Struct WebMCP 

pub struct WebMCP { /* private fields */ }

The tools a page registers through the experimental WebMCP browser API, so a test can list and call them as an agent would.

Reached through Page::webmcp (the main frame’s tools) or Frame::webmcp.

The API is behind a flag in every browser that has it. Launch Chromium with --enable-features=WebMCP in args, or Firefox with the dom.modelcontext.enabled and dom.modelcontext.testing.enabled preferences set in firefox_user_prefs. Without them, tools fails with WebMCP is not enabled, followed by how to enable it; WebKit does not support it at all and fails with WebMCP is not supported in WebKit.

Example

use playwright_rs::LaunchOptions;
use playwright_rs::protocol::Playwright;

let playwright = Playwright::launch().await?;
let browser = playwright
    .chromium()
    .launch_with_options(LaunchOptions::new().args(vec!["--enable-features=WebMCP".into()]))
    .await?;
let page = browser.new_page().await?;
page.goto("https://example.com/app", None).await?;

for tool in page.webmcp().tools(None).await? {
    println!("{}: {}", tool.name, tool.description);
}
let sum: serde_json::Value = page
    .webmcp()
    .call_tool("add", &serde_json::json!({ "a": 2, "b": 40 }), None)
    .await?;

See: https://playwright.dev/docs/api/class-webmcp

Implementations

impl WebMCP

pub async fn tools( &self, options: impl Into<Option<WebMCPOptions>>, ) -> Result<Vec<WebMCPTool>>

Lists the tools the frame’s page has registered, in the browser’s order.

Errors

Returns error if WebMCP is not enabled in this browser (see the type docs), or the frame has been detached.

See: https://playwright.dev/docs/api/class-webmcp#webmcp-tools

pub async fn call_tool<I, R>( &self, name: &str, input: &I, options: impl Into<Option<WebMCPOptions>>, ) -> Result<R>

where I: Serialize + ?Sized, R: DeserializeOwned,

Calls the tool registered as name with input, and returns what it returned, deserialized as R (use serde_json::Value to take it as it is). A tool reports its own failure in its result, with isError set, rather than raising one, so such a result comes back like any other.

input is serialized the way an evaluate argument is; pass &() for a tool that takes none.

Errors

Returns error if no tool is registered as name (No WebMCP tool named "..."), WebMCP is not enabled, or the result does not deserialize as R.

See: https://playwright.dev/docs/api/class-webmcp#webmcp-call-tool

Trait Implementations

impl Clone for WebMCP

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WebMCP

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.