fix(mcp-memory,server): prevent lock contention and executor blocking in TasksTool::List

server/src/handlers/tasks.rs

@@ -256,10 +256,10 @@ impl McpTool for TasksHandler {
                 }
             }
             TasksTool::List { git_branch, status, summary_level, max_tokens, offset } => {
-                let level = summary_level.as_deref().unwrap_or("detailed");
+                let level = summary_level.clone().unwrap_or_else(|| "detailed".to_string());
                 let offset = offset.unwrap_or(0);
-                let data = state.project.tasks.read_with(|tasks| {
-                    let matching: Vec<_> = tasks
+                let filtered: Vec<serde_json::Value> = state.project.tasks.read_with(|tasks| {
+                    tasks
                         .iter()
                         .filter(|t| {
                             let status_match = match status.as_deref() {
@@ -273,17 +273,17 @@ impl McpTool for TasksHandler {
                             };
                             status_match && branch_match
                         })
-                        .collect();
-
-                    let mut filtered: Vec<_> = matching
-                        .into_iter()
                         .skip(offset)
-                        .map(|t| match level {
+                        .map(|t| match level.as_str() {
                             "compact" => serde_json::json!({ "id": t.id, "title": t.title, "status": t.status }),
                             "full" => serde_json::to_value(t).unwrap_or_default(),
                             _ => serde_json::json!({ "id": t.id, "title": t.title, "status": t.status, "description": t.description, "git_branch": t.git_branch }),
                         })
-                        .collect();
+                        .collect()
+                });
+
+                let data = tokio::task::spawn_blocking(move || {
+                    let mut filtered = filtered;
                     let mut json_str = serde_yaml::to_string(&filtered)?;
                     if let Some(max_t) = max_tokens {
                         let char_limit = max_t * 4;
@@ -293,7 +293,8 @@ impl McpTool for TasksHandler {
                         }
                     }
                     Ok::<String, crate::error::AppError>(json_str)
-                })?;
+                }).await.map_err(|e| crate::error::AppError::Internal(format!("Task serialization thread panicked: {}", e)))??;
+
                 Ok(data)
             }
             TasksTool::SetCriteria { id, criteria: criteria_list } => {