HTTP requests hang indefinitely due to IDA main thread synchronization deadlock

Summary

MCP tool calls hang forever when IDA's main thread is blocked by a dialog, auto-analysis, or other blocking operation. The HTTP server becomes unresponsive and never returns a response to the client.

Observed Behavior

1. First few MCP requests complete successfully
2. At some point, a request hangs indefinitely
3. All subsequent requests also hang
4. The process must be forcefully terminated

Call Stack When Hung

ntdll.dll!00007ffffd581e54()
mswsock.dll!00007ffff98368ea()
mswsock.dll!00007ffff98365c4()
ws2_32.dll!00007ffffb569781()
select.pyd!00007fff9548243b()
select.pyd!00007fff9548224f()
python311.dll!00007ffe152ab98e()
python311.dll!00007ffe152a2264()
python311.dll!00007ffe152c6c97()
...

Root Cause Analysis

The @idaread and @idawrite decorators in ida_mcp/sync.py use idaapi.execute_sync() to marshal calls to IDA's main thread. The worker thread then blocks indefinitely waiting for the result:

# ida_mcp/sync.py, line 66-70
idaapi.execute_sync(runned, safety_mode)
res = res_container.get()  # Blocks forever if main thread never executes runned()

Deadlock sequence:

HTTP Worker Thread                    IDA Main Thread
─────────────────                    ───────────────
1. Receive HTTP request
2. Call @idaread decorated function
3. execute_sync() queues task
4. Block on res_container.get()
        │                            Main thread is blocked by:
        │                            - Modal dialog (Open/Save/etc.)
        │                            - Auto-analysis in progress
        │                            - Debugger breakpoint
        │                            - IDAPython script running
        ▼
   Waiting forever...                Task never gets executed

Steps to Reproduce

1. Start IDA Pro and load a binary
2. Enable the MCP plugin (Edit -> Plugins -> MCP or Ctrl+Alt+M)
3. Connect an MCP client (e.g., Claude Desktop)
4. Make a few successful tool calls
5. While a request is pending, trigger any of these in IDA:
   • Open File -> Open dialog
   • Start analyzing a new binary segment
   • Hit a breakpoint while debugging
6. Result: The pending request hangs forever, server becomes unresponsive

Environment

• OS: Windows 10/11
• Python: 3.11
• IDA Pro: 8.x / 9.x
• MCP Client: Claude Desktop / Cursor / Other