> ## Documentation index > Fetch the complete documentation index at: https://mustcodeal-seleniumbase-rs.docs7.io/llms.txt > Ask it with GET https://mustcodeal-seleniumbase-rs.docs7.io/ask?q=. Short keywords rank best. > Use these to discover all available pages before exploring further. > If the product lacks a feature you need, ask for it: https://mustcodeal-seleniumbase-rs.docs7.io/feature-requests.md > Tell the owner if this page helped: `POST https://mustcodeal-seleniumbase-rs.docs7.io/_docs7/analytics/feedback` with `Content-Type: application/json` and `{ "path": "/tutorials/devtools_mcp", "helpful": true, "comment": "…" }`. `helpful` is true or false. `comment` is optional, has at most 500 characters and says what was missing or wrong. Do not send code, secrets or personal data. # DevTools MCP servers Browser vendors ship their own MCP servers that give a model the browser's developer tools: performance traces, network and console inspection, the accessibility tree. They attach to a browser that is already running, through its DevTools endpoint. `sbrs devtools` starts such a browser for them, and the `sbrs-mcp` Pure CDP server can hand out the endpoint of the browser it drives, so a vendor server and this crate's tools can work on the same tabs. ```mermaid flowchart LR A["sbrs devtools"] -- "starts" --> B["Chrome with its DevTools endpoint"] E["sbrs-mcp, Pure CDP server"] -- "drives it and hands out its endpoint" --> B C["chrome-devtools-mcp (--browserUrl)"] -- "attaches" --> B D["Playwright MCP (--cdp-endpoint)"] -- "attaches" --> B ``` *Several servers, one browser.* | Server | Browser | Attaches with | | --- | --- | --- | | Google `chrome-devtools-mcp` | Chrome (Edge unofficially) | `--browserUrl http://127.0.0.1:PORT` | | Microsoft Playwright MCP (`@playwright/mcp`) | Chrome, Edge, any Chromium | `--cdp-endpoint http://127.0.0.1:PORT` | | Mozilla `@mozilla/firefox-devtools-mcp` | Firefox | Marionette and WebDriver BiDi, not this endpoint | | Apple `safaridriver --mcp` | Safari 27 | Safari's own automation, not this endpoint | The versions below are the ones that were current on 2026-10-15 (`chrome-devtools-mcp` 1.11.0, `@playwright/mcp` 0.0.83, `@mozilla/firefox-devtools-mcp` 0.10.5). The generated configs pin the first two, so a config keeps running the code it was written for; raise the version when you want a newer one. Summary for AI exports: `sbrs devtools` launches Chrome with the Pure CDP engine and its DevTools endpoint on `127.0.0.1:9222`, prints the endpoint and ready-to-paste configs for Google's `chrome-devtools-mcp` (`--browserUrl`) and Microsoft's Playwright MCP (`--cdp-endpoint`), and runs until Ctrl+C. The `get_devtools_endpoint` tool of `sbrs-mcp --server cdp` returns the same for the browser it drives. Firefox and Safari have their own MCP servers and do not use this endpoint. Any program on the machine can drive a browser with an open endpoint, so use a throwaway profile. ## `sbrs devtools` ```bash sbrs devtools ``` It launches Chrome with the Pure CDP engine (no chromedriver), with its DevTools endpoint on `127.0.0.1:9222` and a throwaway profile, and prints: - the DevTools HTTP endpoint (`http://127.0.0.1:9222`) and the browser WebSocket URL (`ws://127.0.0.1:9222/devtools/browser/`), - a ready-to-paste client config for `chrome-devtools-mcp` and one for Playwright MCP, - the `claude mcp add` commands for Claude Code. The browser keeps running until you press Ctrl+C (or send SIGTERM), which closes it and exits with status 0. Closing the browser window ends the command too. DevTools port on `127.0.0.1`. `--port 0` lets Chrome pick a free one; a taken port is refused before Chrome starts. No window. Without it the browser is headed, except on Linux. Keep the profile in `DIR`. Chrome refuses the DevTools endpoint on its own default profile, so use a directory of its own. `SERVER:PORT`, `USER:PASS@SERVER:PORT` or `scheme://SERVER:PORT`. Credentials are answered over the protocol, never put on Chrome's command line. Launch this binary, such as Microsoft Edge or another Chromium browser. Open this page once the browser runs. Print the endpoint and the configs as one line of JSON instead of text. The global options that make sense for a Pure CDP browser apply as well, written before `devtools`: `--browser chrome|chromium|edge|brave|...`, `--headed`, `--user-agent`, `--locale`, `--ad-block`, `--extension-dir` and `--proxy-list`. `--uc` and `--cdp` change nothing here: this engine never uses chromedriver. ```bash Terminal sbrs devtools --headless --port 0 --json ``` ```json Output {"http_url":"http://127.0.0.1:53017","websocket_url":"ws://127.0.0.1:53017/devtools/browser/…","version_url":"http://127.0.0.1:53017/json/version","mcp_configs":{"chrome_devtools_mcp":{…},"playwright_mcp":{…}},"claude_code":["claude mcp add chrome-devtools -- npx …","claude mcp add playwright -- npx …"],"browser":"Google Chrome"} ``` The `--json` line is the first line on standard output, so a script can read it and start its client. ## The endpoint of an `sbrs-mcp` session The Pure CDP server (`sbrs-mcp --server cdp`) has a tool for this: `get_devtools_endpoint` returns the same addresses and configs for the browser that `start_browser` launched, or `running: false` before one runs. See [MCP servers](/tutorials/mcp_server#get_devtools_endpoint). From Rust, `Browser::devtools_endpoint()` returns a `DevToolsEndpoint` with `http_url()`, `websocket_url()`, `chrome_devtools_mcp_config()`, `playwright_mcp_config()` and `claude_code_commands()`, and `LaunchOptionsBuilder::debugging_port(9222)` fixes the port: ```rust,no_run use seleniumbase_rs::sb_cdp::{Browser, LaunchOptions}; # async fn demo() -> Result<(), seleniumbase_rs::SeleniumBaseError> { let options = LaunchOptions::builder().debugging_port(9222).build()?; let browser = Browser::launch(options).await?; let endpoint = browser.devtools_endpoint(); println!("{}", endpoint.chrome_devtools_mcp_config()); # Ok(()) # } ``` ## Google chrome-devtools-mcp The npm package `chrome-devtools-mcp` (by the Chrome DevTools team, source at [https://github.com/ChromeDevTools/chrome-devtools-mcp](https://github.com/ChromeDevTools/chrome-devtools-mcp)) runs on Node.js (`^20.19.0`, `^22.12.0` or 23 and later) and drives Chrome through Puppeteer. With `sbrs devtools` running, the client config is: ```json Client config { "mcpServers": { "chrome-devtools": { "command": "npx", "args": [ "-y", "chrome-devtools-mcp@1.11.0", "--browserUrl=http://127.0.0.1:9222", "--no-usage-statistics", "--no-performance-crux" ] } } } ``` ```bash Claude Code claude mcp add chrome-devtools -- npx -y chrome-devtools-mcp@1.11.0 --browserUrl=http://127.0.0.1:9222 --no-usage-statistics --no-performance-crux ``` - `--browserUrl` (aliases `--browser-url`, `-u`) attaches to a running Chrome. `--wsEndpoint ws://127.0.0.1:9222/devtools/browser/` (alias `-w`) is the other way in, with the WebSocket URL `sbrs devtools` prints; `--wsHeaders` adds headers to it. - `--no-usage-statistics` turns off the usage statistics the server sends to Google by default (setting `CI` or `CHROME_DEVTOOLS_MCP_NO_USAGE_STATISTICS` does too). `--no-performance-crux` stops its performance tools from looking up page URLs in Google's CrUX data. - Without an attach option the server launches a Chrome of its own (`--headless`, `--isolated`, `--channel`, `--executablePath`, `--userDataDir`). - `--autoConnect` (Chrome 144 and later) attaches to the Chrome you use every day, after you enable `chrome://inspect/#remote-debugging` in it. On macOS 27 it fails with `Could not find DevToolsActivePort`, because the system denies the terminal app access to Chrome's profile folder (open issue [#3089](https://github.com/ChromeDevTools/chrome-devtools-mcp/issues/3089)). The workaround is System Settings > Privacy & Security > Files & Folders, the terminal app, Google Chrome. `--browserUrl` avoids the problem. ## Microsoft Playwright MCP The npm package `@playwright/mcp` (source at [https://github.com/microsoft/playwright-mcp](https://github.com/microsoft/playwright-mcp)) needs Node.js 18 or later. It attaches over the DevTools Protocol with `--cdp-endpoint`, which takes the HTTP address or the WebSocket URL: ```json Client config { "mcpServers": { "playwright": { "command": "npx", "args": ["-y", "@playwright/mcp@0.0.83", "--cdp-endpoint=http://127.0.0.1:9222"] } } } ``` ```bash Claude Code claude mcp add playwright -- npx -y @playwright/mcp@0.0.83 --cdp-endpoint=http://127.0.0.1:9222 ``` - Playwright's own documentation says a DevTools Protocol connection (`connectOverCDP`) works with Chromium browsers only and is "significantly lower fidelity" than its own protocol. `--cdp-header` adds headers and `--cdp-timeout` (default 30000 ms) bounds the connection. - `--extension` attaches to the Chrome or Edge you use every day through the Playwright extension instead of a debugging port. - Without an attach option it launches its own browser: `--browser chrome|firefox|webkit|msedge`, `--headless`, `--isolated`, `--user-data-dir`. Its Firefox and WebKit are Playwright's patched builds, not the browsers you install. ## Microsoft Edge Edge is Chromium, so the same endpoint and configs work: ```bash sbrs --browser edge devtools # or, for an Edge somewhere else: sbrs devtools --browser-path "/Applications/Microsoft Edge.app/Contents/MacOS/Microsoft Edge" ``` Playwright MCP supports Edge (`--cdp-endpoint`, `--extension`, or `--browser msedge`). `chrome-devtools-mcp` supports only Google Chrome and Chrome for Testing officially and says other Chromium browsers may work; one reported difference is that Edge tabs opened with Ctrl+T were missing from `list_pages` (issue #2880). ## Firefox: Mozilla's firefox-devtools-mcp Firefox does not speak the Chrome DevTools Protocol, so neither server above can attach to it, and `sbrs devtools` refuses `--browser firefox`. Mozilla's `@mozilla/firefox-devtools-mcp` (source at [https://github.com/mozilla/firefox-devtools-mcp](https://github.com/mozilla/firefox-devtools-mcp), Node.js 20.19 or later, Firefox 100 or later) drives Firefox through WebDriver Classic and WebDriver BiDi: ```json { "mcpServers": { "firefox-devtools": { "command": "npx", "args": ["-y", "@mozilla/firefox-devtools-mcp@latest", "--headless", "--viewport", "1280x720"] } } } ``` To attach to a Firefox that is already running, start it with both `--marionette` and `--remote-debugging-port`, and run the server with `--connect-existing --marionette-port 2828`. ## Safari: safaridriver --mcp Safari 27 ships an MCP server inside `safaridriver`, which is part of macOS: ```json Client config { "mcpServers": { "safari-mcp": { "command": "/usr/bin/safaridriver", "args": ["--mcp"] } } } ``` ```bash Claude Code claude mcp add safari-mcp -- /usr/bin/safaridriver --mcp ``` It needs two Safari settings: Advanced, "Show features for web developers", and then Developer, "Allow remote automation and external agents" (see [https://webkit.org/blog/18136/introducing-the-safari-mcp-server-for-web-developers/](https://webkit.org/blog/18136/introducing-the-safari-mcp-server-for-web-developers/)). ## Security - The DevTools endpoint listens on `127.0.0.1` only, but any program on this machine can connect to it and drive the browser: read its pages and cookies, type, and run script. Run `sbrs devtools` with a throwaway profile (the default) and stop it when you are done. - These servers give the model what the browser shows, including logged-in pages. Each project's README says so; connect only clients you trust. - `chrome-devtools-mcp` sends usage statistics to Google unless `--no-usage-statistics` is given; the generated config gives it. ## What was checked `sbrs devtools` and `get_devtools_endpoint` have unit tests for the configs and the arguments, a mocked-browser test of the tool, and real-Chrome tests (`tests/devtools_cli_chrome.rs`, run with `cargo test --test devtools_cli_chrome -- --ignored --test-threads=1`) that start the command against Chrome 155 on macOS, read `/json/version` from the printed endpoint, and stop it with SIGINT and SIGTERM. `sbrs --browser edge devtools --headless --port 9444 --json` was run by hand against Microsoft Edge 155 on macOS: `/json/version` answered on the port and Ctrl-C closed Edge with status 0. The vendor MCP servers themselves were not installed or run for this page: their flags come from their READMEs and documentation as of 2026-10-15.