What it is
OpenTabs connects an MCP client to your real Chrome browser. A Chrome extension bridges your open tabs to a server on your machine, and plugins turn each web app's own internal APIs into MCP tools, so the agent acts as you on sites where you are already signed in. The README lists more than 100 plugins with about 2,000 tools, including Slack, Discord, GitHub, Jira, Notion, Figma, AWS and Stripe, plus general browser tools for screenshots, clicking, typing and network capture.
The server speaks Streamable HTTP on 127.0.0.1:9515, protected by a 64-character bearer secret in ~/.opentabs/extension/auth.json, and rejects requests carrying a browser Origin header to block DNS rebinding. A gateway endpoint exposes just two tools, opentabs_list_tools and opentabs_call, to save context; a stdio bridge relays to the HTTP server, and a CLI mode skips MCP entirely. It needs Node.js 22 or later and Chrome, with the extension loaded unpacked in developer mode.
It is MIT licensed with about 990 GitHub stars. The latest release is still 0.0.115 from 27 July 2026, and it is not listed in the official MCP registry. Anonymous telemetry, sent to PostHog's US region, is on by default; opentabs telemetry disable or DO_NOT_TRACK=1 turns it off.
Install
npm install -g @opentabs-dev/cli && opentabs startOur review
OpenTabs solves a real problem in an alarming way: it gives an agent your logged-in identity on every site you use, with no API keys or OAuth apps in between. Calling a site's own API is faster and less brittle than screenshot-driven automation, and the gateway keeps 2,000 tools from flooding the context window, but the convenience and the risk are the same feature.
Whatever you are logged into, the agent can use as you: send Slack messages, merge pull requests, change AWS settings. A prompt injection in a page or email the agent reads could ride that access. The defaults help: every tool starts off, each plugin or tool is set to Off, Ask or Auto, permissions reset when a plugin updates, and the last 500 actions are queryable from the audit log. The docs also note that if no secret is configured the server checks nothing, and OPENTABS_DANGEROUSLY_SKIP_PERMISSIONS turns every check off.
Plugins depend on undocumented internal APIs that sites change without notice. Issue #154, an Instacart get_order call failing on a GraphQL variable format, is the typical failure. Using those APIs may also breach a service's terms, and the project's disclaimer puts that on you. Plugins are npm packages, community ones included, so installing one means running someone's code inside your signed-in browser.
Maturity is the other caution. Versions are still 0.0.x, there has been no release since July, and the tool-call timeout of 30 seconds (5 minutes with progress reports) and 10 MB message cap show its desktop origins. For GitHub, Slack or Stripe, the vendors' own servers act through scoped tokens an admin can revoke; OpenTabs' scope is whatever your browser cookies allow, and that difference outweighs any number of plugins.
Where it earns its place
A freelance consultant working as a guest in several clients' Slack and Notion workspaces
Pull a weekly digest of mentions and page changes across all of them
Guests often cannot install apps or create integrations, but OpenTabs uses the session already open in Chrome, so read tools can run on Auto. It is free; the same bypass may break a client's policies, which is the consultant's risk to weigh.
A support engineer at a SaaS company with a dozen internal admin consoles
Let an agent look up a customer across web tools that have no public API
Scaffold a plugin with the SDK, or let the agent discover the site's API and draft one, then call it through the gateway. It saves tab-switching, but every change to an internal API breaks the plugin until someone fixes it.
A security lead reviewing developer tools at a 200-person company
Decide whether staff may install OpenTabs on work machines
The extension runs unpacked in developer mode and can act with every SSO session in the browser, including production consoles such as AWS. Workable controls are a separate Chrome profile with only low-risk logins, Ask on all write tools and audit-log review.
Before you commit
- Setup
- npm install -g @opentabs-dev/cli && opentabs start, load ~/.opentabs/extension unpacked in chrome://extensions, then opentabs plugin install <name>. Configs are documented for Claude Code, OpenCode, Cursor and Windsurf; each tool must also be enabled before first use.
- Integrations
- 100+ plugins and about 2,000 tools per the README, plus built-in browser tools for screenshots, clicks, typing and network capture. Most plugins mix read and write tools; the gateway exposes only opentabs_list_tools and opentabs_call.
- Data and privacy
- Tools act with your browser cookies on every signed-in site, and pages or messages the agent reads are untrusted input. Everything runs locally, with an audit log at ~/.opentabs/audit.log; telemetry goes to PostHog until disabled. The repo lists no security advisories.
- Cost at scale
- Free; the binding limits are each site's own. Heavy agent use goes through your personal account and can trip that site's rate limits or abuse detection; OpenTabs itself allows 25 concurrent calls per plugin and 5 new MCP sessions a minute.
- Limits
- Tool calls time out at 30 seconds, extendable to 5 minutes; messages are capped at 10 MB; only one extension can connect at a time. Plugins break when sites change their internal APIs.
What's good
- No API keys or OAuth apps; uses existing sessions
- Calls real APIs rather than clicking through pages
- Tools off by default with Off/Ask/Auto per tool
- Gateway mode cuts the tool list to two
What's not
- Agent can act as you on every logged-in account
- Plugins break when sites change internal APIs
- May conflict with services' terms of use
- 0.0.x; no release since July 2026
Best for
Power users who want an agent to work across web apps without official APIs and will set per-tool permissions carefully.
Alternatives
OpenTabs: common questions
- Is OpenTabs worth it?
- A clever route around API keys and OAuth that hands your agent every account you are logged into, so its permission settings matter more than its plugin count. We rate it 3.6 out of 5.
- How much does OpenTabs cost?
- Free and open source (MIT). No paid tier.
- What are the downsides of OpenTabs?
- Agent can act as you on every logged-in account; plugins break when sites change internal APIs; may conflict with services' terms of use; 0.0.x; no release since July 2026.
- Who is OpenTabs best for?
- Power users who want an agent to work across web apps without official APIs and will set per-tool permissions carefully.
- How much does OpenTabs cost for a team or in production?
- Free; the binding limits are each site's own. Heavy agent use goes through your personal account and can trip that site's rate limits or abuse detection; OpenTabs itself allows 25 concurrent calls per plugin and 5 new MCP sessions a minute.
- Is OpenTabs safe for company data?
- Tools act with your browser cookies on every signed-in site, and pages or messages the agent reads are untrusted input. Everything runs locally, with an audit log at ~/.opentabs/audit.log; telemetry goes to PostHog until disabled. The repo lists no security advisories.
- What are the best OpenTabs alternatives?
- The closest alternatives we have reviewed are Playwright MCP, Chrome DevTools MCP and Browserbase MCP.
Answers checked Oct 23, 2026.