YetiBrowser MCP

# YetiBrowser MCP YetiBrowser MCP is a fully open-source implementation of the Browser MCP workflow. It links a Node-based MCP server with Chrome/Firefox extensions so Model Context Protocol clients—Codex/Claude Code, Cursor, Windsurf, MCP Inspector, or your own tools—can automate a real browser tab while keeping every byte on your machine and auditable. ## Why pick YetiBrowser MCP? - **Transparent and hackable** – no blob downloads. Inspect, fork, and extend every component. - **Local-first** – the extension talks only to a localhost MCP server; browsing data never leaves your device. - **Cross-browser** – shared logic powers both Chrome and Firefox packages (Firefox build is pending better Manifest V3 support, so connection UX may be limited until Mozilla ships full MV3 APIs). - **Developer-focused tooling** – richer console capture, DOM diffing, page-state dumps, and full-page screenshots built for debugging and QA. - **Production-friendly** – scripts and docs for packaging, publishing, and integrating with IDE workflows. ### Repository layout - `packages/shared` – shared TypeScript definitions for messages and tool schemas. - `packages/server` – the MCP server that bridges MCP clients to a running browser tab. - `extensions/shared` – shared extension source (background/popup) and assets. - `extensions/chrome` / `extensions/firefox` – per-browser packaging layers. - `docs/` – workspace commands, publishing checklists, and feature notes. - `scripts/` – helper utilities such as `package-extensions.sh` for release zips. ## MCP Tools Available - `browser_snapshot` – capture an accessibility-oriented snapshot of the current page - `browser_snapshot_diff` – compare the two most recent snapshots to highlight DOM/ARIA changes - `browser_navigate` – load a new URL in the connected tab and return an updated snapshot - `browser_go_back` / `browser_go_forward` – move through history while keeping MCP in sync - `browser_wait` – pause automation for a set number of seconds - `browser_press_key` – simulate a keyboard key press on the focused element - `browser_click` – click the element identified by a CSS selector - `browser_hover` – hover the pointer over the targeted element - `browser_type` – type text (optionally submitting with Enter) into an editable element - `browser_select_option` – choose one or more options in a `<select>` element - `browser_screenshot` – capture a viewport or full-page screenshot via the DevTools protocol - `browser_get_console_logs` – return recent console output, including errors with stack traces - `browser_page_state` – dump forms, storage keys, and cookies for the connected page - `browser_connection_info` – report bridge WebSocket port, connection status, and extension version ## MCP Browser Extension Installation ### Chrome Browser - Install the latest Chrome Browser Extension here: https://chromewebstore.google.com/detail/hpedknkjljpopinabjjmljgckhlancni?utm_source=item-share-cb - Leave it on **Automatic** connection mode unless you are running multiple instances of YetiBrowser MCP Server ### Firefox Browser (not currently available) - Due to the limited capabilities of Manifest v3 in Firefox stable release, the Firefox extension is on hold until full support is commonly avaialble (outside of Nightly builds). ## MCP Server Installation ### Codex CLI - Edit your ~/.codex/config.toml and add the MCP entry: ```toml [mcp_servers.yetibrowser-mcp] command = "npx" args = ["yetibrowser-mcp"] ``` - Restart `codex` CLI command; you should see `yetibrowser-mcp` listing under `/mcp` tools. - If you want to provide a specific port, use this format for the args entry: `args = ["yetibrowser-mcp", "--ws-port", "9010"]` ### Claude Code - Make sure the extension is installed and connected to a tab, then start the MCP server with `npx yetibrowser-mcp` (or run the locally built CLI). - Add the server entry to `~/Library/Application Support/Claude/claude_desktop_config.json` (see the example in [`docs/publishing.md`](docs/publishing.md)). - Restart `claude` so it picks up the new MCP server; you should see `yetibrowser-mcp` listed under the `/mcp` tools menu once the extension connects. ### Other MCP-aware clients - Any MCP client can connect by spawning the CLI (`npx yetibrowser-mcp`) or optionally provide a specific port, e.g. `npx yetibrowser-mcp --ws-port 9010`. - The server exposes the standard MCP transport over stdio, so use whatever configuration mechanism your client supports to run the command above when a tab is connected. ### MCP Inspector - For testing and debugging outside a coding agent. - `npx @modelcontextprotocol/inspector yetibrowser-mcp -- --ws-port 9010` to run and inspect the MCP server in conjunction with the YetiBrowser MCP browser extension. ### Troubleshooting - The CLI walks ports `9010-9020` until it finds a free one, logging `switched to` when it advances. Pass `--ws-port <port>` if you want to pin a specific port instead. - The Browser extension popup mirrors that behaviour: leave it on “Automatic” to track the CLI’s port, or choose “Manual” and enter the port reported by `browser_connection_info` / the CLI log to override it. - Simply ask your AI tool about the connection port. For example: `what is the yetibrowser mcp connction info?`, then set the manual port the port reported. ## Documentation & build scripts - Workspace commands live in [`docs/workspace-commands.md`](docs/workspace-commands.md). - Publishing steps (npm + extension stores) are in [`docs/publishing.md`](docs/publishing.md). - Screenshot behaviour is documented in [`docs/screenshot.md`](docs/screenshot.md). - Generate distributable Chrome/Firefox zips with `./scripts/package-extensions.sh` (outputs to `artifacts/`). - A repository-level privacy policy is available in [`PRIVACY.md`](PRIVACY.md).