octop-browser 1.0.0

Agent-first lightweight browser automation — direct CDP, no Playwright, more accurate and more reliable.

Overview · Highlights · Core Technology · Features · Quick Start · Contents

English · 中文

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📌 Overview

Octop Browser is a lightweight browser-use style tool that makes an agent's browser usage more accurate and reliable. Unlike typical stacks that route every action through Playwright, it launches a real Chromium and talks to the Chrome DevTools Protocol (CDP) directly — removing the intermediate layer so element targeting is driven by stable, live DOM refs and rarely misses.

Under the hood it starts a Chromium process with a --remote-debugging-port and speaks CDP itself. Because element references come straight from the live page, the agent acts on the real nodes, and those refs stay valid through reflows and re-renders — the result is higher action accuracy and lower token usage, with a persistent profile so logins don't expire mid-task.

Octop Browser's design goal: give an agent a browser it can act on with confidence — accurate clicks, low token cost, and persistent logins — through a small, well-shaped set of tools and a matching CLI.

Note: the install-browser command may bootstrap Playwright once purely to download a Chromium binary. Playwright is not a runtime dependency — the agent always drives the browser over CDP.

✨ Highlights

	Feature	Description
⚡	Direct CDP	Connects straight to Chrome via CDP — no Playwright / intermediate layer
🎯	Ref-based targeting	Stable element refs survive layout reflows, so clicks land where intended
🪶	Lightweight DOM	Token-efficient multi-level DOM keeps prompts small
🔐	Auth persistence	Profile-based logins persist across sessions — no repeated sign-in
🛠️	Agent tools	One stateless browser_tool with ~20 actions
💻	CLI	Every action available as a first-class command
🎬	Record & replay	Capture a workflow, then replay it as skill-guided agentic execution
🤖	MCP server	Expose the browser to any MCP-capable agent

🧠 Core Technology

Layer	Technology
Language	Python 3.11+
Transport	CDP over websockets (hand-rolled async client)
Launcher	subprocess Chromium with --remote-debugging-port
DOM	Multi-level builder + stable ref system
Tools	Stateless browser_tool action set
Recording	Injected JS recorder + semantic collapse + skill generator
Interfaces	CLI + MCP server
Build / quality	hatchling · ruff · mypy · pytest

🤔 Features

Browser tools

browser_tool(action=...) exposes the following actions:

Action	Description	Action	Description
navigate	Navigate the active tab	select	Pick a <select> option
dom_tree	Dump the multi-level DOM	scroll	Scroll the viewport
screenshot	Capture a screenshot	hover	Hover an element
click	Click by ref	eval_js	Run JavaScript
type	Type text by ref	go_back / go_forward	History nav
fill	Fill a field by ref	reload	Reload the page
press	Press a key	new_tab / close_tab	Tab control
wait	Wait for a condition	switch_tab / list_tabs	Tab management
		close_session	Close the CDP connection (pass kill=True to also stop Chrome)

CDP session

• BrowserSession.create(profile=...) opens a persistent Chromium session.
• Stateless helper: browser_tool(action="navigate", url=..., profile="work").
• Set BROWSER_USE_IDLE_TIMEOUT_MINUTES to stop a local Chrome profile after that many minutes without real CDP activity (0, the default, disables it).
• await session.close(kill=True) or browser_tool(action="close_session", profile="work", kill=True) stops the local Chrome process immediately. Profile data and login state stay on disk.

CLI

Every tool is also a CLI command:

octop-browser install-browser     # fetch a Chromium binary (one-time)
octop-browser navigate "https://example.com" --profile work
octop-browser dom-tree --profile work
octop-browser click --ref inp_1 --profile work
octop-browser type "octop" --ref inp_1 --profile work
octop-browser screenshot --profile work
octop-browser close-session --kill --profile work   # also stop Chrome
# session: open / close-session / new-tab / switch-tab / close-tab / list-tabs

Record & replay

Octop Browser can record a real browsing session and replay it:

1. octop-browser record daemon-start — launch the long-lived recording daemon.
2. octop-browser record start — begin capturing the active tab.
3. Browse normally. A small injected script captures clicks, typed text, navigations, and submits, with privacy redaction of sensitive fields.
4. octop-browser record stop — stop capturing.
5. octop-browser record generate-steps <id> — inspect the semantic steps; record generate-skill <id> emits a draft Skill (draft.skill.md).
6. octop-browser replay run <id> — re-execute as skill-guided agentic execution (the model replays intent, not brittle coordinates/refs).

Use record list / record show <id> / record status / record doctor to manage recordings.

MCP server

octop-browser ships an MCP server, so any MCP-capable agent can drive the browser through the same tool set.

python -m octop_browser.mcp_server   # or: make mcp

It speaks MCP over stdio, which is the transport most agent clients expect.

Over MCP each action is exposed as its own tool named after it — browser_navigate, browser_click, browser_dom_tree, browser_close_session, browser_record_start, install_browser, … — rather than as a single dispatching tool. Arguments match the Python API, so browser_close_session also takes kill to terminate Chrome.

Agent skills

The skills/ directory ships ready-made Skill files for agents that support skill loading — skills/octop-browser/SKILL.md (English) and skills/octop-browser-zh/SKILL.md (Chinese). They encode the safe usage pattern: run dom-tree before every click, pass refs instead of coordinates, and reuse named profiles for login state. record generate-skill emits a draft Skill in the same format.

🚀 Quick Start

Prerequisites

• Python 3.11+ — verified on 3.11 and 3.12. Higher-level applications built on top of it (e.g. Octop) may require a newer Python; follow their own docs.
• A Chromium / Chrome binary (auto-downloaded by install-browser)

1. Install

pip install octop-browser
octop-browser install-browser    # fetch a Chromium binary once

2. Use as a library

from octop_browser import BrowserSession

async with await BrowserSession.create(profile="default") as session:
    await session.navigate("https://example.com")
    dom = await session.dom_tree()
    await session.click(ref="btn_1")

Or statelessly:

from octop_browser import browser_tool

await browser_tool(action="navigate", url="https://example.com", profile="work")

3. Use as a CLI

octop-browser navigate "https://example.com" --profile work
octop-browser dom-tree --profile work

4. Record a workflow

octop-browser record daemon-start
octop-browser record start
# ... interact with the page ...
octop-browser record stop
octop-browser record generate-skill <recording_id>   # emit a draft Skill
octop-browser replay run <recording_id>              # replay it

📑 Contents

• Overview
• Highlights
• Core Technology
• Features
• Quick Start
• Reference
  • CLI reference
  • Python API
  • Configuration
  • Development
• Project Info
  • Contributing
  • Related projects
  • License

📖 CLI reference

Command	Description
install-browser	Download a Chromium binary (one-time bootstrap)
navigate	Navigate the active tab to a URL
open	Start a session and open one or more URLs as separate tabs
dom-tree	Print the multi-level DOM
screenshot	Capture a screenshot
click / type / fill / press	Interact by ref
wait / select / scroll / hover	Page control
eval-js	Run JavaScript
go-back / go-forward / reload	History / reload
new-tab / switch-tab / close-tab / list-tabs	Tab management
close-session	Detach from a profile's CDP session. Chrome keeps running so a later command re-attaches; add --kill to terminate it and free its port
record ...	doctor, daemon-start, daemon-stop, status, start, stop, list, show, generate-steps, generate-skill
replay run <id>	Replay a recorded workflow

Record & replay options

Option	Values	Purpose
record start --privacy	none · mask-sensitive (default) · mask-all	Redact typed values before they are written to disk. mask-sensitive masks fields that look sensitive (password, token, secret, otp, jwt, … matched against the field's type / name / id / placeholder / label); mask-all masks every typed value
replay run --input key=value	repeatable	Supply a value for a {{placeholder}} step at replay time

Redacted values are stored as the placeholder {{sensitive_value}}, so a recording that captured a login can still be replayed safely — keep the secret in the environment and pass it in at replay time:

octop-browser replay run <recording_id> --input sensitive_value="$MY_PASSWORD"

DOM levels

dom-tree (and the dom_tree action) takes --level to trade detail for tokens:

Level	Cost	Contents
minimal	~50 tokens	Title / URL only
interactive (default)	~200–500	Clickable / typeable elements with refs
full	~1k–3k	Full readable page
structured	varies	JSON, for programmatic use

octop-browser dom-tree --level minimal      # cheap page check
octop-browser dom-tree --level structured   # JSON for scripts

🐍 Python API

Exports

Everything below is importable from the package root: from octop_browser import ...

Symbol	Kind	Purpose
BrowserSession	class	Persistent CDP session — await BrowserSession.create(profile="work")
browser_tool	async fn	Stateless one-shot action — await browser_tool(action="click", ref="btn_1")
ToolResult	model	Return value of every session method and browser_tool()
ActionMetrics	model	Per-action timing / token counters
TabInfo	model	One tab: tab_id · url · title · active
OctopSettings	model	Full settings object — pass via BrowserSession.create(settings=...)
settings	instance	Process-wide default, built from the environment at import time
BrowserMode	type	Literal["auto", "headed", "headless"]
chromium_executable	fn	Path of the managed Chromium binary, or None if absent
ensure_chromium	fn	Blocking install — returns True once a binary is ready
install_chromium_stream	async gen	Same install as an event stream, for progress UIs
InstallEvent	TypedDict	One install event: a log line, or terminal done / success / error

Tool results

Every session method and browser_tool() call returns a ToolResult:

Field	Type	Notes
success	bool	False means the action failed — inspect error
content	str | dict	Main payload: DOM text, screenshot path, JS return value, …
error	str | None	Failure reason; None on success
metrics	ActionMetrics	action · duration_ms · dom_nodes_scanned · estimated_tokens · screenshot_size_kb
metadata	dict | None	Optional side-channel — e.g. screenshot reports page url / title here

res = await session.dom_tree(level="interactive")
if res.success:
    print(res.content, res.metrics.estimated_tokens)

session.metrics_summary() aggregates running totals for the whole session.

Hooks

BrowserSession mixes in HooksMixin, so callbacks can observe every action:

@session.on("after_action")
async def log_metrics(metrics):  # metrics: ActionMetrics
    print(metrics.action, metrics.duration_ms)

Event	Payload	Fired
before_action	dict — {"action": str, "params": dict}	Before each action is dispatched
after_action	ActionMetrics	After an action succeeds
action_error	ToolResult	After an action returns success=False
page_navigated	—	Reserved: accepted by on(), not emitted yet

Callbacks may be sync or async, and an exception inside a hook is logged without breaking the action.

⚙️ Configuration

Every setting is read from the environment at import time. You can also build a OctopSettings object explicitly and hand it to BrowserSession.create():

from octop_browser import BrowserSession, OctopSettings

settings = OctopSettings(cdp_port_start=9300, cdp_timeout=60.0)
session = await BrowserSession.create(profile="work", settings=settings)

Variable	Default	Purpose
BROWSER_USE_MODE	auto	Launch mode: auto / headed / headless (auto picks headed on macOS/Windows or when DISPLAY is set)
BROWSER_USE_CDP_WS_URL	(unset)	Connect straight to an existing Chrome DevTools WebSocket URL — use this for remote / Docker Chrome and skip the launcher
BROWSER_USE_CHROME_BIN	auto-detect	Absolute path to the Chrome / Chromium binary
BROWSER_USE_PROFILES_DIR	~/.octop-browser/profiles	Base directory for Chrome user-data-dirs
BROWSER_USE_SCREENSHOTS_DIR	~/.octop-browser/screenshots	Where the screenshot action writes PNGs
BROWSER_USE_CDP_HOST	localhost	Host serving Chrome's CDP endpoint
BROWSER_USE_CDP_PORT_START	9222	First CDP debug port assigned to profiles
BROWSER_USE_CDP_TIMEOUT	30.0	Seconds to wait for a CDP command response
BROWSER_USE_VIEWPORT_WIDTH	1440	Viewport width in CSS pixels
BROWSER_USE_VIEWPORT_HEIGHT	900	Viewport height in CSS pixels
BROWSER_USE_IDLE_TIMEOUT_MINUTES	0 (off)	Stop a locally managed Chrome after N minutes without real CDP activity
BROWSER_USE_LAUNCH_RETRIES	20	How many times to poll Chrome after launch
BROWSER_USE_LAUNCH_DELAY	0.25	Seconds between launch polls
BROWSER_USE_CDP_MAX_MESSAGE_SIZE	33554432 (32 MiB)	Max CDP WebSocket frame size; 0 disables the cap (raise it for very large screenshots)
BROWSER_USE_NO_SANDBOX	auto-detect	Force (1) or forbid (0) --no-sandbox. When unset, it is added only if the kernel denies unprivileged user namespaces (typical in containers)
BROWSER_USE_DISABLE_GPU	auto (on in headless)	Force (1) / forbid (0) --disable-gpu. Defaults to on in headless mode, off in headed mode
BROWSER_USE_DISABLE_DEV_SHM_USAGE	auto (on in Linux)	Force (1) / forbid (0) --disable-dev-shm-usage. Defaults to on on Linux, where Docker's 64 MiB /dev/shm is too small for Chrome

🛠️ Development

Prerequisites: Python 3.11+, uv

make install          # uv sync --extra dev (falls back to pip install -e ".[dev]")
make all              # format + lint + typecheck + test

🤝 Contributing

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Run make all before submitting
4. Open a Pull Request against main

See CONTRIBUTING.md for branching, PR, and release details (release/* → main auto-publishes to PyPI).

Found a vulnerability? Please follow the private disclosure process in SECURITY.md instead of opening a public issue. Release notes for every version live in CHANGELOG.md.

🔗 Related projects

Project	Description
harness-agent	Agent runtime that drives the browser tools
harness-memory	Memory system for browser-backed agents
harness-gateway	Multi-platform IM channel bridge
Octop	The self-hosted assistant that composes the Harness stack

📄 License

This project is licensed under the MIT License.