ValidationError on startup

[NicolasB-Pro]

Hello ! Sounds like there is an issue somewhere but I can't find that log setting anywhere.

Describe the bug

When I start the extension I have this message :

pgsql: PostgreSQL Tools Service terminated unexpectedly.

Related to this log :

Traceback (most recent call last):
File "ossdbtoolsservice_main.py", line 16, in
File "", line 1027, in _find_and_load
File "", line 1006, in _find_and_load_unlocked
File "", line 688, in _load_unlocked
File "pyimod02_importers.py", line 457, in exec_module
File "ossdbtoolsservice/mcp_server/main.py", line 18, in
File "", line 1027, in _find_and_load
File "", line 1006, in _find_and_load_unlocked
File "", line 688, in _load_unlocked
File "pyimod02_importers.py", line 457, in exec_module
File "ossdbtoolsservice/mcp_server/mcp_server.py", line 7, in
File "", line 1027, in _find_and_load
File "", line 1006, in _find_and_load_unlocked
File "", line 688, in _load_unlocked
File "pyimod02_importers.py", line 457, in exec_module
File "fastmcp/init.py", line 8, in
File "pydantic_settings/main.py", line 188, in init
File "pydantic/main.py", line 253, in init
pydantic_core._pydantic_core.ValidationError: 1 validation error for Settings
log_level
Input should be 'DEBUG', 'INFO', 'WARNING', 'ERROR' or 'CRITICAL' [type=literal_error, input_value='WARN', input_type=str]
For further information visit https://errors.pydantic.dev/2.11/v/literal_error
[PYI-11258:ERROR] Failed to execute script 'ossdbtoolsservice_main' due to unhandled exception!
[Error - 2:42:22 PM] Connection to server got closed. Server will not be restarted.

To Reproduce

Steps to reproduce the behavior:

1. Install the extension (last version 1.22.0)
2. Click on the extension's tab, in attempt to create a new connection.

Expected behavior

Well... just a starting extension where I could create a connection

VS Code version

Version: 1.120.0 (user setup)
Commit: 0958016b2af9f09bb4257e0df4a95e2f90590f9f
Date: 2026-05-12T20:17:22Z
Electron: 39.8.8
ElectronBuildId: 13870025
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.26100

[mmcfarland]

Thanks for this report @NicolasB-Pro! Was this a new install, or have you been using the extension previously? We'll take a look at seeing how this setting value might have gotten changed (and not making it a fatal error).

[NicolasB-Pro]

It's a new install on an already installed VS code (3 months old).

[mmcfarland]

Hi @NicolasB-Pro is it possible that you have loaded some ENV vars or similar for a project also using FastMCP. That library seems to be finding a setting it is looking for (not from our extension setting, but from your environment) with an incorrect value.

The failing value is read by FastMCP from its own configuration, most likely one of:

• FASTMCP_LOG_LEVEL=WARN in your user/system environment
• FASTMCP_LOG_LEVEL=WARN in a .env file
• FASTMCP_ENV_FILE pointing to a file containing that value

FastMCP accepts WARNING but rejects the alias WARN, and that validation happens very early while the tools service is importing, before the extension can show the connection UI.

As a workaround, please check whether FASTMCP_LOG_LEVEL is set. On Windows PowerShell:

[Environment]::GetEnvironmentVariable("FASTMCP_LOG_LEVEL", "User")
[Environment]::GetEnvironmentVariable("FASTMCP_LOG_LEVEL", "Machine")
$env:FASTMCP_LOG_LEVEL
$env:FASTMCP_ENV_FILE

If you find WARN, change it to WARNING or remove the setting.

We're adding a safety check in our code to normalize that value if it exists otherwise, but I'd like to find out the root cause of this value.

[NicolasB-Pro]

I might have another extension using FastMCP, i'm not sure.

Nothing seems set on my side :

PS C:\WINDOWS\system32> [Environment]::GetEnvironmentVariable("FASTMCP_LOG_LEVEL", "User")
PS C:\WINDOWS\system32> [Environment]::GetEnvironmentVariable("FASTMCP_LOG_LEVEL", "Machine")
PS C:\WINDOWS\system32> $env:FASTMCP_LOG_LEVEL
PS C:\WINDOWS\system32> $env:FASTMCP_ENV_FILE
PS C:\WINDOWS\system32> 

By the way i'm using WSL (Visual Studio is on my windows side) so it might be related.
Can't seem to find anything set in WSL either :

/mnt/c/WINDOWS/system32$ echo $FASTMCP_LOG_LEVEL

/mnt/c/WINDOWS/system32$

[chriszrc]

I get this in Mac OS as well:

Traceback (most recent call last):
  File "ossdbtoolsservice_main.py", line 16, in <module>
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "pyimod02_importers.py", line 457, in exec_module
  File "ossdbtoolsservice/mcp_server/__main__.py", line 19, in <module>
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "pyimod02_importers.py", line 457, in exec_module
  File "ossdbtoolsservice/mcp_server/mcp_server.py", line 7, in <module>
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "pyimod02_importers.py", line 457, in exec_module
  File "fastmcp/__init__.py", line 21, in <module>
  File "pydantic_settings/main.py", line 188, in __init__
  File "pydantic/main.py", line 253, in __init__
pydantic_core._pydantic_core.ValidationError: 1 validation error for Settings
log_level
  Input should be 'DEBUG', 'INFO', 'WARNING', 'ERROR' or 'CRITICAL' [type=literal_error, input_value='VERBOSE', input_type=str]
    For further information visit https://errors.pydantic.dev/2.11/v/literal_error
[PYI-35263:ERROR] Failed to execute script 'ossdbtoolsservice_main' due to unhandled exception!
[Error - 9:50:18 AM] Connection to server got closed. Server will not be restarted.

[mmcfarland]

Thanks @chriszrc -- same question for you, is there any reason that you might have some system level FastMCP settings set? I'll keep looking for a root cause here, and perhaps just try to ignore any values that may come from the system.

[chriszrc]

@mmcfarland if running this in vscode integrated terminal is enough echo $FASTMCP_LOG_LEVEL then no, nothing is set-