Add MCP server support with initial list_resources tool

Author: SteveL-MSFT

dsc/Cargo.lock

@@ -19,9 +19,19 @@ crossterm = { version = "0.29" }
 ctrlc = { version = "3.4" }
 dsc_lib = { path = "../dsc_lib" }
 indicatif = { version = "0.18" }
-jsonschema = { version = "0.32", default-features = false }
+jsonschema = { version = "0.33", default-features = false }
 path-absolutize = { version = "3.1" }
 regex = "1.11"
+rmcp = { version = "0.6", features = [
+    "server",
+    "macros",
+    "transport-sse-server",
+    "transport-io",
+    "transport-streamable-http-server",
+    "auth",
+    "elicitation",
+    "schemars",
+] }
 rust-i18n = { version = "3.1" }
 schemars = { version = "1.0" }
 semver = "1.0"
@@ -31,6 +41,8 @@ serde_yaml = { version = "0.9" }
 syntect = { version = "5.0", features = ["default-fancy"], default-features = false }
 sysinfo = { version = "0.37" }
 thiserror = "2.0"
+tokio = "1.47"
+tokio-util = "0.7"
 tracing = { version = "0.1" }
 tracing-subscriber = { version = "0.3", features = ["ansi", "env-filter", "json"] }
 tracing-indicatif = { version = "0.3" }

dsc/Cargo.toml

@@ -35,6 +35,7 @@ resource = "The name of the resource to invoke"
 functionAbout = "Operations on DSC functions"
 listFunctionAbout = "List or find functions"
 version = "The version of the resource to invoke in semver format"
+mcpAbout = "Use DSC as a MCP server"
 
 [main]
 ctrlCReceived = "Ctrl-C received"
@@ -55,6 +56,13 @@ storeMessage = """DSC.exe is a command-line tool and cannot be run directly from
 Visit https://aka.ms/dscv3-docs for more information on how to use DSC.exe.
 
 Press any key to close this window"""
+failedToStartMcpServer = "Failed to start MCP server: %{error}"
+
+[mcp.mod]
+failedToInitialize = "Failed to initialize MCP server: %{error}"
+instructions = "This server provides tools that work with DSC (DesiredStateConfiguration) which enables users to manage and configure their systems declaratively."
+serverStopped = "MCP server stopped"
+failedToWait = "Failed to wait for MCP server: %{error}"
 
 [resolve]
 processingInclude = "Processing Include input"

dsc/locales/en-us.toml

@@ -91,6 +91,8 @@ pub enum SubCommand {
         #[clap(subcommand)]
         subcommand: FunctionSubCommand,
     },
+    #[clap(name = "mcp", about = t!("args.mcpAbout").to_string())]
+    Mcp,
     #[clap(name = "resource", about = t!("args.resourceAbout").to_string())]
     Resource {
         #[clap(subcommand)]

dsc/src/args.rs

@@ -4,6 +4,7 @@
 use args::{Args, SubCommand};
 use clap::{CommandFactory, Parser};
 use clap_complete::generate;
+use mcp::start_mcp_server;
 use rust_i18n::{i18n, t};
 use std::{io, io::Read, process::exit};
 use sysinfo::{Process, RefreshKind, System, get_current_pid, ProcessRefreshKind};
@@ -18,6 +19,7 @@ use crossterm::event;
 use std::env;
 
 pub mod args;
+pub mod mcp;
 pub mod resolve;
 pub mod resource_command;
 pub mod subcommand;
@@ -26,7 +28,8 @@ pub mod util;
 
 i18n!("locales", fallback = "en-us");
 
-fn main() {
+#[tokio::main(flavor = "multi_thread")]
+async fn main() {
     #[cfg(debug_assertions)]
     check_debug();
 
@@ -95,6 +98,13 @@ fn main() {
         SubCommand::Function { subcommand } => {
             subcommand::function(&subcommand);
         },
+        SubCommand::Mcp => {
+            if let Err(err) = start_mcp_server().await {
+                error!("{}", t!("main.failedToStartMcpServer", error = err));
+                exit(util::EXIT_MCP_FAILED);
+            }
+            exit(util::EXIT_SUCCESS);
+        }
         SubCommand::Resource { subcommand } => {
             subcommand::resource(&subcommand, progress_format);
         },

dsc/src/main.rs

@@ -0,0 +1,54 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use crate::mcp::McpServer;
+use dsc_lib::{
+    DscManager,
+    discovery::{
+        command_discovery::ImportedManifest,
+        discovery_trait::DiscoveryKind,
+    },
+    progress::ProgressFormat,
+};
+use rmcp::{ErrorData as McpError, Json, tool, tool_router};
+use schemars::JsonSchema;
+use serde::{Serialize, Deserialize};
+use tokio::task;
+
+#[derive(Serialize, Deserialize, JsonSchema)]
+pub struct ResourceListResult {
+    pub resources: Vec<ImportedManifest>,
+}
+
+#[tool_router]
+impl McpServer {
+    #[must_use]
+    pub fn new() -> Self {
+        Self {
+            tool_router: Self::tool_router()
+        }
+    }
+
+    #[tool(
+        description = "List all DSC resources available on the local machine",
+        annotations(
+            title = "Enumerate all available DSC resources on the local machine",
+            read_only_hint = true,
+            destructive_hint = false,
+            idempotent_hint = true,
+            open_world_hint = true,
+        )
+    )]
+    async fn list_resources(&self) -> Result<Json<ResourceListResult>, McpError> {
+        let result = task::spawn_blocking(move || {
+            let mut dsc = DscManager::new();
+            let mut resources = Vec::new();
+            for resource in dsc.list_available(&DiscoveryKind::Resource, "*", "*", ProgressFormat::None) {
+                resources.push(resource);
+            }
+            ResourceListResult { resources }
+        }).await.map_err(|e| McpError::internal_error(e.to_string(), None))?;
+
+        Ok(Json(result))
+    }
+}

dsc/src/mcp/list_resources.rs

@@ -0,0 +1,70 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+use rmcp::{
+    ErrorData as McpError,
+    handler::server::tool::ToolRouter,
+    model::{InitializeResult, InitializeRequestParam, ServerCapabilities, ServerInfo},
+    service::{RequestContext, RoleServer},
+    ServerHandler,
+    ServiceExt,
+    tool_handler,
+    transport::stdio,
+};
+use rust_i18n::t;
+
+pub mod list_resources;
+
+#[derive(Debug, Clone)]
+pub struct McpServer {
+    tool_router: ToolRouter<Self>
+}
+
+impl Default for McpServer {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+#[tool_handler]
+impl ServerHandler for McpServer {
+    fn get_info(&self) -> ServerInfo {
+        ServerInfo {
+            capabilities: ServerCapabilities::builder()
+                .enable_tools()
+                .build(),
+            instructions: Some(t!("mcp.mod.instructions").to_string()),
+            ..Default::default()
+        }
+    }
+
+    async fn initialize(&self, _request: InitializeRequestParam, _context: RequestContext<RoleServer>) -> Result<InitializeResult, McpError> {
+        Ok(self.get_info())
+    }
+}
+
+/// This function initializes and starts the MCP server, handling any errors that may occur.
+///
+/// # Errors
+///
+/// This function will return an error if the MCP server fails to start.
+pub async fn start_mcp_server() -> Result<(), McpError> {
+    let service = match McpServer::new().serve(stdio()).await {
+        Ok(service) => service,
+        Err(err) => {
+            tracing::error!(error = %err, "Failed to start MCP server");
+            return Err(McpError::internal_error(t!("mcp.mod.failedToInitialize", error = err.to_string()), None));
+        }
+    };
+
+    match service.waiting().await {
+        Ok(_) => {
+            tracing::info!("{}", t!("mcp.mod.serverStopped"));
+        }
+        Err(err) => {
+            tracing::error!("{}", t!("mcp.mod.failedToWait", error = err));
+        }
+    }
+
+    Ok(())
+}

dsc/src/mcp/mod.rs

@@ -744,7 +744,7 @@ fn list_functions(functions: &FunctionDispatcher, function_name: Option<&String>
     }
 }
 
-fn list_resources(dsc: &mut DscManager, resource_name: Option<&String>, adapter_name: Option<&String>, description: Option<&String>, tags: Option<&Vec<String>>, format: Option<&ListOutputFormat>, progress_format: ProgressFormat) {
+pub fn list_resources(dsc: &mut DscManager, resource_name: Option<&String>, adapter_name: Option<&String>, description: Option<&String>, tags: Option<&Vec<String>>, format: Option<&ListOutputFormat>, progress_format: ProgressFormat) {
     let mut write_table = false;
     let mut table = Table::new(&[
         t!("subcommand.tableHeader_type").to_string().as_ref(),

dsc/src/subcommand.rs

@@ -69,6 +69,7 @@ pub const EXIT_VALIDATION_FAILED: i32 = 5;
 pub const EXIT_CTRL_C: i32 = 6;
 pub const EXIT_DSC_RESOURCE_NOT_FOUND: i32 = 7;
 pub const EXIT_DSC_ASSERTION_FAILED: i32 = 8;
+pub const EXIT_MCP_FAILED: i32 = 9;
 
 pub const DSC_CONFIG_ROOT: &str = "DSC_CONFIG_ROOT";
 pub const DSC_TRACE_LEVEL: &str = "DSC_TRACE_LEVEL";