Add an MCP endpoint to a Shiny app

mcp_endpoint() returns a Shiny app that answers MCP requests at path (default /mcp), so an MCP App can be deployed anywhere Shiny apps run: Posit Connect, Shiny Server, or shiny::runApp() on your own machine. Deploy it like any Shiny app, then point MCP clients at https://<server>/<app-path>/mcp.

Given an McpApp (or a list of them), browsers visiting the app get the same preview page as preview_app().
Given a Shiny app and apps, browsers get the Shiny app and MCP clients get the apps. One deployment serves people and models; the apps can share the Shiny app's UI and functions.
Given a Shiny app alone, browsers still get the Shiny app, and the endpoint serves it, live, to MCP clients through as_mcp_app().

Clients that speak the stateless MCP revision (2026-07-28) can reach any of several R processes behind a load balancer. Live Shiny apps keep each view's session in the process that opened it; see as_mcp_app() for what happens when a request lands elsewhere.

On Posit Connect the endpoint sits behind the content's access controls, and mcp_request() reports the signed-in user.

Usage

mcp_endpoint(
  x,
  apps = NULL,
  path = "/mcp",
  allowed_origins = NULL,
  allowed_hosts = NULL,
  preview = TRUE,
  ...
)

Arguments

x: An McpApp, a list of apps, or a Shiny app.
apps: When x is a Shiny app, the apps to serve to MCP clients next to it: an McpApp or a list of them. Without apps, the Shiny app itself is served, live.
path: Endpoint path.
allowed_origins: Browser origins, besides the app's own, allowed to call the endpoint. See serve().
allowed_hosts: Host names the app is reached at, when it runs somewhere other than Posit Connect, shinyapps.io, or Shiny Server (for example in a container behind your own proxy). Elsewhere, requests for host names other than localhost or an IP address are refused; see serve().
preview: For apps, whether browsers get a preview page at /.
...: Passed to as_mcp_app() when x is a Shiny app served live.

Value

A Shiny app object.

Shiny's own MCP support

Shiny is gaining MCP support of its own (https://github.com/rstudio/shiny/pull/4407). Once it is released, it will be the way to put a live Shiny app in a chat, and shinymcp will stop serving live apps. as_mcp_app(), mcp_endpoint(), and mcp_tool_module() will take only apps built from tools, and bindMcp() and the helpers for server functions (mcp_model_context(), mcp_host_context(), and the rest) will be removed. For something the model should be able to use on its own, rewrite that part of the app as tools with mcp_app(); see vignette("rewriting-as-tools").

Examples

if (FALSE) { # \dontrun{
# app.R, deployed to Posit Connect with rsconnect::deployApp()
library(shinymcp)

app <- mcp_app(ui, tools = list(summarize_dataset), name = "datasets")
mcp_endpoint(app)

# A Shiny app for people, and an app built from tools for chat clients
library(shiny)
shinyApp(ui, server) |> mcp_endpoint(apps = app)

# A Shiny app, served live to chat clients and as usual to browsers
shinyApp(ui, server) |> mcp_endpoint(name = "explorer")
} # }

Usage

Arguments

Value

Shiny's own MCP support

See also

Examples