Wherefore

Close every tab without losing what it was for.

People keep tabs open because each one stands in for an intention: something to finish, follow, decide, read or come back to. Wherefore works out why each tab is open, groups your tabs into those intentions, and saves them, so you can close the tabs and keep the reasons. ("Wherefore" means why: as in "wherefore art thou Romeo".)

Status: early. A working proof of concept lives at the repo root. The product is being rewritten on Effect v4 in packages/. Nothing is published to the Chrome Web Store yet.

How it works

An agent gets your tabs (titles and redacted URLs) and decides on its own when to:

• read_pages: read page text (PR state, product page, article progress)

• wake_and_read_pages: reload sleeping tabs in the background, then read them

• ask_user: ask you about tabs that are still unclear (shown in the side panel)

• submit_intentions: return intentions covering every tab

Finished things (a merged PR, a completed order) and dead tabs (logins, error pages, duplicates) become easy closes. Everything else becomes a saved item (To do, Follow up, Read or Keep) that you can come back to later.

Related MCP server: Agentic Tab Organizer MCP

Try the proof of concept

Requires Node 22+ and pnpm (the version is pinned in package.json).

pnpm install
pnpm build:all        # extension + companion

Chrome → chrome://extensions → Developer mode → Load unpacked → .output/chrome-mv3. Click the toolbar icon to open the side panel and pick a mode.

Three ways to connect a model

MCP and ACP use your existing agent subscription, with no API key.

MCP / ACP setup (once per machine)

pnpm companion:install

This registers the native messaging host for Chrome, Chromium, Brave, Edge and Arc (macOS, Linux, Windows) and prints the MCP command, for example:

claude mcp add --scope user tab-intentions -- /path/to/node /path/to/companion/dist/cli.js mcp

Then in Claude Code run /mcp__tab-intentions__organize-tabs, or just ask it to organize your tabs. Re-run pnpm companion:install if you move the repo or change Node versions (the paths are baked in).

How the pieces talk

API:  side panel ──HTTPS──► Claude API
MCP:  agent ──stdio/MCP──► companion `mcp` ◄──ws://127.0.0.1:17373-17380── extension background
ACP:  side panel ──native messaging──► companion `native-host` ──stdio/ACP──► agent
                                                                    └─ gets companion `mcp` for the tools

• The extension ID is pinned by the public key in wxt.config.ts, so every unpacked install has the same ID (anpbbaiepneaddgoldgmapilgiflochg). The native host manifest and the bridge's origin check rely on it.

• The bridge only accepts WebSocket connections from that extension's origin.

• With several Chrome profiles, each profile's extension connects to the MCP server, and the agent sees all their tabs.

• In ACP mode the agent may only call this project's tools; other tool permission requests are declined.

Privacy

• URL parameters that look like secrets (code, token, sk, …) and very long values are redacted before anything leaves the browser.

• Mail, chat, cloud consoles, API-key, OAuth and localhost pages are never read (lib/tabs.ts → SENSITIVE_HOSTS).

• Tab metadata, and snippets of the pages the agent reads, go to whichever model you connect.

Repository layout

The proof of concept stays as the reference until the rewrite reaches parity, then it is removed.

Development

pnpm install
pnpm typecheck:packages   # rewrite packages
pnpm test:packages
pnpm -C packages/extension build   # rewrite extension (see packages/extension/README.md)
pnpm typecheck            # proof of concept

• Effect packages are pinned to exact versions on purpose; don't add ^ ranges.

• Code in packages/* imports Effect's unstable modules (effect/unstable/*) only from that package's src/unstable.ts.

Contributing

main is protected: every change goes through a pull request, and CI (typecheck, tests, build) must pass. PRs are merged with squash or rebase only, so history stays linear. To report a security issue, use GitHub's private vulnerability reporting (the repo's Security tab), not a public issue.

License

GPL-3.0-or-later