Error using mcpcoreserver.internal.fs.DefaultFSAdaptor/ensureSecureFolder (line 27) Insecure permissions

[allmo-bfcs]

Bug Report

Hello,

I installed the agentic toolkit as documented.
When I ran satk_initialize I got the following error:

satk_initialize
Warning: shareMATLABSession failed: Insecure permissions on 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB
MCP Core Server': Access must be restricted to the user only.
The MCP server may not be able to connect to this MATLAB session.
MATLAB-side MCP components may not be installed. Run:
C:\Users\moritz.allmendinger.matlab\agentic-toolkits\bin\matlab-mcp-core-server.exe --setup-matlab
--matlab-root="C:\Program Files\MATLAB\R2025b"
Then restart MATLAB and re-run satk_initialize.
In satk_initialize
In [mcpcoreserver.internal.fs/DefaultFSAdaptor/ensureSecureFolder](matlab:matlab.lang.internal.introspective.errorDocCallback('mcpcoreserver.internal.fs/DefaultFSAdaptor/ensureSecureFolder', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal+fs\DefaultFSAdaptor.m', 26)) ([line 26](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal+fs\DefaultFSAdaptor.m',26,0)))
In [mcpcoreserver.internal.shareMATLABSession](matlab:matlab.lang.internal.introspective.errorDocCallback('mcpcoreserver.internal.shareMATLABSession', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal\shareMATLABSession.m', 19)) ([line 19](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal\shareMATLABSession.m',19,0)))
In [shareMATLABSession](matlab:matlab.lang.internal.introspective.errorDocCallback('shareMATLABSession', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox\shareMATLABSession.m', 8)) ([line 8](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox\shareMATLABSession.m',8,0)))

Simulink Agentic Toolkit - Installation Check

Prerequisites
✓ MATLAB 25.2.0.3177638 (R2025b) Update 5
✓ Simulink installed and licensed

MATLAB Environment
✓ All 7 tool entry points on path
✓ Package resolution correct (+sage, +mbd inside SATK)

MCP Server
✓ matlab-mcp-core-server.exe found: C:\Users\moritz.allmendinger.matlab\agentic-toolkits\bin\matlab-mcp-core-server.exe

MCP Connectivity
✓ shareMATLABSession available (MATLAB-side MCP components installed)
✓ MATLAB connector running (port 31519)

===============================================
Result: PASS

K>> shareMATLABSession
Error using [mcpcoreserver.internal.fs.DefaultFSAdaptor/ensureSecureFolder](matlab:matlab.lang.internal.introspective.errorDocCallback('mcpcoreserver.internal.fs.DefaultFSAdaptor/ensureSecureFolder', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal+fs\DefaultFSAdaptor.m', 27)) ([line 27](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal+fs\DefaultFSAdaptor.m',27,0)))
Insecure permissions on 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB MCP Core Server': Access must be
restricted to the user only.

Error in [mcpcoreserver.internal.shareMATLABSession](matlab:matlab.lang.internal.introspective.errorDocCallback('mcpcoreserver.internal.shareMATLABSession', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal\shareMATLABSession.m', 19)) ([line 19](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox+mcpcoreserver+internal\shareMATLABSession.m',19,0)))
options.FSAdaptor.ensureSecureFolder(appDataFolder);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in [shareMATLABSession](matlab:matlab.lang.internal.introspective.errorDocCallback('shareMATLABSession', 'C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox\shareMATLABSession.m', 8)) ([line 8](matlab: opentoline('C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB Add-Ons\Toolboxes\MATLAB MCP Core Server Toolbox\shareMATLABSession.m',8,0)))
mcpcoreserver.internal.shareMATLABSession();
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In my opinion, this is mainly due to the shareMATLABSession function.

Regards,
Moritz

Additional Context

No response

[derrick-mw]

Hey @allmo-bfcs ,

I've transferred this issue to the MATLAB MCP repo as this is an MCP issue.

Thanks,
Derrick

[ybenouag]

Hi @allmo-bfcs,

Thanks for the report! Looks like the existing %APPDATA%\MathWorks\MATLAB MCP Core Server folder has Windows ACLs we don't recognize, so the security check rejects it.

Could you try this?

1. Close MATLAB.
2. Delete C:\Users\moritz.allmendinger\AppData\Roaming\MathWorks\MATLAB MCP Core Server (File Explorer is fine, or rmdir /s /q "%APPDATA%\MathWorks\MATLAB MCP Core Server" from cmd.exe).
3. Re-launch MATLAB and run satk_initialize again.

If that doesn't help, could you share the toolbox version?

ver("MATLAB MCP Core Server Toolbox")

Thanks,
Yannis

[allmo-bfcs]

Hello @ybenouag,

yes, it was a Windows ACL topic.
Sometimes MATLAB and VS Code are launched with different user contexts and permissions on my pc.
I reinstalled the Toolbox with the same permissions for both programs.
After that, satk_initialize no longer returned any errors.

Regards,
Moritz