Fix to have agent lambda return descriptive error when request is too long, and UI to display it appropriately so users know they need to shorten their queries

Author: kaleko

src/lambda/agent_request_handler/index.py

@@ -76,26 +76,17 @@ def handler(event, context):
         if not query:
             error_msg = "Query parameter is required"
             logger.error(error_msg)
-            return {
-                "statusCode": 400,
-                "body": error_msg
-            }
+            raise Exception(error_msg)
 
         if len(query) > 5000:
             error_msg = "Query exceeds maximum length of 5000 characters"
             logger.error(f"{error_msg}. Query length: {len(query)}")
-            return {
-                "statusCode": 400,
-                "body": error_msg
-            }
+            raise Exception(error_msg)
 
         if not agent_ids:
             error_msg = "At least one agent ID is required"
             logger.error(error_msg)
-            return {
-                "statusCode": 400,
-                "body": error_msg
-            }
+            raise Exception(error_msg)
 
         # Extract and validate user ID from the identity context
         identity = event.get("identity", {})
@@ -161,7 +152,18 @@ def handler(event, context):
             "body": error_msg
         }
     except Exception as e:
-        error_msg = f"Error processing request: {str(e)}"
+        # Check if this is a validation error that should propagate as GraphQL error
+        error_str = str(e)
+        if any(msg in error_str for msg in [
+            "Query parameter is required",
+            "Query exceeds maximum length",
+            "At least one agent ID is required"
+        ]):
+            # Re-raise validation errors so they become GraphQL errors
+            raise e
+        
+        # Handle other unexpected errors
+        error_msg = f"Error processing request: {error_str}"
         logger.error(error_msg)
         return {
             "statusCode": 500,

src/ui/src/components/document-agents-layout/AgentJobStatus.jsx

@@ -20,6 +20,17 @@ const getStatusIndicator = (status) => {
 };
 
 const AgentJobStatus = ({ jobId, status, error }) => {
+  // Show error even if there's no jobId (for validation errors)
+  if (error && !jobId) {
+    return (
+      <Box padding={{ vertical: 'xs' }}>
+        <div>
+          <strong>Error:</strong> {error}
+        </div>
+      </Box>
+    );
+  }
+
   if (!jobId) {
     return null;
   }

src/ui/src/components/document-agents-layout/DocumentsAgentsLayout.jsx

@@ -199,7 +199,21 @@ const DocumentsAgentsLayout = () => {
       }, 1000);
     } catch (err) {
       logger.error('Error submitting query:', err);
-      const errorMessage = err.errors?.[0]?.message || err.message || 'Failed to submit query';
+      logger.error('Error structure:', JSON.stringify(err, null, 2));
+
+      let errorMessage = 'Failed to submit query';
+
+      // Extract error message from GraphQL error structure
+      if (err.errors && err.errors.length > 0 && err.errors[0].message) {
+        errorMessage = err.errors[0].message;
+      } else if (err.message) {
+        errorMessage = err.message;
+      } else if (err.data && err.data.errors && err.data.errors.length > 0 && err.data.errors[0].message) {
+        errorMessage = err.data.errors[0].message;
+      } else if (typeof err === 'string') {
+        errorMessage = err;
+      }
+
       updateAnalyticsState({
         error: errorMessage,
         jobStatus: 'FAILED',