Authenticated Browsing for AI Agents

Give your agent access to sites that require login, like X (Twitter), GitHub, LinkedIn, or any authenticated web app. Plasmate stores encrypted cookie profiles locally and injects them into requests so your agent can browse as you.

How It Works

  1. You log into a site normally in Chrome
  2. The Plasmate browser extension captures the auth cookies
  3. Plasmate encrypts and stores them locally on your machine
  4. Your agent uses the stored profile to make authenticated requests

No passwords leave your machine. No tokens are sent to any server. Everything stays local.

Prerequisites

Step 1: Install the Browser Extension

  1. Download or clone the extension repo:
    git clone https://github.com/plasmate-labs/plasmate-extension.git
  2. Open chrome://extensions in Chrome
  3. Enable Developer mode (top right toggle)
  4. Click Load unpacked and select the cloned folder
  5. Pin the Plasmate extension icon to your toolbar

Step 2: Start the Local Bridge

The bridge is a local HTTP server that the extension talks to. It only binds to 127.0.0.1 and never exposes anything to the network.

plasmate auth serve

You should see:

Auth bridge server listening on http://127.0.0.1:9271

Leave this running in a terminal tab.

Step 3: Log Into the Target Site

Open Chrome and log into the site you want your agent to access. For this guide we will use X (Twitter) as the example:

  1. Go to x.com and sign in normally
  2. Browse around briefly to make sure the session is active

Step 4: Push Cookies to Plasmate

  1. Click the Plasmate extension icon in your toolbar
  2. It auto-detects the current site and selects the relevant auth cookies
  3. Click Push to Plasmate
  4. A green confirmation appears. Done.

Step 5: Verify

plasmate auth info x.com

You should see something like:

Profile: x.com
Cookies: 4
Created: 2026-03-26T12:00:00Z
Status:  encrypted

The cookie values are never printed. Only metadata is shown.

Using the Profile

Direct CLI

Fetch any authenticated page:

plasmate fetch https://x.com/home --profile x.com

The output is a SOM JSON document with the full authenticated page content, ready for your agent to consume.

Via the Plasmate Server

Start the server with a profile loaded:

plasmate serve --protocol cdp --profile x.com

Now any agent that connects via CDP or AWP inherits the authenticated session.

Agent-Specific Setup

Claude Code (via MCP)

Add Plasmate as an MCP server in your Claude Code config (~/.claude/mcp.json or project .mcp.json):

{
  "mcpServers": {
    "plasmate": {
      "command": "plasmate-mcp",
      "args": ["--profile", "x.com"]
    }
  }
}

Now Claude Code can call the plasmate_fetch tool and it will automatically use your X session:

Use plasmate_fetch to get https://x.com/home and summarize my timeline

OpenClaw

If you are running OpenClaw, add Plasmate as a tool in your agent config:

tools:
  plasmate:
    command: plasmate-mcp
    args: ["--profile", "x.com"]

Your agent can then call plasmate_fetch from any conversation to browse X as you.

Cursor / Windsurf

Add to your MCP config (same format as Claude Code):

{
  "mcpServers": {
    "plasmate": {
      "command": "plasmate-mcp",
      "args": ["--profile", "x.com"]
    }
  }
}

Custom Agents (Python)

Use the Python SDK:

from plasmate import Plasmate

browser = Plasmate(profile="x.com")
result = browser.fetch("https://x.com/home")
print(result["title"])
for region in result["regions"]:
    for el in region["elements"]:
        print(el.get("text", ""))

Custom Agents (Node.js)

import { Plasmate } from 'plasmate';

const browser = new Plasmate({ profile: 'x.com' });
const result = await browser.fetch('https://x.com/home');
console.log(result.title);

Supported Sites

The extension auto-selects the right cookies for popular platforms:

Site Domain Key Cookies
X / Twitter x.com auth_token, ct0
GitHub github.com user_session, __Host-user_session_same_site
LinkedIn linkedin.com li_at, JSESSIONID
Reddit reddit.com reddit_session, token_v2
YouTube youtube.com SID, HSID, SSID

For any other site, navigate there in Chrome, click the extension, and push. If you are unsure which cookies matter, push all of them.

Managing Profiles

# List all stored profiles
plasmate auth list

# View profile metadata (never prints cookie values)
plasmate auth info github.com

# Delete a profile
plasmate auth revoke x.com

Security Notes

Next Steps