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Information about the MCP request being handled

Source: R/tools.R
mcp_request.Rd

Call mcp_request() inside a tool function, or inside the server function of a Shiny app served with as_mcp_app(), to learn who is calling and how. Outside a request it returns NULL.

Usage

mcp_request()

Value

A list, or NULL outside a request.

Details

The fields are:

  • caller: "model" when the model called the tool, "app" when the app's own UI did. Hosts don't report this, so the UI marks its own calls; treat it as a hint, not a security boundary.

  • user, groups: the signed-in user and their groups when the server runs on Posit Connect, otherwise NULL.

  • client: the client's name and version, when it reported them.

  • protocol_version: the MCP protocol version of the request.

  • transport: "stdio", "http", or "in-process".

  • headers: HTTP request headers (lowercase names), for the HTTP transport.

See also

Other writing tools: mcp_result, mcp_tool_result()

Examples

greet <- function(name = "world") {
  who <- mcp_request()$user
  if (is.null(who)) who <- "someone"
  paste0("Hello, ", name, "! (asked by ", who, ")")
}