feat(handlers): enrich semantic error messages with prescriptive tool hints to prevent LLM hallucination traps

server/src/handlers/tasks.rs

@@ -113,7 +113,7 @@ impl McpTool for DeleteTaskHandler {
             ][0]
             .clone())
         } else {
-            Err("Task not found.".to_string())
+            Err("Task not found. Please use the list_active_tasks tool to verify the correct task ID.".to_string())
         }
     }
 }
@@ -256,7 +256,7 @@ impl McpTool for UpdateTaskStatusHandler {
         } else if found {
             Ok("Task status updated.".to_string())
         } else {
-            Err("Task not found.".to_string())
+            Err("Task not found. Please use the list_active_tasks tool to verify the correct task ID.".to_string())
         }
     }
 }
@@ -336,7 +336,7 @@ impl McpTool for SetAcceptanceCriteriaHandler {
         if success {
             Ok("Acceptance criteria set successfully.".to_string())
         } else {
-            Err("Task not found.".to_string())
+            Err("Task not found. Please use the list_active_tasks tool to verify the correct task ID.".to_string())
         }
     }
 }
@@ -444,7 +444,7 @@ impl McpTool for UpdateMilestoneHandler {
         if found {
             Ok("Milestone updated".to_string())
         } else {
-            Err("Milestone not found".to_string())
+            Err("Milestone not found. Please verify the milestone ID using list_milestones.".to_string())
         }
     }
 }