Add support for prompts

DESCRIPTION

@@ -6,9 +6,10 @@ Maintainer: Bulent Arman Aksoy <arman@aksoy.org>
 Authors@R: 
     person("Bulent Arman", "Aksoy", , "arman@aksoy.org", role = c("aut", "cre"))
 Description: Extends plumber APIs with Model Context Protocol (MCP) support,
-    enabling AI assistants to discover and call your API endpoints as tools.
+    enabling AI assistants to discover and call your API endpoints as tools,
+    read resources for context, and use prompt templates for guided interactions.
     Simply add pr_mcp() to your plumber pipeline to automatically expose all
-    endpoints via the MCP protocol.
+    endpoints via the MCP protocol with rich schema generation and documentation.
 License: MIT + file LICENSE
 Encoding: UTF-8
 Roxygen: list(markdown = TRUE)

NEWS.md

@@ -0,0 +1,93 @@
+# plumber2mcp 0.3.0
+
+## New Features
+
+### Prompts Support
+* Added full MCP Prompts support allowing you to define reusable prompt templates that AI assistants can discover and use
+* New `pr_mcp_prompt()` function to register prompt templates with your MCP server
+* Prompts support optional arguments with required/optional parameters
+* Prompts can return simple strings, structured messages, or multi-turn conversations
+* Both HTTP and stdio transports fully support prompts
+* Added `prompts/list` and `prompts/get` JSON-RPC handlers
+* Updated `initialize` response to advertise prompts capability
+
+### Enhanced Testing
+* Added comprehensive edge case testing (24 new tests)
+* Added integration tests for combined features (10 new tests)
+* Added security and validation tests (18 new tests)
+* Total test count increased from ~69 to ~121 tests (75% increase)
+* Tests now cover error handling, malformed inputs, injection attacks, and real-world scenarios
+
+## Improvements
+
+* Enhanced schema generation now includes output schemas
+* Better error handling for malformed JSON-RPC requests
+* Improved handling of NULL, NA, and empty values
+* More robust handling of complex nested data structures
+* Added support for functions with req/res parameters
+
+## Documentation
+
+* Comprehensive README updates with prompts examples and use cases
+* Added example file demonstrating prompts usage (inst/examples/prompts_example.R)
+* Detailed documentation of prompt message formats
+* Added use cases for workflow guidance, code generation, and domain-specific assistance
+
+## Bug Fixes
+
+* Fixed parameter ordering in stdio transport handlers
+* Fixed JSON-RPC error responses for unknown methods
+* Improved type mapping for plumber parameters
+
+# plumber2mcp 0.2.0
+
+## New Features
+
+### Resources Support
+* Added MCP Resources support for exposing R content to AI assistants
+* New `pr_mcp_resource()` function to add custom resources
+* New `pr_mcp_help_resources()` convenience function for R help topics
+* Resources can provide documentation, data summaries, session info, and more
+* Added `resources/list` and `resources/read` handlers
+
+### Stdio Transport
+* Added native stdio transport support for standard MCP clients
+* New `pr_mcp_stdio()` function for stdio-based servers
+* Compatible with mcp-cli, Claude Desktop, and other MCP clients
+* Handles JSON-RPC over stdin/stdout
+
+## Improvements
+
+* Enhanced schema generation with rich descriptions from roxygen comments
+* Automatic detection of required vs optional parameters
+* Improved type inference for function parameters and return values
+* Better handling of empty properties (serialize as object, not array)
+
+## Documentation
+
+* Comprehensive README with examples for all transport types
+* Added resources examples and documentation
+* Added MCP Inspector testing instructions
+
+# plumber2mcp 0.1.0
+
+## Initial Release
+
+### Core Features
+* HTTP transport for MCP protocol
+* Automatic endpoint discovery from Plumber APIs
+* JSON-RPC 2.0 protocol implementation
+* Tool schema generation from function signatures
+* Support for include/exclude endpoint filters
+* Customizable server name, version, and mount path
+
+### MCP Protocol Support
+* `initialize` - Server initialization and capabilities
+* `tools/list` - List available API endpoints as tools
+* `tools/call` - Execute API endpoints through MCP
+* `ping` - Server health check
+
+### Documentation
+* Basic README with installation and usage
+* Example Plumber API files
+* GitHub Actions CI/CD setup

R/plumber2mcp-package.R

@@ -0,0 +1,179 @@
+#' @keywords internal
+"_PACKAGE"
+
+#' plumber2mcp: Add Model Context Protocol Support to Plumber APIs
+#'
+#' @description
+#' The plumber2mcp package extends Plumber APIs with Model Context Protocol (MCP)
+#' support, enabling AI assistants (like Claude, ChatGPT, etc.) to discover and
+#' interact with your R functions through three key MCP primitives:
+#'
+#' \itemize{
+#'   \item \strong{Tools}: AI assistants can call your API endpoints directly
+#'   \item \strong{Resources}: AI assistants can read documentation, data, and analysis results
+#'   \item \strong{Prompts}: AI assistants can use pre-defined templates to guide interactions
+#' }
+#'
+#' @section Main Functions:
+#'
+#' \strong{Core MCP Setup:}
+#' \itemize{
+#'   \item \code{\link{pr_mcp}}: Add MCP support to a Plumber router (main function)
+#'   \item \code{\link{pr_mcp_http}}: Add MCP support with HTTP transport
+#'   \item \code{\link{pr_mcp_stdio}}: Add MCP support with stdio transport
+#' }
+#'
+#' \strong{Resources:}
+#' \itemize{
+#'   \item \code{\link{pr_mcp_resource}}: Add a custom resource
+#'   \item \code{\link{pr_mcp_help_resources}}: Add built-in R help resources
+#' }
+#'
+#' \strong{Prompts:}
+#' \itemize{
+#'   \item \code{\link{pr_mcp_prompt}}: Add a prompt template
+#' }
+#'
+#' @section Quick Start:
+#'
+#' \strong{HTTP Transport (for testing):}
+#' \preformatted{
+#' library(plumber)
+#' library(plumber2mcp)
+#'
+#' pr("plumber.R") \%>\%
+#'   pr_mcp(transport = "http") \%>\%
+#'   pr_run(port = 8000)
+#' }
+#'
+#' \strong{Stdio Transport (for MCP clients):}
+#' \preformatted{
+#' library(plumber)
+#' library(plumber2mcp)
+#'
+#' pr("plumber.R") \%>\%
+#'   pr_mcp(transport = "stdio")
+#' }
+#'
+#' @section Adding Features:
+#'
+#' \strong{Add a Resource:}
+#' \preformatted{
+#' pr \%>\%
+#'   pr_mcp(transport = "stdio") \%>\%
+#'   pr_mcp_resource(
+#'     uri = "/data/summary",
+#'     func = function() summary(mtcars),
+#'     name = "Dataset Summary"
+#'   )
+#' }
+#'
+#' \strong{Add a Prompt:}
+#' \preformatted{
+#' pr \%>\%
+#'   pr_mcp(transport = "stdio") \%>\%
+#'   pr_mcp_prompt(
+#'     name = "analyze-data",
+#'     description = "Guide for data analysis",
+#'     arguments = list(
+#'       list(name = "dataset", description = "Dataset name", required = TRUE)
+#'     ),
+#'     func = function(dataset) {
+#'       paste("Please analyze the", dataset, "dataset")
+#'     }
+#'   )
+#' }
+#'
+#' @section MCP Protocol:
+#'
+#' This package implements the Model Context Protocol (MCP) specification version
+#' 2024-11-05. It provides:
+#'
+#' \itemize{
+#'   \item \strong{Automatic endpoint discovery}: Scans your Plumber API and converts endpoints to MCP tools
+#'   \item \strong{Rich schema generation}: Creates detailed JSON schemas from roxygen documentation
+#'   \item \strong{JSON-RPC 2.0}: Handles all MCP communication via JSON-RPC
+#'   \item \strong{Multiple transports}: HTTP (for testing) and stdio (for MCP clients)
+#'   \item \strong{Enhanced documentation}: Extracts parameter descriptions, types, and defaults
+#' }
+#'
+#' @section Supported MCP Methods:
+#'
+#' \strong{Core Protocol:}
+#' \itemize{
+#'   \item \code{initialize}: Server initialization and capability negotiation
+#'   \item \code{ping}: Health check
+#' }
+#'
+#' \strong{Tools:}
+#' \itemize{
+#'   \item \code{tools/list}: List available API endpoints
+#'   \item \code{tools/call}: Execute an API endpoint
+#' }
+#'
+#' \strong{Resources:}
+#' \itemize{
+#'   \item \code{resources/list}: List available resources
+#'   \item \code{resources/read}: Read a specific resource
+#'   \item \code{resources/templates/list}: List resource templates
+#' }
+#'
+#' \strong{Prompts:}
+#' \itemize{
+#'   \item \code{prompts/list}: List available prompt templates
+#'   \item \code{prompts/get}: Get a specific prompt with arguments
+#' }
+#'
+#' @section Configuration:
+#'
+#' Customize your MCP server with:
+#' \itemize{
+#'   \item \code{path}: Custom mount path (default: "/mcp")
+#'   \item \code{include_endpoints}: Whitelist specific endpoints
+#'   \item \code{exclude_endpoints}: Blacklist specific endpoints
+#'   \item \code{server_name}: Custom server name
+#'   \item \code{server_version}: Custom server version
+#'   \item \code{debug}: Enable debug logging (stdio only)
+#' }
+#'
+#' @section Learn More:
+#'
+#' \itemize{
+#'   \item MCP Specification: \url{https://modelcontextprotocol.io}
+#'   \item GitHub Repository: \url{https://github.com/armish/plumber2mcp}
+#'   \item Plumber Documentation: \url{https://www.rplumber.io}
+#' }
+#'
+#' @examples
+#' \dontrun{
+#' # Basic HTTP server
+#' library(plumber)
+#' library(plumber2mcp)
+#'
+#' pr <- plumber::pr()
+#' pr$handle("GET", "/echo", function(msg = "hello") {
+#'   list(message = msg)
+#' })
+#'
+#' pr %>%
+#'   pr_mcp(transport = "http") %>%
+#'   pr_run(port = 8000)
+#'
+#' # Full-featured stdio server
+#' pr %>%
+#'   pr_mcp(transport = "stdio") %>%
+#'   pr_mcp_resource(
+#'     uri = "/docs/api",
+#'     func = function() "API Documentation",
+#'     name = "API Docs"
+#'   ) %>%
+#'   pr_mcp_prompt(
+#'     name = "help",
+#'     description = "Get help with the API",
+#'     func = function() "How can I help you use this API?"
+#'   )
+#' }
+#'
+#' @docType package
+#' @name plumber2mcp-package
+NULL