Update MCP to make it actually work

- Add Streamable HTTP support to be compatible with latest (2025-11-xx) MCP standards.
- Move some tools that are really resources to resources.
- Fix broken tools
- It now works with Claude Code and MCP inspector, but not with Antigravity, nor Amp.

Author: vdavid

.claude/settings.json

@@ -0,0 +1,7 @@
+{
+  "mcpServers": {
+    "cmdr": {
+      "url": "http://localhost:9224/mcp"
+    }
+  }
+}

apps/desktop/src-tauri/Cargo.lock

@@ -47,6 +47,7 @@ reqwest = { version = "0.12", features = ["json", "rustls-tls"], default-feature
 # MCP server
 axum = "0.8"
 tokio = { version = "1", features = ["rt-multi-thread", "net", "time", "sync", "macros"] }
+futures-util = "0.3"
 tower-http = { version = "0.6", features = ["cors"] }
 [target.'cfg(not(any(target_os = "android", target_os = "ios")))'.dependencies]
 tauri-plugin-window-state = "2"
@@ -62,6 +63,7 @@ objc2-foundation = { version = "0.3", features = [
     "NSURL", "NSString", "NSDictionary", "NSDate", "NSArray", "NSValue", "NSError",
     "NSFileManager", "NSNetServices", "NSRunLoop"
 ] }
+objc2-app-kit = { version = "0.3", features = ["NSApplication", "NSRunningApplication"] }
 smb = "0.11.1"
 smb-rpc = "=0.11.1"
 chrono = "0.4"

apps/desktop/src-tauri/Cargo.toml

@@ -8,7 +8,9 @@ use tauri::{AppHandle, Emitter, Manager, Runtime};
 
 use super::pane_state::PaneStateStore;
 use super::protocol::{INTERNAL_ERROR, INVALID_PARAMS};
-use crate::commands::ui::{set_view_mode, toggle_hidden_files};
+use crate::commands::ui::{
+    copy_to_clipboard, get_info, quick_look, set_view_mode, show_in_finder, toggle_hidden_files,
+};
 
 /// Result of tool execution.
 pub type ToolResult = Result<Value, ToolError>;
@@ -63,13 +65,20 @@ pub fn execute_tool<R: Runtime>(app: &AppHandle<R>, name: &str, params: &Value)
 fn execute_app_command<R: Runtime>(app: &AppHandle<R>, name: &str) -> ToolResult {
     match name {
         "app_quit" => {
-            app.emit("mcp-action", json!({"action": "quit"}))
-                .map_err(|e| ToolError::internal(e.to_string()))?;
+            app.exit(0);
             Ok(json!({"success": true}))
         }
         "app_hide" => {
-            app.emit("mcp-action", json!({"action": "hide"}))
-                .map_err(|e| ToolError::internal(e.to_string()))?;
+            // Use macOS NSApplication hide (same as ⌘H)
+            #[cfg(target_os = "macos")]
+            {
+                use objc2::MainThreadMarker;
+                use objc2_app_kit::NSApplication;
+                if let Some(mtm) = MainThreadMarker::new() {
+                    let app_instance = NSApplication::sharedApplication(mtm);
+                    app_instance.hide(None);
+                }
+            }
             Ok(json!({"success": true}))
         }
         "app_about" => {
@@ -108,16 +117,6 @@ fn execute_pane_command<R: Runtime>(app: &AppHandle<R>, name: &str) -> ToolResul
                 .map_err(|e| ToolError::internal(e.to_string()))?;
             Ok(json!({"success": true}))
         }
-        "pane_leftVolumeChooser" => {
-            app.emit("mcp-action", json!({"action": "leftVolumeChooser"}))
-                .map_err(|e| ToolError::internal(e.to_string()))?;
-            Ok(json!({"success": true}))
-        }
-        "pane_rightVolumeChooser" => {
-            app.emit("mcp-action", json!({"action": "rightVolumeChooser"}))
-                .map_err(|e| ToolError::internal(e.to_string()))?;
-            Ok(json!({"success": true}))
-        }
         _ => Err(ToolError::invalid_params(format!("Unknown pane command: {name}"))),
     }
 }
@@ -166,31 +165,54 @@ fn execute_sort_command<R: Runtime>(app: &AppHandle<R>, name: &str) -> ToolResul
 }
 
 /// Execute a file command.
+/// Gets the selected file from PaneStateStore and operates on it directly.
 fn execute_file_command<R: Runtime>(app: &AppHandle<R>, name: &str) -> ToolResult {
-    let action = match name {
-        "file_showInFinder" => "showInFinder",
-        "file_copyPath" => "copyPath",
-        "file_copyFilename" => "copyFilename",
-        "file_quickLook" => "quickLook",
-        "file_getInfo" => "getInfo",
-        _ => return Err(ToolError::invalid_params(format!("Unknown file command: {name}"))),
+    // Get the selected file from pane state
+    let store = app
+        .try_state::<PaneStateStore>()
+        .ok_or_else(|| ToolError::internal("Pane state not initialized"))?;
+
+    let focused = store.get_focused_pane();
+    let pane = if focused == "right" {
+        store.get_right()
+    } else {
+        store.get_left()
     };
 
-    app.emit("mcp-action", json!({"action": action, "type": "file"}))
-        .map_err(|e| ToolError::internal(e.to_string()))?;
-    Ok(json!({"success": true}))
+    let selected = pane
+        .files
+        .get(pane.selected_index)
+        .ok_or_else(|| ToolError::internal("No file selected"))?;
+
+    match name {
+        "file_showInFinder" => {
+            show_in_finder(selected.path.clone()).map_err(ToolError::internal)?;
+            Ok(json!({"success": true, "path": selected.path}))
+        }
+        "file_copyPath" => {
+            copy_to_clipboard(app.clone(), selected.path.clone()).map_err(ToolError::internal)?;
+            Ok(json!({"success": true, "copied": selected.path}))
+        }
+        "file_copyFilename" => {
+            copy_to_clipboard(app.clone(), selected.name.clone()).map_err(ToolError::internal)?;
+            Ok(json!({"success": true, "copied": selected.name}))
+        }
+        "file_quickLook" => {
+            quick_look(selected.path.clone()).map_err(ToolError::internal)?;
+            Ok(json!({"success": true, "path": selected.path}))
+        }
+        "file_getInfo" => {
+            get_info(selected.path.clone()).map_err(ToolError::internal)?;
+            Ok(json!({"success": true, "path": selected.path}))
+        }
+        _ => Err(ToolError::invalid_params(format!("Unknown file command: {name}"))),
+    }
 }
 
 /// Execute a volume command.
+/// Note: volume listing is now a resource (cmdr://volumes), not a tool.
 fn execute_volume_command<R: Runtime>(app: &AppHandle<R>, name: &str, params: &Value) -> ToolResult {
     match name {
-        "volume_list" => {
-            // Request volume list from frontend - it will respond via event
-            app.emit("mcp-volume-list-request", ())
-                .map_err(|e| ToolError::internal(e.to_string()))?;
-            // For now, return a placeholder - real implementation needs async response
-            Ok(json!({"note": "Volume list requested, check mcp-volume-list-response event"}))
-        }
         "volume_selectLeft" | "volume_selectRight" => {
             let index = params
                 .get("index")

apps/desktop/src-tauri/src/mcp/executor.rs

@@ -1,12 +1,13 @@
 //! MCP (Model Context Protocol) server module.
 //!
-//! Provides an HTTP+SSE server that exposes cmdr functionality as MCP tools,
+//! Provides a Streamable HTTP server that exposes cmdr functionality as MCP tools,
 //! enabling AI agents to control the file manager.
 
 mod config;
 mod executor;
 pub mod pane_state;
 mod protocol;
+mod resources;
 mod server;
 mod tools;
 

apps/desktop/src-tauri/src/mcp/mod.rs

@@ -1,4 +1,7 @@
-//! MCP protocol message types and handling.
+//! MCP protocol message types and handling (spec version 2025-11-25).
+//!
+//! Implements JSON-RPC 2.0 message format as required by MCP.
+//! See: https://modelcontextprotocol.io/specification/2025-11-25
 
 use serde::{Deserialize, Serialize};
 use serde_json::Value;
@@ -35,11 +38,9 @@ pub struct McpError {
     pub data: Option<Value>,
 }
 
-// MCP error codes (JSON-RPC standard + MCP specific)
-// Some are reserved for future use
+// JSON-RPC 2.0 standard error codes
 #[allow(dead_code)]
 pub const PARSE_ERROR: i32 = -32700;
-#[allow(dead_code)]
 pub const INVALID_REQUEST: i32 = -32600;
 pub const METHOD_NOT_FOUND: i32 = -32601;
 pub const INVALID_PARAMS: i32 = -32602;
@@ -98,6 +99,7 @@ pub struct ServerCapabilities {
 #[derive(Debug, Clone, Serialize)]
 pub struct Capabilities {
     pub tools: ToolCapabilities,
+    pub resources: ResourceCapabilities,
 }
 
 #[derive(Debug, Clone, Serialize)]
@@ -106,6 +108,13 @@ pub struct ToolCapabilities {
     pub list_changed: bool,
 }
 
+#[derive(Debug, Clone, Serialize)]
+pub struct ResourceCapabilities {
+    #[serde(rename = "listChanged")]
+    pub list_changed: bool,
+    pub subscribe: bool,
+}
+
 #[derive(Debug, Clone, Serialize)]
 pub struct ServerInfo {
     pub name: String,
@@ -118,6 +127,10 @@ impl Default for ServerCapabilities {
             protocol_version: "2024-11-05".to_string(),
             capabilities: Capabilities {
                 tools: ToolCapabilities { list_changed: false },
+                resources: ResourceCapabilities {
+                    list_changed: false,
+                    subscribe: false,
+                },
             },
             server_info: ServerInfo {
                 name: "cmdr".to_string(),
@@ -188,4 +201,17 @@ mod tests {
         assert_eq!(caps.server_info.name, "cmdr");
         assert!(!caps.capabilities.tools.list_changed);
     }
+
+    #[test]
+    fn test_error_with_data() {
+        let response = McpResponse::error_with_data(
+            Some(json!(1)),
+            INVALID_PARAMS,
+            "Invalid params",
+            json!({"details": "missing field"}),
+        );
+        let json = serde_json::to_value(&response).unwrap();
+
+        assert_eq!(json["error"]["data"]["details"], "missing field");
+    }
 }