Bridge quickstart
Make your first live tool call
This path uses the WebMCP Today extension in your existing supported Chromium browser and a local MCP bridge. It keeps package installation and destructive confirmations in the browser and does not replace missing tools with browser automation.
Before Step 1: this first-party local bridge requires macOS and Chrome or Brave, plus Node 20 or newer or Bun for the MCP bridge.
WebMCP Today is in public beta. The extension, bridge, and package format may change while the platform develops. Report a failed step through the project's GitHub issues.
Checking for the WebMCP Today extension…
Step 1
Load WebMCP Today in your browser
Download the WebMCP Today extension ZIP and extract it. Then open the browser's extensions page, enable Developer mode, choose Load unpacked, and select the extracted folder. The extension must remain enabled in the same browser that will hold your target tab.
curl -L https://github.com/robertn702/webmcp-today/releases/latest/download/webmcp-today-extension.zip -o ~/Downloads/webmcp-today-extension.zip unzip ~/Downloads/webmcp-today-extension.zip -d ~/Downloads/webmcp-today-extension
Prefer a manual download? Use the latest release on GitHub instead.
Step 2
Install the MCP bridge and configure your client
Add the published MCP bridge to your MCP client with the pinned npx command below. It downloads the bridge on demand without a global installation. After restarting the client, ask it to callsetup_webmcp_bridge with {"browser":"chrome","confirm":true}(or use brave). The confirmation-gated tool copies the durable host and writes only this bridge's per-user native-messaging manifest; it does not expose an HTTP service.
Select your MCP client, then add the local server without replacing your other MCP servers:
Add this to opencode.json:
{
"$schema": "https://opencode.ai/config.json",
"mcp": {
"webmcp-today": {
"type": "local",
"command": ["npx", "--yes", "@webmcp-today/mcp-bridge@0.3.0"]
}
}
}Restart or reload your MCP client, then call get_webmcp_bridge_status after setup and continue only when it reports ready. The server exposes list_connected_webmcp_tabs, list_webmcp_tools, and execute_webmcp_tool. The webpage cannot see a native host or MCP client: the successful tab-list call is the real handoff check.
Step 3
Open Reddit and explicitly install its package
In your normal browser, open https://www.reddit.com/r/webdev/ and make that tab visible and selected. Open the WebMCP Today extension popup, inspect the suggested Reddit package, and click Install. This remains a browser-owned consent action; your agent cannot perform it for you. The extension registers the package into the already open matching tab.
If tools are missing, install or repair the package from the popup and list the tools again. Do not substitute DOM scraping or arbitrary page execution for a missing tool.
Step 4
List live tools and make the read-only call
Ask the MCP client to list connected tabs, then list the tools in the selected Reddit tab. A successful installed package contributes 6 Reddit tools, includingreddit_subreddit_hot. Call it with {"subreddit":"webdev","limit":5}, passing the document and tools generations returned from the tool-list call.
Use the WebMCP Today MCP server to verify a live, read-only Reddit call.
1. I have selected the normal browser tab at https://www.reddit.com/r/webdev/.
2. Call list_connected_webmcp_tabs, then list_webmcp_tools for that tab.
3. If reddit_subreddit_hot is missing, ask me to open the WebMCP Today extension popup, inspect the suggested Reddit package, and click Install. Wait for my confirmation, then list tools again in the same tab.
4. Call execute_webmcp_tool with the tab id, document generation, tools generation, and reddit_subreddit_hot origin returned by list_webmcp_tools. Pass reddit_subreddit_hot as toolName and {"subreddit":"webdev","limit":5} as input.
5. Show five returned titles and permalinks.
Do not substitute DOM scraping or arbitrary page execution for the missing tool.Success: five current post titles and permalinks return from Reddit's own JSON API. This is generic WebMCP tool passthrough: the bridge lists and executes whatever live tools are registered in the selected tab — via Chrome's native API or the extension's built-in fallback. It never fabricates tools or substitutes browser automation.
Next: create a package
A first call proves the browser bridge. To add a capability for another site, start with the package format and one read-only API tool.
Read the package format