that dialog and drives Gemini's own uploader: it tries to open it automatically, and if its heuristics miss, the interception stays armed for ~45 s so you can click Gemini's own "＋ ▸ Upload files" and the files are filled in automatically — no OS dialog appears either way. The Gemini panel shows a hint (click + ▸ Upload in Gemini) while it waits. If a site stops accepting attachments after a redesign, adjust its FileInputSelectors in MultiLLM.cs and rebuild.

Troubleshooting

• Self-healing: on startup the app automatically clears any of its own leftover msedgewebview2 processes (from a previous crash/kill) that would otherwise lock the shared profile, and it won't launch a second clashing copy — running run.bat again just brings the existing window to the front. So "double-clicked run.bat and nothing happened" should no longer occur.
• If a launch ever fails silently: check crash.log in this folder for the error.
• Logins: all panels share one signed-in session at %LOCALAPPDATA%\MultiLLMConsole\profile\ (outside this project). Delete that folder to sign out of everything and start fresh.