commongrounds

Sync · Version · Attribute

Your files.
Your agents.
One history.

A shared folder that syncs like Drive, versions like Git, and records which change was made by a person and which by an AI agent — and how sure it is.

Create an account See how it works

1 GiB per account once you confirm your address. Works with every agent that writes to the folder; hooks and MCP for Claude Code, Cursor and Codex, MCP for Gemini and Claude Desktop.

history · main
  1. agent session claude-code declared 2m ago

    claude-code claimed it via Edit

    src/auth.rs
  2. auto claude-code inferred 4m ago

    changed during a session, unclaimed

    src/main.rs
  3. auto ada · laptop human 1h ago

    baseline

    README.md · config.toml

Every entry says how it knows. An agent that didn't announce its edit is recorded as inferred, never credited.

Syncs like Drive

Save a file and it's everywhere. Content-defined chunking means appending a megabyte to a 100 MB file uploads two chunks, not the file.

Versions like Git

Every synced state is a snapshot. Edits to different lines merge cleanly; edits to the same line keep both versions, side by side, never silently.

Attributes like nothing else

Which change was a person's and which was an agent's. Recorded with a confidence level, because a history that confidently mislabels your careful edit as AI output is worse than one that admits it doesn't know.

Set it up once, then work the way you already do

CommonGrounds is a folder. Everything that edits files in it takes part — your editor, your terminal and every AI agent on your machine — with no integration to write and nothing to port. Agents that announce themselves get credited precisely; the rest are still versioned, still synced, and recorded as what they are.

1

Open the app and sign in

Download the single file below and double-click it. Sign in, choose a folder, and it starts syncing. It also starts when you log in, so your folders stay current with the window closed.

2

Share it by email

Type a colleague’s address. They accept or decline; accepting puts the folder on their machine and charges it to your quota, not theirs. Their edits reach you in seconds, and yours reach them the same way.

3

Let the agents introduce themselves

cg agent setup

Once, inside the folder. It configures the agents already used there and nothing else. What it writes names a command to run, so it stays on this machine and never syncs to anybody.

What each client gives you

The same folder, seen from wherever you work.

Desktop app

Windows · macOS · Linux

Sign in, add folders, watch them arrive. It shows whose workspace each one is, what changed and when, and which invitations are waiting for an answer.

It is also what agents talk to: the app serves a local socket for every folder it manages, which is what makes step 3 work at all.

Command line

the same file 
cg status
cg log --files
cg cat --revision <id> plan.md
cg memory add "the staging bucket is the one to use"

Double-click the download and a window opens; run it from a terminal and it is a command-line tool. Nothing separate to install.

Claude Code

hooks & MCP

cg agent setup writes an MCP server and hooks into .mcp.json and .claude/settings.local.json.

Claude then reads and writes through cg_read, cg_write and cg_edit, and every change is recorded as certainly its own. A write that would replace a file changed since it was read is refused rather than performed, so a colleague’s paragraph cannot vanish under it.

Codex CLI

hooks & MCP

OpenAI’s coding agent, set up through .codex/config.toml and .codex/hooks.json. Same tools, same certainty about who changed what.

Codex reads AGENTS.md natively, and that is the file the folder uses to explain itself — what the workspace is, that it changes under you, and where the team’s shared memory lives.

ChatGPT in a browser cannot reach your files, so it is Codex on your own machine that takes part here.

Cursor

hooks & MCP

Through .cursor/mcp.json and .cursor/hooks.json. Same tools, same certainty about who changed what.

Gemini CLI

MCP, no hooks

cg agent setup writes the MCP server into .gemini/settings.json, so Gemini gets cg_read, cg_write and cg_edit with the same certainty and the same refusal to overwrite a file that moved under it.

It also reads GEMINI.md, where CommonGrounds keeps the block pointing at the workspace’s shared memory.

Hooks are deliberately not written. They are where the vendors differ most, and a hook that half works claims one agent’s edit for another. Anything Gemini changes with its own tools is attributed by inference, as it would be anyway.

Anything else

no setup

Copilot, an editor, a build script, a colleague on a laptop with none of this installed. Whatever writes to the folder is picked up, chunked, versioned and synced.

The history says found on disk, nobody claimed it, which is the honest answer and the point: a tool that guessed would eventually credit your careful work to a machine.

Everything else in the box

The folder is the product; this is what sits around it once a second person, or a second agent, is in there with you.

Reviews for what an agent proposes

branches

An agent session can work on a proposal branch instead of your main line. When it ends, a review opens: read the diff, comment, approve or reject. In an organisation’s folder that is the default, so nothing a model wrote arrives unseen.

Share by address, or by link

owner, editor, viewer

Invite a colleague by email and they accept or decline. Or make a share link at viewer or editor, for a day or until you stop it, and let a group let themselves in.

Download links for people with no account

zip

Hand a client, an auditor or a printer the folder — or one folder inside it — as a zip, written while it is sent. Always expires, can need a passphrase, can be limited to a number of downloads, and can be stopped.

Right-click a folder in Explorer

Windows

Sync with CommonGrounds on a folder, Generate download link with CommonGrounds on a folder or a file. The app opens on the right form with the path already in it.

Memory that stays

team & personal

What the people and agents here have learned is kept in the folder, where the next session reads it. What you have learned follows your account to every machine you sign in on.

Organisations, teams, and a record

for a company

Folders that belong to the company rather than to a person, teams invited at once, policy that says what an agent may do in a folder — and an audit ledger of what each session was allowed and what it did.

Get the client

One binary, no installer, no runtime. Double-click it and a window opens; run it from a terminal and it is a command-line tool. Same file either way.

Looking up the builds…