Python Jedi LSP error: Unsupported position encoding (PositionEncodingKind.Utf16) in VSCodium #351
Description
Hello,
I’m experiencing a persistent problem with the Python extension in VSCodium when using the Jedi language server. The Python language server fails to initialize and keeps restarting, with the following error in the Output panel:
text
Server initialization failed.
Error: Unsupported position encoding (PositionEncodingKind.Utf16) received from server Python Jedi
at P.doInitialize (...\ms-python.python-2025.20.1-universal\out\client\extension.js:2:2084342)
at async P.start (...\ms-python.python-2025.20.1-universal\out\client\extension.js:2:2083020)
at async l.start (...\ms-python.python-2025.20.1-universal\out\client\extension.js:2:22276)
[...]
The Python Jedi server crashed 5 times in the last 3 minutes. The server will not be restarted.
From the source code, it looks like the client does a strict check on result.capabilities.positionEncoding:
ts
if (result.capabilities.positionEncoding !== undefined &&
result.capabilities.positionEncoding !== PositionEncodingKind.UTF16) {
throw new Error(Unsupported position encoding (${result.capabilities.positionEncoding}) received from server ${this.name});
}
In my case the server reports PositionEncodingKind.Utf16, and the client still throws and stops the server.
Environment:
Editor: VSCodium (latest stable at the time of writing)
Python extension: ms-python.python-2025.20.1-universal
OS: Windows 10 x64
Python versions installed: 3.11, 3.12, 3.13, 3.14, 3.15 (user installs)
Active interpreter in workspace: Python 3.12 (venv)
Steps to reproduce:
Install VSCodium.
Install the official Python extension (ms-python.python) from VSIX.
Open any Python project and let the extension start the Jedi language server (default settings).
Check the “Python” Output channel: the error above is printed, and language features do not work.
What I tried:
Toggling python.jediEnabled and python.languageServer settings.
Disabling other Python‑related extensions.
Creating a fresh workspace and venv.
The problem persists as long as the Jedi LSP client is enabled.
Questions:
Is this a known compatibility issue between the current Python extension and the Jedi language server in VSCodium?
Is there a recommended workaround (other than completely disabling the Python language server), e.g. a specific version of the extension or a configuration that relaxes the positionEncoding check?
Are there any plans to support PositionEncodingKind.Utf16 (or to make the check more tolerant) in future releases?
Any guidance would be appreciated. I’m setting up a public Python project and would like to keep using VSCodium if possible.
Thank you!
Best regards,