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Create an MCP App

Source: R/mcp-app.R
mcp_app.Rd

Convenience function to create an McpApp object.

Usage

mcp_app(
  ui,
  tools = list(),
  name = "shinymcp-app",
  version = "0.1.0",
  theme = NULL,
  csp = NULL,
  permissions = NULL,
  prefers_border = NULL,
  tool_visibility = NULL,
  trigger = NULL,
  debounce_ms = NULL,
  resources = NULL,
  tool_outputs = NULL,
  ...
)

Arguments

ui

UI definition (htmltools tags). Can be a simple htmltools::tagList() of shinymcp components, or a full bslib::page() with theme.

tools

List of tools

name

App name

version

App version

theme

Optional bslib::bs_theme() object. Supports brand for brand.yml theming. Not needed if ui is already a bslib::page().

csp

Optional named list of Content Security Policy domain declarations for the app's ui:// resource, per the MCP Apps spec. MCP hosts apply a restrictive default policy that blocks all external network access and assets, so any domain your app loads from at runtime must be declared here. Fields (snake_case or spec camelCase):

  • connect_domains: origins for fetch/XHR/WebSocket requests

  • resource_domains: origins for scripts, styles, images, fonts

  • frame_domains: origins for nested iframes

  • base_uri_domains: allowed base-uri values

Apps with fully inlined assets (the shinymcp default) don't need this.

permissions

Optional named list of iframe permissions the app needs, e.g. list(camera = list()). Most apps don't need this.

prefers_border

Optional logical hint that the host should draw a border around the embedded app.

tool_visibility

Optional named list mapping tool names to MCP Apps visibility scopes (character vectors drawn from c("model", "app")). Use "app" for tools only the rendered UI should call (hidden from the model's tool list), "model" for tools the UI must not call. Unset tools are visible to both.

trigger

When the UI calls tools as inputs change: "debounce" (default) or "change". "submit"/"manual" only apply inside shinymcp's own Shiny host.

debounce_ms

Debounce interval in milliseconds (default 250).

resources

Optional named list of extra resources served alongside the app, readable from the UI via window.shinymcp.readResource(uri). Names are URIs; values are a string (static content), a function returning a string (evaluated on each read — useful for lazy-loading data instead of inlining it into the app HTML), or a list with fields content, mime_type (default "text/plain"), name, description, and meta. For example: resources = list("ui://my-app/data" = list(content = function() jsonlite::toJSON(mtcars), mime_type = "application/json"))

tool_outputs

Optional named list mapping tool names to the output ids they return, e.g. list(explore = c("scatter", "stats")). Declared tools get an auto-generated outputSchema (all properties are strings, with descriptions derived from the matching UI output types). Only declare tools that return a named list keyed by those output ids.

...

Additional arguments passed to McpApp$new()

Value

An McpApp object