browser-cli/README.md

# browser-cli

Control your real, running browser from the terminal or a Python script — no headless browser, no Playwright, no virtual display. Your actual open tabs, windows, and tab groups respond to your commands.

---

## What it does

You have 40 tabs open. You want to close all the duplicates, group the GitHub ones, save your session before a meeting, and open a few URLs into a specific group — all from a script. That is what browser-cli is for.

It works by pairing a small Chrome/Brave extension with a Python CLI tool. The extension has full access to your browser's tabs, windows, groups, and page DOM. The CLI talks to it in real time over a local socket.

---

## How it works

```
terminal / python script
        │
        │  Unix socket  (/tmp/browser-cli.sock)
        ▼
  Native Messaging Host  (Python process, launched by the browser)
        │
        │  Native Messaging Protocol  (stdin/stdout, 4-byte length prefix + JSON)
        ▼
  Chrome Extension  (background service worker)
        │
        │  chrome.* APIs
        ▼
  Your running browser
```

1. The extension calls `chrome.runtime.connectNative('com.browsercli.host')` on startup.
2. The browser launches the native host Python process (registered in the OS).
3. The native host opens a Unix socket at `/tmp/browser-cli.sock`.
4. CLI commands connect to that socket, send a JSON command, and wait for the result.
5. The native host relays the command to the extension via stdout, receives the result via stdin, and sends it back to the CLI.

No server needs to be running beforehand. The browser manages the native host's lifecycle.

**Message format**

Every command is a JSON object:
```json
{ "id": "uuid", "command": "tabs.list", "args": {} }
```
Every response:
```json
{ "id": "uuid", "success": true, "data": [...] }
```

---

## Installation

**Requirements:** Python 3.10+, [uv](https://github.com/astral-sh/uv), Chrome, Chromium, Brave, Edge, or Vivaldi

```sh
git clone <repo>
cd browser-cli
uv sync
uv run browser-cli install brave   # or: chrome, chromium, edge, vivaldi
```

The `install` command will:
1. Ask you to load the `extension/` folder as an unpacked extension in your browser (`brave://extensions` → Developer mode → Load unpacked)
2. Ask you to paste the extension ID shown on the extension card
3. Write the native messaging manifest to your OS so the browser can find the host
4. Copy the native host into an internal `libexec` directory and create a small wrapper outside your `PATH`

After install, **fully restart your browser** (Quit and reopen — not just close the window). The extension will connect to the native host automatically on startup.

Only the `browser-cli` command needs to be on your `PATH`. The browser launches the native host wrapper directly from its absolute path in the native messaging manifest, and that wrapper points to the internally installed `native_host.py` copy.

---

## Project structure

```text
browser-cli/
├── browser_cli/
│   ├── __init__.py        # Python API — BrowserCLI class and Python API entry point
│   ├── cli.py             # Click CLI entry point
│   ├── client.py          # Unix socket client used by CLI and API
│   ├── models.py          # Tab and Group helper models
│   ├── native_host.py     # Native messaging host launched by the browser
│   └── commands/
│       ├── navigate.py    # nav open/reload/back/forward/focus
│       ├── search.py      # search engine shortcuts
│       ├── tabs.py        # tab management
│       ├── groups.py      # tab group management
│       ├── windows.py     # window management
│       ├── dom.py         # DOM querying and interaction
│       ├── extract.py     # content extraction
│       └── session.py     # session save/load
├── extension/
│   ├── manifest.json      # MV3 extension manifest
│   ├── background.js      # Service worker command dispatcher
│   └── content.js         # Content-script helpers
├── examples/
│   ├── demo.py            # Python API walkthrough
│   └── demo.sh            # Bash CLI walkthrough
├── tests/
│   ├── conftest.py        # shared pytest fixtures
│   ├── test_api.py
│   ├── test_cli.py
│   ├── test_dom.py
│   ├── test_extract.py
│   ├── test_groups.py
│   ├── test_nav.py
│   ├── test_session.py
│   ├── test_tabs.py
│   └── test_windows.py
├── com.browsercli.host.json  # native messaging manifest template
├── pyproject.toml            # package metadata and CLI entry point
└── uv.lock                   # locked dependencies for uv
```

---

## CLI reference

All commands are run with `uv run browser-cli [--browser ALIAS] <command>`.

If exactly one browser instance is connected, commands auto-target it. Use `--browser ALIAS` when multiple browser instances are connected. `tabs list`, `tabs count`, `groups list`, `groups count`, and `windows list` are the only commands that aggregate across all active browsers when `--browser` is omitted; in that mode they show the source browser alias or UUID. You can inspect the active instances with `browser-cli clients` and assign a persistent profile alias from inside the target browser with `browser-cli clients rename --browser <current-alias> <new-alias>`. Closed browsers are removed from the client registry automatically.

Important: profile aliases are browser-instance aliases, not window aliases. Window aliases created with `windows rename` are only for targeting windows in commands like `nav open --window work`. If a browser instance has no explicit profile alias set, the native host gives it a generated UUID alias so multiple unaliased browsers stay distinct.

### Navigation (`nav`)

```sh
# Open a URL
browser-cli nav open https://example.com
browser-cli nav open https://example.com --bg               # background, no focus
browser-cli nav open https://example.com --window work      # into a named window
browser-cli nav open https://example.com --group research   # into a tab group (name or ID)

# Reload
browser-cli nav reload                  # reload active tab
browser-cli nav reload 1234             # reload tab by ID
browser-cli nav hard-reload             # bypass cache

# Navigate history
browser-cli nav back
browser-cli nav forward 1234            # forward in specific tab

# Jump to a tab by URL pattern
browser-cli nav focus github            # focuses first tab whose URL contains "github"
```

### Search

Each search command opens the search results in your browser using the same flags as `nav open`.

```sh
browser-cli search google openai api
browser-cli search brave rust iterators --bg
browser-cli search ddg tab groups --window work
browser-cli search youtube browser automation
browser-cli search yt lo fi
browser-cli search spotify aphex twin
browser-cli search amazon mechanical keyboard
browser-cli search ecosia native messaging
browser-cli search furaffinity dragons
browser-cli search fa dragons
browser-cli search bing browser cli
browser-cli search github browser-cli
browser-cli search wikipedia native messaging
browser-cli search wiki native messaging
browser-cli search reddit chrome extensions
browser-cli search stackoverflow click choices
browser-cli search so click choices
```

### Tabs

```sh
browser-cli tabs list                        # list all open tabs (all windows)
browser-cli tabs count                       # count all tabs
browser-cli tabs count youtube               # count tabs matching URL pattern
browser-cli tabs filter youtube              # list tabs matching URL pattern
browser-cli tabs query "pull request"        # search tabs by URL or title

browser-cli tabs active 1234                 # switch browser focus to tab
browser-cli tabs html                        # print full HTML of active tab
browser-cli tabs html 1234                   # print HTML of specific tab

browser-cli tabs close 1234                  # close specific tab
browser-cli tabs close --inactive            # close all inactive tabs
browser-cli tabs close --duplicates          # close duplicate URLs (keep first)
browser-cli tabs dedupe                      # same as close --duplicates

browser-cli tabs move 1234 --window 2        # move tab to another window
browser-cli tabs move 1234 --group 42        # move tab into a group

browser-cli tabs sort --by domain            # sort tabs within each window
browser-cli tabs sort --by title
browser-cli tabs sort --by time

browser-cli tabs merge-windows               # pull all tabs into the current window
```

### Tab groups

```sh
browser-cli groups list                      # list all tab groups
browser-cli groups count                     # count groups
browser-cli groups query "work"              # search groups by name
browser-cli groups tabs 42                   # list tabs inside group ID 42

browser-cli groups create "research"         # create a new group
browser-cli groups add-tab research          # open a blank tab in the group
browser-cli groups add-tab research https://example.com  # open URL in the group
browser-cli groups add-tab 42 https://example.com        # by group ID

browser-cli groups close 42                  # ungroup the group
browser-cli groups move research --forward   # move group right
browser-cli groups move 42 --backward        # move group left
```

### Windows

```sh
browser-cli windows list                     # list all windows
browser-cli windows open                     # open a new window
browser-cli windows open https://example.com # open a new window on a URL
browser-cli windows rename 1 "work"          # give a window a local alias
browser-cli windows close 1                  # close a window
```

### DOM

These commands run on the **active tab**. The tab must be on a regular `http://` or `https://` page — not a browser internal page like `brave://newtab`.

```sh
browser-cli dom query "h1"                   # return elements matching CSS selector
browser-cli dom text "h1"                    # get text content of matching elements
browser-cli dom attr "a" href                # get attribute value from elements
browser-cli dom exists ".cookie-banner"      # exits 0 if found, 1 if not
browser-cli dom click ".accept-button"       # click an element
browser-cli dom type "#search" "hello"       # type text into an input
```

### Extract

```sh
browser-cli extract links                    # all <a href> links on the page
browser-cli extract images                   # all <img> tags (src + alt)
browser-cli extract text                     # all visible text (innerText)
browser-cli extract json "#data"             # parse JSON inside a CSS selector
browser-cli extract html                     # full HTML of the active tab
browser-cli extract markdown                 # main page content as Markdown
browser-cli extract markdown --selector "article"   # specific DOM subtree as Markdown
```

### Sessions

A session is a snapshot of all open tab URLs, stored inside the extension via `chrome.storage.local`. Sessions survive browser restarts but are lost if the extension is uninstalled or extension data is cleared.

```sh
browser-cli session save before-meeting      # save current tabs as a named session
browser-cli session load before-meeting      # reopen all saved tabs
browser-cli session list                     # list all saved sessions (name, tab count, date)
browser-cli session remove before-meeting    # delete a saved session
browser-cli session diff session-a session-b # show which URLs were added / removed
browser-cli session auto-save on             # auto-save after every tab change
browser-cli session auto-save off
```

### Misc

```sh
browser-cli clients                          # show connected browser info from the registry
browser-cli clients rename --browser abcd1234 work  # rename one connected browser instance
browser-cli --browser abcd1234 clients rename work  # equivalent global form
browser-cli install brave                    # (re)register the native host
browser-cli completion zsh                   # print setup instructions
browser-cli completion zsh --script          # output raw completion script
```

---

## Python API

```python
from browser_cli import BrowserCLI

b = BrowserCLI()
```

Every CLI command has a corresponding method. The call blocks until the browser responds and returns the data directly as a Python object.

```python
# Navigation
b.open("https://example.com")
b.open("https://example.com", background=True)
b.open("https://example.com", window="work")
b.reload()
b.hard_reload()
b.back()
b.forward(tab_id=1234)
b.focus_url("github")

# Tabs
tabs = b.tabs_list()          # list[Tab]; in multi-browser mode each tab.browser is set
b.tabs_active(1234)
b.tabs_close(1234)
b.tabs_close_inactive()
b.tabs_close_duplicates()
b.tabs_filter("youtube")      # list of matching tabs
b.tabs_query("pull request")
counts = b.tabs_count("github")  # int, or BrowserCounts(total=..., by_browser=...) in multi-browser mode
html = b.tabs_html()          # full HTML string of active tab
b.tabs_sort(by="domain")
b.tabs_merge_windows()
b.tabs_dedupe()

# Tab groups
groups = b.group_list()       # list[Group]; in multi-browser mode each group.browser is set
b.group_open("research")      # creates group, returns { id, name }
b.group_close(42)
b.group_tabs(42)              # tabs inside a group
b.group_count()               # int, or BrowserCounts(...) in multi-browser mode

# Windows
windows = b.windows_list()    # in multi-browser mode each dict has a "browser" key
b.windows_rename(1, "work")
b.windows_open()
b.windows_open("https://example.com")
b.windows_close(1)

# DOM  (active tab must be http/https)
elements = b.dom_query("h2")           # list of { tag, text, attrs }
texts = b.dom_text(".article p")       # list of strings
attrs = b.dom_attr("a", "href")        # list of strings
exists = b.dom_exists(".cookie-banner")# bool
b.dom_click(".accept-button")
b.dom_type("#search", "hello world")

# Extract
links = b.extract_links()     # list of { text, href }
images = b.extract_images()   # list of { alt, src }
text = b.extract_text()       # string
data = b.extract_json("#app-data")  # parsed Python object

# Sessions
b.session_save("before-meeting")
b.session_load("before-meeting")
sessions = b.session_list()   # [{ name, tabs, savedAt }, ...]
b.session_remove("before-meeting")
diff = b.session_diff("session-a", "session-b")
# diff = { "added": [...urls], "removed": [...urls] }
b.session_auto_save(True)

# Misc
clients = b.clients()
```

**Error handling**

```python
from browser_cli import BrowserCLI, BrowserNotConnected

b = BrowserCLI()
try:
    tabs = b.tabs_list()
except BrowserNotConnected:
    print("Browser is not running or extension is not loaded")
except RuntimeError as e:
    print(f"Browser returned an error: {e}")
```

```python
from browser_cli import BrowserCLI, BrowserCounts

b = BrowserCLI()

tabs = b.tabs_list()
for tab in tabs:
    print(tab.browser, tab.title)

counts = b.tabs_count()
if isinstance(counts, BrowserCounts):
    print(counts.total)
    print(counts.by_browser)
```

---

## Example scripts

See `examples/demo.py` (Python) and `examples/demo.sh` (Bash) for full walkthroughs covering tabs, groups, DOM extraction, and session management.

```sh
uv run python examples/demo.py
bash examples/demo.sh
```

---

## Limitations

- **Chrome internal pages** (`chrome://`, `brave://`, `about:`) cannot be scripted. DOM and extract commands only work on regular `http://` and `https://` pages.
- **Multiple browser instances can be auto-distinguished, but generated aliases are temporary**. Unaliased browsers get UUID aliases from the native host, which avoids collisions but is less ergonomic than setting a stable alias with `browser-cli clients rename --browser <current-alias> <new-alias>`.
- **Supported install targets are explicit, not “all Chromium browsers”**. The installer currently supports Chrome, Chromium, Brave, Edge, and Vivaldi. Other Chromium-based browsers may use different or shared native messaging manifest locations, so they need browser-specific verification before being added safely.
- **Linux and macOS only** — Windows native messaging paths are not yet handled.