From 4261adcd5d2b54bbd2c99e18492940c3ef5bc26d Mon Sep 17 00:00:00 2001
From: Dustin Healy <54083382+dustinhealy@users.noreply.github.com>
Date: Thu, 25 Jun 2026 11:09:43 -0700
Subject: [PATCH] fix(mcp): keep app tool calls alive on progress and always
 send tool input

Sets resetTimeoutOnProgress on app-initiated tool calls so a long-running tool
that keeps streaming MCP progress is not aborted at the fixed connection timeout,
matching the model-initiated callTool path.

Always sends the tool-input notification before the result, even when the tool
has no arguments. MCP Apps expect ui tool-input exactly once before the result,
so apps that initialize from ontoolinput no longer stay blank for no-argument
tools.
---
 client/src/hooks/MCP/useAppBridge.ts | 10 +++++-----
 packages/api/src/mcp/MCPManager.ts   |  2 +-
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/client/src/hooks/MCP/useAppBridge.ts b/client/src/hooks/MCP/useAppBridge.ts
index 0ad90f82a8..dfc583c93b 100644
--- a/client/src/hooks/MCP/useAppBridge.ts
+++ b/client/src/hooks/MCP/useAppBridge.ts
@@ -155,11 +155,11 @@ export function useAppBridge(
       bridge.oninitialized = async () => {
         const args = toolArgsRef.current;
         const result = toolResultRef.current;
-        if (args) {
-          await bridge!
-            .sendToolInput({ arguments: args })
-            .catch((err: unknown) => logger.error('[MCP App] sendToolInput failed', err));
-        }
+        // MCP Apps expect tool input exactly once before the result, even for no-argument tools,
+        // so apps that initialize from ontoolinput always receive it.
+        await bridge!
+          .sendToolInput({ arguments: args ?? {} })
+          .catch((err: unknown) => logger.error('[MCP App] sendToolInput failed', err));
         if (result) {
           await bridge!
             .sendToolResult(result as never)
diff --git a/packages/api/src/mcp/MCPManager.ts b/packages/api/src/mcp/MCPManager.ts
index 0f5d95a2f8..91708e9da8 100644
--- a/packages/api/src/mcp/MCPManager.ts
+++ b/packages/api/src/mcp/MCPManager.ts
@@ -966,7 +966,7 @@ Please follow these instructions when using tools from the respective MCP server
         },
       },
       CallToolResultSchema,
-      { timeout: connection.timeout },
+      { timeout: connection.timeout, resetTimeoutOnProgress: true },
     );
 
     return result;