From b9ac69f79adbdc4b393371fc9997535d5dba670d Mon Sep 17 00:00:00 2001
From: Guoyu Su <yss2813483011xxl@gmail.com>
Date: Wed, 15 Jul 2026 19:33:31 +0800
Subject: [PATCH] fix(mcp): require managed runtime

---
 src-tauri/src/commands/ai.rs  |  5 +++--
 src-tauri/src/commands/mcp.rs | 30 ++++++++++++++++++++++++++----
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src-tauri/src/commands/ai.rs b/src-tauri/src/commands/ai.rs
index b7beb31a9..8c4fd2318 100644
--- a/src-tauri/src/commands/ai.rs
+++ b/src-tauri/src/commands/ai.rs
@@ -89,16 +89,17 @@ pub async fn ai_agent_stream(
     allow_write_sql: Option<bool>,
 ) -> Result<String, String> {
     let request = resolve_codex_cli_request(request);
-    let cancelled = dbx_core::ai::register_stream(&session_id).await;
 
     let parsed_db_type: DatabaseType =
         serde_json::from_str(&format!("\"{}\"", db_type)).map_err(|_| format!("Unknown database type: {db_type}"))?;
 
     let cli_mcp_server_command = if matches!(request.config.provider, AiProvider::CodexCli) {
-        super::mcp::resolve_mcp_server_command().await.map(|(program, args)| CliAgentCommandSpec { program, args })
+        let (program, args) = super::mcp::resolve_mcp_server_command().await?;
+        Some(CliAgentCommandSpec { program, args })
     } else {
         None
     };
+    let cancelled = dbx_core::ai::register_stream(&session_id).await;
     let production_database = state
         .configs
         .read()
diff --git a/src-tauri/src/commands/mcp.rs b/src-tauri/src/commands/mcp.rs
index 306476719..d4744779a 100644
--- a/src-tauri/src/commands/mcp.rs
+++ b/src-tauri/src/commands/mcp.rs
@@ -201,8 +201,11 @@ async fn fetch_latest_mcp_version() -> Result<String, String> {
     Ok(package.version)
 }
 
-pub(crate) async fn resolve_mcp_server_command() -> Option<(String, Vec<String>)> {
-    tauri::async_runtime::spawn_blocking(resolve_mcp_server_command_sync).await.ok().flatten()
+pub(crate) async fn resolve_mcp_server_command() -> Result<(String, Vec<String>), String> {
+    let command = tauri::async_runtime::spawn_blocking(resolve_mcp_server_command_sync)
+        .await
+        .map_err(|err| format!("Failed to resolve DBX MCP Server runtime: {err}"))?;
+    require_managed_mcp_command(command)
 }
 
 fn resolve_mcp_server_command_sync() -> Option<(String, Vec<String>)> {
@@ -225,6 +228,15 @@ fn resolve_managed_mcp_command(
     None
 }
 
+fn require_managed_mcp_command(command: Option<(String, Vec<String>)>) -> Result<(String, Vec<String>), String> {
+    command.ok_or_else(|| {
+        format!(
+            "DBX MCP Server is unavailable: no compatible Node.js ({}) installation containing {} was found. Install MCP Server from DBX settings and try again.",
+            MCP_MIN_NODE_VERSION_REQUIREMENT, MCP_PACKAGE_NAME
+        )
+    })
+}
+
 fn resolve_node_runtime() -> Option<NodeRuntime> {
     let mut seen = HashSet::new();
     let mut fallback = None;
@@ -799,8 +811,9 @@ mod tests {
     use super::{bash_login_script, canonical_runtime_path, NodeRuntimeCandidate};
     use super::{
         is_mcp_compatible_node_version, mcp_command_for_runtime, normalized_reported_path, npm_cli_candidates,
-        parse_node_version, prefer_runtime, prefixed_output_path, resolve_managed_mcp_command,
-        stdout_after_shell_marker, NodeRuntime, NodeVersion, SHELL_COMMAND_MARKER,
+        parse_node_version, prefer_runtime, prefixed_output_path, require_managed_mcp_command,
+        resolve_managed_mcp_command, stdout_after_shell_marker, NodeRuntime, NodeVersion,
+        MCP_MIN_NODE_VERSION_REQUIREMENT, MCP_PACKAGE_NAME, SHELL_COMMAND_MARKER,
     };
     #[cfg(not(windows))]
     use super::{shell_command_script, shell_quote};
@@ -944,6 +957,15 @@ mod tests {
         assert!(command.is_none());
     }
 
+    #[test]
+    fn desktop_launch_requires_a_managed_mcp_command() {
+        let error = require_managed_mcp_command(None).unwrap_err();
+
+        assert!(error.contains(MCP_MIN_NODE_VERSION_REQUIREMENT));
+        assert!(error.contains(MCP_PACKAGE_NAME));
+        assert!(error.contains("DBX settings"));
+    }
+
     #[test]
     fn npm_cli_candidates_stay_with_the_selected_node_installation() {
         let candidates = npm_cli_candidates(PathBuf::from("/runtime/node-24/bin/node").as_path());