mcp

---

One MCP server gives your coding agent everything pre.dev does:

• Browser Agents Local: your own Chrome. Open a tab in your work profile, read a dashboard you are already logged into, fill in a form, click through a flow and screenshot the result, all in the Chrome you use every day. No second browser, nothing to log into again, no cookies copied anywhere.
• Browser Agents in the cloud. Send a URL and a task to pre.dev's browsers and get structured data back, many runs in parallel.
• Specs and plans. Plan an app or feature before building it: architecture, tech stack, milestones and user stories.

It works with any coding agent: Claude Code, Codex, Hermes, Pi, OpenClaw, Cursor, GitHub Copilot, Cline, Gemini CLI and Antigravity, OpenCode, Zed, Goose, the pre.dev CLI and 20 more, and any agent that can run a shell command. Run as many agents as you like at the same time. They all share one connection to Chrome, so Chrome only asks you to allow it once.

Built with the pre.dev CLI.

Quick start

You need macOS, Google Chrome and Node.js 22 or newer (check with node --version). Run one command:

npx -y @predotdev/mcp setup

It walks you through everything:

1. Adds it to every coding agent on your Mac: Claude Code, Codex, Hermes, Pi, OpenClaw, Cursor, Copilot CLI, Cline, Antigravity, Gemini CLI, OpenCode, VS Code, Claude Desktop, the pre.dev CLI and more (28 in all; list). Already using the hosted pre.dev MCP? This one includes all of its tools, so setup replaces it.
2. Connects to Chrome. The first time, it asks you to turn on remote debugging at chrome://inspect/#remote-debugging (it copies the address for you), and Chrome asks "Allow remote debugging?": click Allow.
3. Signs you in to pre.dev in your browser (or creates a free account), for plain-words actions and the cloud tools. Approve, and your key is saved for every agent; nothing to copy. Already signed in to the pre.dev CLI? It uses that login. Optional: press Enter to skip, and the Chrome tools still work.

Then restart your agent and try:

List my Chrome profiles and the tabs I have open.

[!TIP] Or let your agent do it. Paste this into Claude Code (or any coding agent): Run npx -y @predotdev/mcp setup with a 10 minute timeout and tell me what to click.

The command is safe to run again at any time. The copy it installs keeps itself up to date (see How it works), and running setup again also updates it. npx -y @predotdev/mcp check shows the state of everything, and uninstall removes it from every agent.

Coming from Claude in Chrome?

Run the setup command above, then type /chrome in Claude Code and turn off Enabled by default (or start a session with claude --no-chrome). Your Chrome profiles and logins carry over, because this server drives the Chrome you already use. The switching guide maps each Claude in Chrome tool to its pre.dev tool and has a line you can paste into CLAUDE.md.

Local or cloud?

Both editions of pre.dev Browser Agents are in this server, and your agent picks per task.

	Local (chrome_* tools)	Cloud (browser_agent)
Runs in	Your own Chrome	pre.dev's browsers
Logged in as	You, in every profile you use	Nobody (public pages)
Driven by	Your coding agent, step by step	One API call with a URL and a task
Best for	Dashboards, internal tools, admin panels, anything behind your login	Structured data from public sites, many runs in parallel
Also available	Only here	The REST API and SDKs

What your agent can do

In your own Chrome (run on your Mac):

Tool	What it does
chrome_profiles	List your Chrome profiles (name, Google account) and how many tabs each has open
chrome_tabs	List open tabs grouped by profile
chrome_open	Open a URL in a specific profile, in the background by default so you are not interrupted; returns once the page has loaded
chrome_navigate	Load a URL in a tab, or go back, forward or reload
chrome_snapshot	List the clickable and typeable elements on a page as short refs ([e1], [e2], ...), with each link's address (tracking parameters removed)
chrome_click	Click by ref, CSS selector, visible text or coordinates, with real mouse events
chrome_type	Type into inputs, text areas, rich editors and dropdowns
chrome_act	Click or type into an element described in plain words, in one call (plain-words actions)
chrome_press	Press keys and shortcuts (Enter, Tab, cmd+a, shift+Tab)
chrome_scroll	Scroll the page or bring an element into view
chrome_read	Read a page's text without site menus, footers and off-screen panels (full keeps them), paged for long pages. selector reads just the matching elements and links adds their URLs, so a results page's names, prices and product links come back in one call. When a selector matches nothing, it lists the page's repeated items (result cards) with selectors that work
chrome_screenshot	Screenshot the visible area or the full page
chrome_wait	Wait for text, a selector, a URL change, or a plain-words condition; with only a tab, until the page has loaded and stopped changing
chrome_eval	Run JavaScript in the page and return the result
chrome_upload	Attach local files to an upload button or file input
chrome_show	Bring a tab to the front so you can see it or take over
chrome_close	Close a tab

In pre.dev's cloud (need a pre.dev plan; on the free plan your agent sees them and can open the subscribe page for you):

Tool	What it does
browser_agent	Run one or more tasks in pre.dev's cloud browsers: a URL plus an instruction or a JSON Schema for the output; returns each task's data
browser_agent_list / browser_agent_get	Earlier cloud runs, and one run with its step-by-step events
fast_spec / deep_spec	Plan an app or feature: architecture, tech stack, milestones and user stories (deep_spec adds subtasks)
get_spec / list_specs	A spec's status and result, and the specs you have made
get_plan	The verified plan of a project you own

This is what your agent sees when it takes a snapshot:

Tab A137CF · Work <you@company.com> · Create your account
https://example.com/signup
Headings: "Create your account"
Scroll: 0/640px
[e1] textbox "Full name"
[e2] textbox "Email" value="you@company.com"
[e3] select "Plan" selected="Free"
[e4] checkbox "I agree to the terms" [unchecked]
[e5] button "Create account"

Every tab is labeled with the profile it belongs to, so the agent always knows which account it is acting as.

Plain-words actions

Once you are signed in to pre.dev (setup or login does it, or set PREDEV_API_KEY), two things turn on:

• chrome_act: click or type into an element described in plain words, like "the Create button in the dialog", in under a second with no snapshot needed. If it isn't sure, it lists the likely matches instead of guessing.
• chrome_wait with condition: wait until a plain-words statement about the page is true, like "the export has finished".

Pricing. The MCP server is free and open source, and the Chrome tools run free on your Mac. Plain-words actions and the cloud tools use pre.dev credits, the same credits as the rest of pre.dev (pricing). Each action costs a small fraction of one credit, and the free trial's credits cover hundreds of them. They show up in your usage as browser-agents-local, and check shows your plan. If the free plan's allowance or your credits run out, your agent tells you and offers to open the billing page in your Chrome; everything else keeps working. Every other tool runs entirely on your machine and never calls pre.dev.

Setup for every agent

setup does this for you. To add it by hand instead (for example to an agent setup doesn't know), every agent runs the same command. Sign in once with npx -y @predotdev/mcp login and leave the key out, or put your key from Integrations → Built-in in the agent's environment:

npx -y @predotdev/mcp        env: PREDEV_API_KEY=your_key   (optional after login)

setup finds and configures each of these that is installed: Claude Code, Codex, Hermes, Pi, OpenClaw, Cursor (editor and CLI), Windsurf, GitHub Copilot CLI, Antigravity, Gemini CLI, Cline, Kiro, Qwen Code, Factory Droid, Augment, Amp, Kilo Code, Kimi Code, Junie, Warp, Rovo Dev, OpenHands, LM Studio, OpenCode, VS Code, VS Code Insiders, Claude Desktop and the pre.dev CLI. Devin CLI, Grok Build and Warp also read Claude Code's or Cursor's config, so they pick it up from there. Zed's settings file usually has comments, so setup leaves it to you (below).

claude mcp add --scope user predev -e PREDEV_API_KEY=your_key -- npx -y @predotdev/mcp

hermes mcp add predev --command npx --args -y @predotdev/mcp
hermes config set mcp_servers.predev.timeout 900

Answer Y to turn on its tools. The longer timeout gives specs and cloud runs time to finish. In a running chat, /reload-mcp picks it up.

pi mcp add predev -- npx -y @predotdev/mcp
pi mcp list

pi mcp list should say predev: connected. pi mcp add needs Pi 0.99 or newer. On an older Pi, run pi install npm:pi-mcp-adapter and add the predev entry to ~/.pi/agent/mcp.json by hand (setup writes it for you).

In the pre.dev CLI, type /chrome (and /chrome off to turn it off). The CLI has pre.dev's cloud tools built in, so it only needs the Chrome tools, and the server uses your pre.dev CLI login. /chrome and setup both add this to ~/.predev/mcp.json:

{
  "mcpServers": {
    "predev": {
      "command": "npx",
      "args": ["-y", "@predotdev/mcp"],
      "env": { "PREDEV_MCP_CLOUD": "off" }
    }
  }
}

The agent sees the tools as predev_chrome_open, predev_chrome_act and so on.

From the pre.dev CLI, predev mcp setup runs this package's setup for your other agents.

codex mcp add predev --env PREDEV_API_KEY=your_key -- npx -y @predotdev/mcp

Or add this to ~/.codex/config.toml. The longer timeout gives specs and cloud runs time to finish:

[mcp_servers.predev]
command = "npx"
args = ["-y", "@predotdev/mcp"]
env = { PREDEV_API_KEY = "your_key" }
tool_timeout_sec = 900

Add to ~/.cursor/mcp.json, then restart Cursor:

{
  "mcpServers": {
    "predev": {
      "command": "npx",
      "args": ["-y", "@predotdev/mcp"],
      "env": { "PREDEV_API_KEY": "your_key" }
    }
  }
}

Add to ~/.codeium/windsurf/mcp_config.json, then restart Windsurf:

{
  "mcpServers": {
    "predev": {
      "command": "npx",
      "args": ["-y", "@predotdev/mcp"],
      "env": { "PREDEV_API_KEY": "your_key" }
    }
  }
}

Add to .vscode/mcp.json in your project, or run MCP: Open User Configuration to add it for every project:

{
  "servers": {
    "predev": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@predotdev/mcp"],
      "env": { "PREDEV_API_KEY": "your_key" }
    }
  }
}

Add to ~/.gemini/settings.json:

{
  "mcpServers": {
    "predev": {
      "command": "npx",
      "args": ["-y", "@predotdev/mcp"],
      "env": { "PREDEV_API_KEY": "your_key" }
    }
  }
}

Add to ~/.config/opencode/opencode.json:

{
  "mcp": {
    "predev": {
      "type": "local",
      "command": ["npx", "-y", "@predotdev/mcp"],
      "environment": { "PREDEV_API_KEY": "your_key" },
      "enabled": true
    }
  }
}

Desktop apps don't load your shell's PATH, so give them full paths. Install once:

npm install -g @predotdev/mcp

Then print the exact entry to paste:

echo "\"predev\": {\"command\": \"$(which node)\", \"args\": [\"$(npm root -g)/@predotdev/mcp/src/bridge.mjs\"], \"env\": {\"PREDEV_API_KEY\": \"your_key\"}}"

Put that entry inside "mcpServers" in ~/Library/Application Support/Claude/claude_desktop_config.json, replace your_key, then restart Claude Desktop. The same trick works for any app that says it can't find npx or node.

Every entry below is the same server: command npx, arguments -y @predotdev/mcp.

Agent	Command, or file and key
GitHub Copilot CLI	copilot mcp add predev -- npx -y @predotdev/mcp, or ~/.copilot/mcp-config.json under mcpServers (add "type": "local", "tools": ["*"])
Antigravity (agy)	~/.gemini/config/mcp_config.json under mcpServers
Cline	cline mcp add predev --yes -- npx -y @predotdev/mcp, or ~/.cline/data/settings/cline_mcp_settings.json under mcpServers
Kiro	kiro-cli mcp add --name predev --command "npx -y @predotdev/mcp" --scope global, or ~/.kiro/settings/mcp.json
Qwen Code	qwen mcp add --scope user predev npx -y @predotdev/mcp
Factory Droid	droid mcp add predev "npx -y @predotdev/mcp"
Augment (Auggie)	auggie mcp add predev --command npx --args "-y @predotdev/mcp"
Amp	amp mcp add predev -- npx -y @predotdev/mcp
OpenClaw	openclaw mcp set predev '{"command":"npx","args":["-y","@predotdev/mcp"]}'
Grok Build	grok mcp add predev -- npx -y @predotdev/mcp
Devin CLI	devin mcp add -s user predev -- npx -y @predotdev/mcp
OpenHands	openhands mcp add predev --transport stdio npx -- -y @predotdev/mcp
Kilo Code	~/.config/kilo/kilo.jsonc under mcp: "predev": {"type": "local", "command": ["npx", "-y", "@predotdev/mcp"], "enabled": true}
Kimi Code	~/.kimi-code/mcp.json under mcpServers
Junie	~/.junie/mcp/mcp.json under mcpServers
Warp	~/.warp/.mcp.json under mcpServers
Rovo Dev	~/.rovodev/mcp.json under mcpServers (add "transport": "stdio")
LM Studio	~/.lmstudio/mcp.json under mcpServers
JetBrains AI Assistant	Settings → MCP → Import from Claude (after setup adds it to Claude Desktop)

In ~/.config/zed/settings.json:

"context_servers": {
  "predev": { "command": "npx", "args": ["-y", "@predotdev/mcp"], "env": {} }
}

In ~/.config/goose/config.yaml, under extensions::

  predev:
    type: stdio
    name: predev
    enabled: true
    cmd: npx
    args: [-y, "@predotdev/mcp"]
    envs: {}
    timeout: 900

For one session only: goose session --with-extension "npx -y @predotdev/mcp".

Continue, in ~/.continue/config.yaml:

mcpServers:
  - name: predev
    command: npx
    args: ["-y", "@predotdev/mcp"]

Crush, one line in ~/.config/crush/crushrc:

mcp add predev --command npx --args -y --args @predotdev/mcp

Mistral Vibe, in ~/.vibe/config.toml:

[[mcp_servers]]
name = "predev"
transport = "stdio"
command = "npx"
args = ["-y", "@predotdev/mcp"]

Every tool also runs from a shell, so any agent that can run commands can drive your Chrome:

npx -y @predotdev/mcp tools                       # list the tools and their arguments
npx -y @predotdev/mcp call chrome_open '{"profile":"Personal","url":"https://example.com"}'
npx -y @predotdev/mcp call chrome_snapshot '{"tab":"A1B2C3"}'
npx -y @predotdev/mcp call chrome_click '{"tab":"A1B2C3","ref":"e4"}'

Text goes to stdout, a screenshot is saved to a file and its path is printed, and the exit code is 1 when the tool failed. Point your agent at this section, or paste npx -y @predotdev/mcp tools into its instructions.

Add a local (stdio) server with command npx, arguments -y @predotdev/mcp, and the environment variable PREDEV_API_KEY. If the client can't find npx, use the full-path setup from the Claude Desktop section.

How it works

flowchart LR
  A["Claude Code"] --> D
  B["Codex"] --> D
  C["Cursor"] --> D
  D["pre.dev MCP background process<br/>(one per Chrome)"] -- "one approved connection" --> E["Your Chrome<br/>(every profile)"]
  D -. "plain-words actions and cloud tools" .-> F["pre.dev API"]

• Chrome asks you to approve each debugging connection. Instead of every agent opening its own connection (and its own prompt), the first agent starts a small background process that holds one connection, and every agent talks to it. You click Allow once each time Chrome starts.
• Each agent uses its own pre.dev API key, even though they share the connection.
• The cloud tools are pre.dev's hosted MCP tools, passed through on the same key, so they stay current without updating this package.
• Tabs open in the background by default and are kept responsive while an agent works in them, so you can keep using Chrome.
• Page loads count as done when the page is loaded and has stopped changing (or has been still for a second while images and ads finish), so results that scripts fill in are there when the agent reads.
• Links come back as the page's own address: sponsored redirects resolve to where they go, Amazon product links become /dp/<id>, and tracking parameters are removed.
• Snapshots reach into shadow DOM and same-origin iframes, and clicks are real mouse events, so modern web apps behave the way they do for you.
• Updates: the copy setup installs checks npm at most every 6 hours, checks the download against npm's checksum and swaps in the new files. Tool changes apply from the next call, with no new Chrome approval; the rare update that changes how the background process talks to Chrome waits until you run setup again. PREDEV_MCP_AUTO_UPDATE=off turns this off. npx -y @predotdev/mcp install-app installs or updates only that copy (no sign-in, no agent configs); the pre.dev CLI runs it for you.
• It has no dependencies: plain Node.js talking to Chrome's DevTools Protocol.

Safety

This tool drives your real, logged-in Chrome. Read this before you turn it on.

• Anything you can do in a tab, the agent can do. Only connect agents you trust, and keep an eye on what they do on sensitive sites. chrome_eval runs JavaScript in the page. A page can contain text written to steer an agent; the agent is told to treat page content as data, not instructions, but watch what it does after reading sites you don't trust.
• Passwords stay with you. It refuses to type into password fields (except on localhost and .test dev sites) and masks the values of password, card number, security code, one-time code and other secret-looking fields in snapshots. It won't attach or open SSH keys, cloud credentials, .env files, your saved pre.dev key or Chrome's own data files. The agent is told never to enter passwords, payment details or government ID numbers.
• It only listens on your machine. The background process binds to 127.0.0.1 only and rejects requests without a random per-run token, which is stored in a file only you can read. It also rejects any request that comes from a web page.
• What leaves your machine. Plain-words actions send pre.dev what that one action needs, and pre.dev's AI model reads it to answer: chrome_act sends your description, the page's headings and its interactive elements (role, name and field value, with the secret fields above masked); a plain-words chrome_wait sends the condition, the page title, its URL (with token-like query values removed), the interactive elements and up to about 8,000 characters of the page's visible text. The cloud tools send what you ask them to do. Every other Chrome tool runs locally, though your agent's own AI model sees what the tools return.
• Off switch. Run npx -y @predotdev/mcp stop to stop the background process, or turn remote debugging off at chrome://inspect/#remote-debugging.

Configuration

Set these in your agent's MCP config (env).

Variable	What it does
PREDEV_API_KEY	Your pre.dev API key. Overrides the key saved by login, which overrides your pre.dev CLI login.
PREDEV_MCP_CLOUD	off lists only the Chrome tools, without pre.dev's cloud tools.
PREDEV_API_URL	The pre.dev API to call. Default https://api.pre.dev.
PREDEV_MCP_AUTO_UPDATE	off stops the copy setup installs from updating itself from npm.
CHROME_MCP_USER_DATA_DIR	Use a different Chrome data folder, for example Chrome Beta or a separate Chrome you started yourself. Each folder gets its own background process.

State, logs, the stable copy setup installs and the key saved by login (readable only by you) are kept in ~/.predev/mcp/.

Commands

npx -y @predotdev/mcp setup      # add to every agent, connect to Chrome, sign in (optional; also updates)
npx -y @predotdev/mcp check      # check your setup, list your Chrome profiles, check your key
npx -y @predotdev/mcp login      # sign in to pre.dev again
npx -y @predotdev/mcp logout     # forget the saved key
npx -y @predotdev/mcp stop       # stop the background process (it restarts on the next tool call)
npx -y @predotdev/mcp uninstall  # remove it from every agent and delete its files

Troubleshooting

You see	Do this
Chrome remote debugging is off	Open chrome://inspect/#remote-debugging in Chrome and turn it on.
Chrome is asking "Allow remote debugging?"	Click Allow in Chrome, then ask your agent to try again.
Chrome asks to allow again	Normal after Chrome restarts. Updates keep the approved connection, except a rare one that changes how the background process talks to Chrome.
Plain-words actions need a pre.dev account	Run npx -y @predotdev/mcp login. No restart needed.
pre.dev rejected the saved key	Run npx -y @predotdev/mcp login again.
A message about credits or subscribing	Your workspace is out of trial credits. Subscribe or top up at pre.dev/billing.
Another server is already named predev	setup leaves it alone and registers this one as pre-dev.
You had the hosted pre.dev MCP or an older chrome install	setup replaced it; this server has all of its tools.
The agent can't start the server, or npx/node not found	Run setup: it registers full paths that work in desktop apps.
Codex says a tool call timed out	Set tool_timeout_sec = 900 (see the Codex setup).
codex exec says a tool call requires approval, but approval policy is never	Non-interactive Codex can't ask you, so allow the tools for that run: codex exec -c 'mcp_servers.predev.default_tools_approval_mode="approve"' "...".
Anything else	Run npx -y @predotdev/mcp check, and look at ~/.predev/mcp/predev-mcp.log.

Platform support

macOS is supported and tested. Linux and Windows are not tested yet. The code looks for Chrome's data in the standard places (~/.config/google-chrome and %LOCALAPPDATA%\Google\Chrome\User Data), and on those systems a profile needs an open Chrome window before the agent can use it. Reports and pull requests are welcome.

Development

git clone https://github.com/predotdev/mcp
cd mcp
node src/bridge.mjs check

Point your agent at node /path/to/mcp/src/bridge.mjs. Edits to src/tools.mjs reload automatically without dropping Chrome's approved connection: every call runs the calling copy's tools.mjs. The background process restarts (and Chrome asks you to allow again) only when PROTOCOL in src/bridge.mjs changes; bump it when you change the daemon's HTTP API, what it hands tools.mjs, or its Chrome connection code, or run node src/bridge.mjs stop to pick up other daemon edits.

About

Free and open source from pre.dev, built with the pre.dev CLI. Try it on your own project:

curl -fsSL https://pre.dev/install | bash

Want the same browser agents from your own code? Use the REST API and SDKs.

MIT licensed. See LICENSE.