JS Reverse MCP Server: Setup for Claude, Cursor and Other Apps

• Lists or switches browser tabs

  Lists the open pages or picks one as the target for later tools.

  Try: “Which tabs are open?”

  Read · select_page

• Opens a URL in a new tab

  Opens a separate browser page for a URL, reusing a blank start tab when there is one.

  Try: “Open https://example.com in a new tab.”

  Runs code · new_page

• Goes to a URL, reloads, or moves through history

  Navigates the selected page, which also triggers any breakpoints you set.

  Try: “Reload the page and watch for the login request.”

  Runs code · navigate_page

• Lists or picks an iframe

  Lists the frames in the page or selects one, so later click and script tools act inside it.

  Try: “Switch to the payment iframe.”

  Read · select_frame

• Takes a screenshot of the page

  Captures how the selected page looks, to check layout or the effect of a click.

  Try: “Take a screenshot of the page.”

  Read · take_screenshot

• Clicks one element

  Clicks a button, link or control chosen by CSS selector, in the selected frame.

  Try: “Click the Sign in button.”

  Write · click_element

• Runs JavaScript in the page

  Runs one JavaScript function against the page, its storage and globals, or a paused frame, and can process one local file.

  Try: “Read the value of window.__token.”

  Runs code · evaluate_script

• Reads the page's console output

  Returns console messages and uncaught errors captured for the page.

  Try: “Show the console errors.”

  Read · list_console_messages

• Lists the JavaScript loaded by the page

  Lists external, inline and eval scripts in the current frame.

  Try: “List all scripts loaded on this page.”

  Read · list_scripts

• Searches the page's code for text

  Finds a function name, endpoint, string or pattern across loaded scripts, including minified ones.

  Try: “Find where the sign function is defined.”

  Read · search_in_sources

• Reads a small part of a script

  Returns a small region of source around a match or a paused location, without running or pausing the page.

  Try: “Show the code around that match.”

  Read · get_script_source

• Saves a whole script to a file

  Saves one complete JavaScript or WASM source to your disk for inspection, for example a large minified bundle.

  Try: “Save the main bundle to a file.”

  Files · save_script_source

• Pauses the page at a line of code

  Sets a breakpoint where given code text appears, so you can see runtime values.

  Try: “Pause where the token is computed.”

  Write · set_breakpoint_on_text

• Pauses when a request is about to be sent

  Sets a breakpoint on a future XHR or fetch whose URL contains the text you give.

  Try: “Pause when the page calls /api/login.”

  Write · break_on_xhr

• Lists active breakpoints

  Returns the code and request breakpoints this session has set.

  Try: “What breakpoints are set?”

  Read · list_breakpoints

• Removes a breakpoint

  Removes one code or request breakpoint, or all of them after explicit confirmation.

  Try: “Remove all breakpoints.”

  Write · remove_breakpoint

• Shows where the page is paused

  Returns the call stack, source locations and scopes after a breakpoint or pause stops execution.

  Try: “Where is it paused and what are the variables?”

  Read · get_paused_info

• Pauses or resumes the page

  Pauses the page immediately or resumes it from a pause. It never toggles by itself.

  Try: “Resume execution.”

  Runs code · pause_or_resume

• Steps through the code one operation

  Advances one debugger step from a pause and shows the next source context.

  Try: “Step into the next call.”

  Runs code · step

• Lists captured web requests

  Shows HTTP traffic for the page with headers, bodies, redirects and cookie-setting responses. It can also export a request to a file you name.

  Try: “Show requests that set a cookie.”

  Files · list_network_requests

• Shows which code sent a request

  Traces the JavaScript that initiated a captured request, without pausing.

  Try: “What code sent request 12?”

  Read · get_request_initiator

• Clears the captured request log

  Discards captured traffic for the page after you confirm, for a clean capture window.

  Try: “Clear the network log, then I will click login.”

  Delete · clear_network_requests

• Reads WebSocket connections and messages

  Shows captured WebSocket connections and their frames.

  Try: “Show the WebSocket messages.”

  Read · get_websocket_messages

• Clears the site's cookies, cache and storage

  Irreversibly clears browser state for the page after you confirm, to replay a login from scratch.

  Try: “Clear site data and reload.”

  Delete · clear_site_data

Watch out for

• It runs JavaScript on pages you open

  The script tool runs code in the page with access to its storage and globals. Do not open sites you are not allowed to test. github.com

• Browser anti-detection is on by default

  The README (in Chinese) says the browser hides automation signals by default: it avoids Runtime.enable, removes automation launch flags, uses a real viewport and a Google referer. The optional --cloak mode targets sites using Cloudflare Turnstile, DataDome or FingerprintJS. This can get past bot protection, so use it only on sites you own or have permission to test. github.com

• The default profile keeps your logins

  A persistent profile keeps cookies and local storage, so sites you sign in to stay signed in. Use the isolated option for a clean throwaway browser. github.com

• Clearing site data cannot be undone

  The clear-site-data tool wipes cookies, cache and storage for the page after confirmation. Confirm only on test sites. github.com

• Stealth mode downloads a large binary

  The cloak option downloads about 200MB of browser binary on first start. Use it only if you accept that. github.com

• It saves files to your disk

  Script and request data can be saved locally for review. Check the paths before approving. github.com

Security advisories