Preflight Checklist
What's Wrong?
Bug Report — Claude Desktop (Windows): MCP tool calls hard-terminated at ~4 minutes, and bridge wedge after repeated timeouts
Summary
On Claude Desktop for Windows, any MCP tool call whose execution exceeds ~4 minutes (~240 s)
is terminated client-side with:
"No result received from the Claude Desktop app after waiting 4 minutes. The local MCP
server providing this tool may be unresponsive, crashed, or not running."
The MCP server is healthy and still processing; it returns normally when the same call
finishes faster. The displayed message is misleading (it blames the server, which is fine).
A more severe secondary effect: after a few such timeouts the bridge wedges across ALL
connected MCP servers (see below).
Environment
- Claude Desktop: 1.11187.1 (MSIX package Claude_1.11187.1.0_x64__pzs8sxrjxfjjc)
- OS: Windows 11 Pro, build 10.0.26200
- MCP server(s): local stdio servers (custom), C# MCP SDK 1.3, launched by Claude Desktop
- Transport: local stdio
Severity / Impact
Medium–High for infrastructure/automation use. Blocks any MCP tool whose single call runs
~4 min (DISM /Online /Cleanup-Image /ScanHealth, sfc, long SQL queries, backups, large
file ops, long scripts). The secondary wedge requires restarting MCP servers / the app.
Expected behavior
Long calls run to completion, OR the client honors a configurable/request-level timeout. A
single timed-out call must never wedge other healthy MCP servers. MCP supports long-running
operations and progress notifications; a fixed client cap should not silently kill them.
Actual behavior
~240 s cap on every tool call, ignoring any server-side timeout; misleading error text;
cross-server wedge after repeated timeouts.
Evidence / Diagnosis — it is the client/bridge, not the server
- Multiple runs of Start-Sleep 280 all terminated at ~4 min.
- The tool exposes a server-side timeout_seconds parameter; setting it to 600 does NOT change
the outcome -> the cap is in the Claude Desktop MCP client, not the server.
- A trivial call immediately after a single terminated long call returned in <200 ms (server
healthy); but after further timeouts, trivial calls on ALL connected servers also hung 4 min.
Tested across versions
Reproduced consistently across multiple Claude Desktop updates, including 1.11187.2 (latest
as of testing).
Requested fix (any of)
- Make the MCP tool-call timeout configurable (per-server and/or global).
- Honor MCP progress notifications to reset/extend the timeout.
- Raise/remove the fixed cap for local stdio servers.
- Isolate per-server connections so one timed-out call cannot wedge other MCP servers.
- Fix the misleading error text (server is healthy, not crashed).
What Should Happen?
To work normally with MCP tools
Error Messages/Logs
Tool result could not be submitted. The request may have expired or the connection was interrupted. Refresh the page to continue.
Steps to Reproduce
Steps to reproduce — primary (4-min cap)
- Connect any local stdio MCP server exposing a long-running tool.
- Invoke a call that takes > ~4 minutes, e.g.:
Start-Sleep -Seconds 280 # 4m40s
- The call is terminated at ~4 minutes; the result is never returned.
Steps to reproduce — secondary (bridge wedge)
- Trigger the 4-min timeout above 2–3 times (and/or a long-timed-out call on a second MCP server).
- Issue a TRIVIAL call afterwards (1-line command, server timeout 30 s).
- Observed: after the first one or two timeouts a trivial call may still recover (<200 ms),
but after repeated timeouts every connected MCP server becomes unresponsive — trivial calls
then also time out at the same 4-minute mark — until the user restarts the MCP servers /
Claude Desktop. Points to a shared client-side bridge resource (connection/worker pool or
event loop) being exhausted/blocked by the capped-but-still-running requests.
Claude Model
Opus
Is this a regression?
I don't know
Last Working Version
No response
Claude Code Version
Claude 1.11187.2 (8cc3af) 2026-06-05T04:43:40.000Z
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
Windows Terminal
Additional Information
mcp_log.zip
Claude-MCP-4min-evidence.zip
Preflight Checklist
What's Wrong?
Bug Report — Claude Desktop (Windows): MCP tool calls hard-terminated at ~4 minutes, and bridge wedge after repeated timeouts
Summary
On Claude Desktop for Windows, any MCP tool call whose execution exceeds ~4 minutes (~240 s)
is terminated client-side with:
"No result received from the Claude Desktop app after waiting 4 minutes. The local MCP
server providing this tool may be unresponsive, crashed, or not running."
The MCP server is healthy and still processing; it returns normally when the same call
finishes faster. The displayed message is misleading (it blames the server, which is fine).
A more severe secondary effect: after a few such timeouts the bridge wedges across ALL
connected MCP servers (see below).
Environment
Severity / Impact
Medium–High for infrastructure/automation use. Blocks any MCP tool whose single call runs
Expected behavior
Long calls run to completion, OR the client honors a configurable/request-level timeout. A
single timed-out call must never wedge other healthy MCP servers. MCP supports long-running
operations and progress notifications; a fixed client cap should not silently kill them.
Actual behavior
~240 s cap on every tool call, ignoring any server-side timeout; misleading error text;
cross-server wedge after repeated timeouts.
Evidence / Diagnosis — it is the client/bridge, not the server
the outcome -> the cap is in the Claude Desktop MCP client, not the server.
healthy); but after further timeouts, trivial calls on ALL connected servers also hung 4 min.
Tested across versions
Reproduced consistently across multiple Claude Desktop updates, including 1.11187.2 (latest
as of testing).
Requested fix (any of)
What Should Happen?
To work normally with MCP tools
Error Messages/Logs
Steps to Reproduce
Steps to reproduce — primary (4-min cap)
Start-Sleep -Seconds 280 # 4m40s
Steps to reproduce — secondary (bridge wedge)
but after repeated timeouts every connected MCP server becomes unresponsive — trivial calls
then also time out at the same 4-minute mark — until the user restarts the MCP servers /
Claude Desktop. Points to a shared client-side bridge resource (connection/worker pool or
event loop) being exhausted/blocked by the capped-but-still-running requests.
Claude Model
Opus
Is this a regression?
I don't know
Last Working Version
No response
Claude Code Version
Claude 1.11187.2 (8cc3af) 2026-06-05T04:43:40.000Z
Platform
Anthropic API
Operating System
Windows
Terminal/Shell
Windows Terminal
Additional Information
mcp_log.zip
Claude-MCP-4min-evidence.zip