diff --git a/autogpt_platform/backend/backend/api/features/mcp/routes.py b/autogpt_platform/backend/backend/api/features/mcp/routes.py
index 4a190d0cf7..230eb517eb 100644
--- a/autogpt_platform/backend/backend/api/features/mcp/routes.py
+++ b/autogpt_platform/backend/backend/api/features/mcp/routes.py
@@ -120,7 +120,11 @@ async def discover_tools(
                 )
                 for t in tools
             ],
-            server_name=init_result.get("serverInfo", {}).get("name"),
+            server_name=(
+                init_result.get("serverInfo", {}).get("name")
+                or urlparse(request.server_url).hostname
+                or "MCP"
+            ),
             protocol_version=init_result.get("protocolVersion"),
         )
     except HTTPClientError as e:
diff --git a/autogpt_platform/backend/backend/data/graph.py b/autogpt_platform/backend/backend/data/graph.py
index 7f576db8dc..d9edeafe97 100644
--- a/autogpt_platform/backend/backend/data/graph.py
+++ b/autogpt_platform/backend/backend/data/graph.py
@@ -809,6 +809,19 @@ class GraphModel(Graph, GraphMeta):
                         "'credentials' and `*_credentials` are reserved"
                     )
 
+            # Check custom block-level validation (e.g., MCP dynamic tool arguments).
+            # Blocks can override get_missing_input to report additional missing fields
+            # beyond the standard top-level required fields.
+            if for_run:
+                credential_fields = InputSchema.get_credentials_fields()
+                custom_missing = InputSchema.get_missing_input(node.input_default)
+                for field_name in custom_missing:
+                    if (
+                        field_name not in provided_inputs
+                        and field_name not in credential_fields
+                    ):
+                        node_errors[node.id][field_name] = "This field is required"
+
             # Get input schema properties and check dependencies
             input_fields = InputSchema.model_fields
 
diff --git a/autogpt_platform/frontend/src/app/(platform)/build/components/FlowEditor/nodes/CustomNode/components/NodeHeader.tsx b/autogpt_platform/frontend/src/app/(platform)/build/components/FlowEditor/nodes/CustomNode/components/NodeHeader.tsx
index a37cda2159..9a3add62b6 100644
--- a/autogpt_platform/frontend/src/app/(platform)/build/components/FlowEditor/nodes/CustomNode/components/NodeHeader.tsx
+++ b/autogpt_platform/frontend/src/app/(platform)/build/components/FlowEditor/nodes/CustomNode/components/NodeHeader.tsx
@@ -6,7 +6,6 @@ import {
   TooltipProvider,
   TooltipTrigger,
 } from "@/components/atoms/Tooltip/BaseTooltip";
-import { SpecialBlockID } from "@/lib/autogpt-server-api";
 import { beautifyString, cn } from "@/lib/utils";
 import { useState } from "react";
 import { CustomNodeData } from "../CustomNode";
@@ -21,31 +20,8 @@ type Props = {
 
 export const NodeHeader = ({ data, nodeId }: Props) => {
   const updateNodeData = useNodeStore((state) => state.updateNodeData);
-  const isMCPWithTool =
-    data.block_id === SpecialBlockID.MCP_TOOL &&
-    !!data.hardcodedValues?.selected_tool;
 
-  // Derive MCP server label: prefer server_name, fall back to URL hostname.
-  let mcpServerLabel = "MCP";
-  if (isMCPWithTool) {
-    mcpServerLabel =
-      data.hardcodedValues.server_name ||
-      (() => {
-        try {
-          return new URL(data.hardcodedValues.server_url).hostname;
-        } catch {
-          return "MCP";
-        }
-      })();
-  }
-
-  const title =
-    (data.metadata?.customized_name as string) ||
-    (isMCPWithTool
-      ? `${mcpServerLabel}: ${beautifyString(data.hardcodedValues.selected_tool)}`
-      : null) ||
-    data.hardcodedValues?.agent_name ||
-    data.title;
+  const title = (data.metadata?.customized_name as string) || data.title;
 
   const [isEditingTitle, setIsEditingTitle] = useState(false);
   const [editedTitle, setEditedTitle] = useState(title);
diff --git a/autogpt_platform/frontend/src/app/(platform)/build/components/NewControlPanel/NewBlockMenu/Block.tsx b/autogpt_platform/frontend/src/app/(platform)/build/components/NewControlPanel/NewBlockMenu/Block.tsx
index dbcb2d1cb7..4c779380ac 100644
--- a/autogpt_platform/frontend/src/app/(platform)/build/components/NewControlPanel/NewBlockMenu/Block.tsx
+++ b/autogpt_platform/frontend/src/app/(platform)/build/components/NewControlPanel/NewBlockMenu/Block.tsx
@@ -83,14 +83,15 @@ export const Block: BlockComponent = ({
         available_tools: result.availableTools,
         credentials: result.credentials ?? undefined,
       });
-      // Persist the MCP title as customized_name in metadata so it survives
-      // save/load even if server_name is pruned from input_default.
-      if (customNode && result.selectedTool) {
-        const title = `${serverLabel}: ${beautifyString(result.selectedTool)}`;
+      if (customNode) {
+        const title = result.selectedTool
+          ? `${serverLabel}: ${beautifyString(result.selectedTool)}`
+          : undefined;
         updateNodeData(customNode.id, {
           metadata: {
             ...customNode.data.metadata,
-            customized_name: title,
+            credentials_optional: true,
+            ...(title && { customized_name: title }),
           },
         });
       }
@@ -104,7 +105,16 @@ export const Block: BlockComponent = ({
       setMcpDialogOpen(true);
       return;
     }
-    addBlockAndCenter(blockData);
+    const customNode = addBlockAndCenter(blockData);
+    // Set customized_name for agent blocks so the agent's name persists
+    if (customNode && blockData.id === SpecialBlockID.AGENT) {
+      updateNodeData(customNode.id, {
+        metadata: {
+          ...customNode.data.metadata,
+          customized_name: blockData.name,
+        },
+      });
+    }
   };
 
   const handleDragStart = (e: React.DragEvent<HTMLButtonElement>) => {
diff --git a/autogpt_platform/frontend/src/app/(platform)/build/components/legacy-builder/Flow/Flow.tsx b/autogpt_platform/frontend/src/app/(platform)/build/components/legacy-builder/Flow/Flow.tsx
index f566143f40..6cd8721be5 100644
--- a/autogpt_platform/frontend/src/app/(platform)/build/components/legacy-builder/Flow/Flow.tsx
+++ b/autogpt_platform/frontend/src/app/(platform)/build/components/legacy-builder/Flow/Flow.tsx
@@ -42,7 +42,11 @@ import { getV1GetSpecificGraph } from "@/app/api/__generated__/endpoints/graphs/
 import { okData } from "@/app/api/helpers";
 import { IncompatibilityInfo } from "../../../hooks/useSubAgentUpdate/types";
 import { Key, storage } from "@/services/storage/local-storage";
-import { findNewlyAddedBlockCoordinates, getTypeColor } from "@/lib/utils";
+import {
+  beautifyString,
+  findNewlyAddedBlockCoordinates,
+  getTypeColor,
+} from "@/lib/utils";
 import { history } from "../history";
 import { CustomEdge } from "../CustomEdge/CustomEdge";
 import ConnectionLine from "../ConnectionLine";
@@ -748,9 +752,26 @@ const FlowEditor: React.FC<{
           block_id: blockID,
           isOutputStatic: nodeSchema.staticOutput,
           uiType: nodeSchema.uiType,
-          // MCP blocks have optional credentials (public servers don't need auth)
+          // Set customized_name at creation so it persists through save/load
           ...(blockID === SpecialBlockID.MCP_TOOL && {
-            metadata: { credentials_optional: true },
+            metadata: {
+              credentials_optional: true,
+              ...(finalHardcodedValues.selected_tool && {
+                customized_name: `${
+                  finalHardcodedValues.server_name ||
+                  (() => {
+                    try {
+                      return new URL(finalHardcodedValues.server_url).hostname;
+                    } catch {
+                      return "MCP";
+                    }
+                  })()
+                }: ${beautifyString(finalHardcodedValues.selected_tool)}`,
+              }),
+            },
+          }),
+          ...(blockID === SpecialBlockID.AGENT && {
+            metadata: { customized_name: blockName },
           }),
         },
       };
@@ -881,8 +902,6 @@ const FlowEditor: React.FC<{
 
       return (
         node.data.metadata?.customized_name ||
-        (node.data.uiType == BlockUIType.AGENT &&
-          node.data.hardcodedValues.agent_name) ||
         node.data.blockType.replace(/Block$/, "")
       );
     },