fix: changed truncation length for MCP tools and projects (#8494)

* updated mcp backend to truncate tools name to 30 chars

* updated frontend to truncate tools with 30 chars and truncate project name with 26 chars

* changed it to not exceed 25

* updated one click install to truncate at 26

* updated name

* used constants and helper functions to refactor code

* updated constants

---------

Co-authored-by: Edwin Jose <edwin.jose@datastax.com>

src/backend/base/langflow/api/v1/mcp.py

@@ -19,6 +19,7 @@ from sqlmodel import select
 
 from langflow.api.v1.endpoints import simple_run_flow
 from langflow.api.v1.schemas import SimplifiedAPIRequest
+from langflow.base.mcp.constants import MAX_MCP_TOOL_NAME_LENGTH
 from langflow.base.mcp.util import get_flow_snake_case
 from langflow.helpers.flow import json_schema_from_flow
 from langflow.schema.message import Message
@@ -180,22 +181,35 @@ async def handle_list_tools():
         async with db_service.with_session() as session:
             flows = (await session.exec(select(Flow))).all()
 
+            existing_names = set()
             for flow in flows:
                 if flow.user_id is None:
                     continue
 
-                flow_name = "_".join(flow.name.lower().split())
+                base_name = "_".join(flow.name.lower().split())
+                name = base_name[:MAX_MCP_TOOL_NAME_LENGTH]
+                if name in existing_names:
+                    i = 1
+                    while True:
+                        suffix = f"_{i}"
+                        truncated_base = base_name[: MAX_MCP_TOOL_NAME_LENGTH - len(suffix)]
+                        candidate = f"{truncated_base}{suffix}"
+                        if candidate not in existing_names:
+                            name = candidate
+                            break
+                        i += 1
                 try:
                     tool = types.Tool(
-                        name=flow_name,
+                        name=name,
                         description=f"{flow.id}: {flow.description}"
                         if flow.description
-                        else f"Tool generated from flow: {flow_name}",
+                        else f"Tool generated from flow: {name}",
                         inputSchema=json_schema_from_flow(flow),
                     )
                     tools.append(tool)
+                    existing_names.add(name)
                 except Exception as e:  # noqa: BLE001
-                    msg = f"Error in listing tools: {e!s} from flow: {flow_name}"
+                    msg = f"Error in listing tools: {e!s} from flow: {base_name}"
                     logger.warning(msg)
                     continue
     except Exception as e:

src/backend/base/langflow/api/v1/mcp_projects.py

@@ -30,11 +30,13 @@ from langflow.api.v1.mcp import (
     with_db_session,
 )
 from langflow.api.v1.schemas import MCPInstallRequest, MCPSettings, SimplifiedAPIRequest
-from langflow.base.mcp.util import get_flow_snake_case
+from langflow.base.mcp.constants import MAX_MCP_SERVER_NAME_LENGTH, MAX_MCP_TOOL_NAME_LENGTH
+from langflow.base.mcp.util import get_flow_snake_case, get_unique_name
 from langflow.helpers.flow import json_schema_from_flow
 from langflow.schema.message import Message
 from langflow.services.auth.utils import get_current_active_user
 from langflow.services.database.models import Flow, Folder, User
+from langflow.services.database.models.folder.constants import DEFAULT_FOLDER_NAME, NEW_FOLDER_NAME
 from langflow.services.deps import get_settings_service, get_storage_service, session_scope
 from langflow.services.storage.utils import build_content_type_from_extension
 
@@ -389,9 +391,17 @@ async def install_mcp_config(
             args = ["/c", "uvx", "mcp-proxy", sse_url]
             logger.debug("Windows detected, using cmd command")
 
+        name = project.name
+        name = NEW_FOLDER_NAME if name == DEFAULT_FOLDER_NAME else name
+
         # Create the MCP configuration
         mcp_config = {
-            "mcpServers": {f"lf-{project.name.lower().replace(' ', '_')[:11]}": {"command": command, "args": args}}
+            "mcpServers": {
+                f"lf-{name.lower().replace(' ', '_')[: (MAX_MCP_SERVER_NAME_LENGTH - 4)]}": {
+                    "command": command,
+                    "args": args,
+                }
+            }
         }
 
         # Determine the config file path based on the client and OS
@@ -456,7 +466,7 @@ async def check_installed_mcp_servers(
                 raise HTTPException(status_code=404, detail="Project not found")
 
         # Project server name pattern
-        project_server_name = f"lf-{project.name.lower().replace(' ', '_')[:11]}"
+        project_server_name = f"lf-{project.name.lower().replace(' ', '_')[: (MAX_MCP_SERVER_NAME_LENGTH - 4)]}"
 
         # Check configurations for different clients
         results = []
@@ -517,13 +527,14 @@ class ProjectMCPServer:
                             select(Flow).where(Flow.mcp_enabled == True, Flow.folder_id == self.project_id)  # noqa: E712
                         )
                     ).all()
-
+                    existing_names = set()
                     for flow in flows:
                         if flow.user_id is None:
                             continue
 
                         # Use action_name if available, otherwise construct from flow name
-                        name = flow.action_name or "_".join(flow.name.lower().split())
+                        base_name = flow.action_name or "_".join(flow.name.lower().split())
+                        name = get_unique_name(base_name, MAX_MCP_TOOL_NAME_LENGTH, existing_names)
 
                         # Use action_description if available, otherwise use defaults
                         description = flow.action_description or (
@@ -536,6 +547,7 @@ class ProjectMCPServer:
                             inputSchema=json_schema_from_flow(flow),
                         )
                         tools.append(tool)
+                        existing_names.add(name)
             except Exception as e:  # noqa: BLE001
                 msg = f"Error in listing project tools: {e!s} from flow: {name}"
                 logger.warning(msg)

src/backend/base/langflow/base/mcp/constants.py

@@ -0,0 +1,2 @@
+MAX_MCP_SERVER_NAME_LENGTH = 30
+MAX_MCP_TOOL_NAME_LENGTH = 30

src/backend/base/langflow/base/mcp/util.py

@@ -80,6 +80,20 @@ def create_tool_func(tool_name: str, arg_schema: type[BaseModel], client) -> Cal
     return tool_func
 
 
+def get_unique_name(base_name, max_length, existing_names):
+    name = base_name[:max_length]
+    if name not in existing_names:
+        return name
+    i = 1
+    while True:
+        suffix = f"_{i}"
+        truncated_base = base_name[: max_length - len(suffix)]
+        candidate = f"{truncated_base}{suffix}"
+        if candidate not in existing_names:
+            return candidate
+        i += 1
+
+
 async def get_flow_snake_case(flow_name: str, user_id: str, session, is_action: bool | None = None) -> Flow | None:
     uuid_user_id = UUID(user_id) if isinstance(user_id, str) else user_id
     stmt = select(Flow).where(Flow.user_id == uuid_user_id).where(Flow.is_component == False)  # noqa: E712

src/backend/base/langflow/services/database/models/folder/constants.py

@@ -1,2 +1,3 @@
 DEFAULT_FOLDER_DESCRIPTION = "Manage your own flows. Download and upload projects."
 DEFAULT_FOLDER_NAME = "My Projects"
+NEW_FOLDER_NAME = "Starter Project"

src/frontend/src/constants/constants.ts

@@ -554,6 +554,8 @@ export const USER_PROJECTS_HEADER = "My Collection";
 export const DEFAULT_FOLDER = "Starter Project";
 export const DEFAULT_FOLDER_DEPRECATED = "My Projects";
 
+export const MAX_MCP_SERVER_NAME_LENGTH = 30;
+
 /**
  * Header text for admin page
  * @constant

src/frontend/src/modals/addMcpServerModal/index.tsx

@@ -134,7 +134,7 @@ export default function AddMcpServerModal({
         "snake_case",
         "no_blank",
         "lowercase",
-      ]).slice(0, 20);
+      ]).slice(0, 30);
       try {
         await modifyMCPServer({
           name,
@@ -168,7 +168,7 @@ export default function AddMcpServerModal({
         "snake_case",
         "no_blank",
         "lowercase",
-      ]).slice(0, 20);
+      ]).slice(0, 30);
       try {
         await modifyMCPServer({
           name,
@@ -202,7 +202,7 @@ export default function AddMcpServerModal({
           "snake_case",
           "no_blank",
           "lowercase",
-        ]).slice(0, 20),
+        ]).slice(0, 30),
       }));
     } catch (e: any) {
       setError(e.message || "Invalid input");

src/frontend/src/pages/MainPage/pages/homePage/components/McpServerTab.tsx

@@ -3,6 +3,11 @@ import ShadTooltip from "@/components/common/shadTooltipComponent";
 import ToolsComponent from "@/components/core/parameterRenderComponent/components/ToolsComponent";
 import { Button } from "@/components/ui/button";
 import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs-button";
+import {
+  DEFAULT_FOLDER,
+  DEFAULT_FOLDER_DEPRECATED,
+  MAX_MCP_SERVER_NAME_LENGTH,
+} from "@/constants/constants";
 import { createApiKey } from "@/controllers/API";
 import {
   useGetFlowsMCP,
@@ -183,7 +188,7 @@ const McpServerTab = ({ folderName }: { folderName: string }) => {
 
   const MCP_SERVER_JSON = `{
   "mcpServers": {
-    "lf-${parseString(folderName ?? "project", ["snake_case", "no_blank", "lowercase"]).slice(0, 11)}": {
+    "lf-${parseString(folderName === DEFAULT_FOLDER_DEPRECATED ? DEFAULT_FOLDER : (folderName ?? "project"), ["snake_case", "no_blank", "lowercase"]).slice(0, MAX_MCP_SERVER_NAME_LENGTH - 4)}": {
       "command": "${selectedPlatform === "windows" ? "cmd" : selectedPlatform === "wsl" ? "wsl" : "uvx"}",
       "args": [
         ${

src/frontend/src/utils/mcpUtils.ts

@@ -153,7 +153,7 @@ export function extractMcpServersFromJson(
     throw new Error("No valid MCP server found in the input.");
   }
   return validServers.map(([name, server]) => ({
-    name: name.slice(0, 20),
+    name: name.slice(0, 30),
     command: server.command,
     args: server.args,
     env: server.env && typeof server.env === "object" ? server.env : {},