Cursor: Python + Ansible extension compatibility fix (PET binary, pinned Python 2024.20.0)

cursor-python-ansible-extensions.md

Cursor: Python + Ansible Extension Compatibility

Notes for fixing extension activation failures and Python environment warnings when using Ansible 26.6+, Python Environments, and ms-python.python in Cursor on macOS.

Tested on Cursor ~1.105 (VS Code 1.105 base), macOS arm64, June 2026.

Symptoms

• Notification: "Extension activation failed" — root cause is usually ms-python.python
• Log error:

  TypeError: Cannot read properties of undefined (reading 'onDidChangeEnvironment')
    at createEnvExtApi (ms-python.python-2025.6.1)
  

• Ansible warning: "Python environment discovery is degraded (PET binary missing). This commonly occurs in OpenVSX-based editors (Dev Spaces, VSCodium)."
• Ansible prompt: "The Python Environments extension requires 'python.useEnvironmentsExtension' to be enabled..."

Root cause

Three extensions interact badly in Cursor:

Extension	Issue
ms-python.python 2025.6.x	Calls Python Environments API during activation; crashes in Cursor's extension host
ms-python.vscode-python-envs	Required by Ansible 26.6+; OpenVSX universal build omits native PET binary
redhat.ansible 26.6+	Hard-depends on both extensions above; checks for PET in python-envs install dir

Not the cause: Pylance capped at 2024.8.1 in Cursor — that is expected, not a bug.

Ansible cannot uninstall ms-python.vscode-python-envs — it is a declared dependency:

"extensionDependencies": [
  "ms-python.python",
  "ms-python.vscode-python-envs",
  "redhat.vscode-yaml"
]

Fix

1. Downgrade and pin Python extension

Install a version before the broken envs API integration:

cursor --install-extension ms-python.python@2024.20.0

Verify:

cursor --list-extensions --show-versions | rg ms-python.python
# ms-python.python@2024.20.0

Pin it so Cursor does not auto-upgrade back to 2025.6.x:

1. Extensions → Python → gear icon → Disable Auto Update
2. Confirm "pinned": true in ~/.cursor/extensions/extensions.json for ms-python.python

If upgraded accidentally, reinstall:

cursor --install-extension ms-python.python@2024.20.0

2. Provide PET binary for Python Environments (OpenVSX workaround)

OpenVSX universal builds of ms-python.vscode-python-envs lack python-env-tools/bin/pet. Ansible checks for PET in the python-envs extension directory, not the Python extension directory.

Copy PET from the (platform-specific) Python extension, or from a prior install:

PYTHON_EXT="$HOME/.cursor/extensions/ms-python.python-2024.20.0"
ENVS_EXT="$HOME/.cursor/extensions/ms-python.vscode-python-envs-1.10.0-universal"

mkdir -p "$PYTHON_EXT/python-env-tools/bin"
# if pet missing in 2024.20.0, copy from an older darwin-arm64 python extension:
# cp "$HOME/.cursor/extensions/ms-python.python-2025.6.1-darwin-arm64/python-env-tools/bin/pet" \
#    "$PYTHON_EXT/python-env-tools/bin/pet"
chmod +x "$PYTHON_EXT/python-env-tools/bin/pet"

mkdir -p "$ENVS_EXT/python-env-tools/bin"
ln -sf "$PYTHON_EXT/python-env-tools/bin/pet" "$ENVS_EXT/python-env-tools/bin/pet"

Note: Re-do this symlink after Python Environments or Python extension updates.

3. Cursor user settings

Add to ~/Library/Application Support/Cursor/User/settings.json:

{
  "python.defaultInterpreterPath": "/opt/homebrew/bin/python3",
  "python.useEnvironmentsExtension": true,
  "ansible.python.interpreterPath": "/opt/homebrew/bin/python3"
}

Do not put a repo-specific .venv path in global user settings — it applies to every workspace. With useEnvironmentsExtension enabled, Python Environments auto-selects .venv when present in the open project.

For repo-specific overrides, use .vscode/settings.json in that repo only.

4. Reload

Cmd+Shift+P → Developer: Reload Window

Expected result

• No "Extension activation failed" for ms-python.python
• No Ansible PET degraded warning
• Terminal auto-activation of .venv in repos that have one
• Ansible, Python, and Python Environments all remain installed

Extension versions (working set)

ms-python.python@2024.20.0          # pinned
ms-python.vscode-python-envs@1.10.0 # required by Ansible; do not remove
ms-python.vscode-pylance@2024.8.1   # latest Cursor allows
redhat.ansible@26.6.0

Debugging

Extension host log:

~/Library/Application Support/Cursor/logs/<latest>/window1/exthost/exthost.log

Python extension output:

~/Library/Application Support/Cursor/logs/<latest>/window1/exthost/ms-python.python/Python.log

Python Environments output:

~/Library/Application Support/Cursor/logs/<latest>/window1/exthost/ms-python.vscode-python-envs/Python Environments.log

Look for:

• Extension activation failure: ms-python.python
• [Ansible] PET binary check: ... — missing
• [pet] Starting Python Locator ...

Unrelated noise (safe to ignore)

Message	Cause
MCP spawn npx ENOENT	Cursor cannot find npx in PATH when launched from Dock
GitLens Could not resolve hashgraph/infrastructure	GitHub API / repo access, not extension activation

When this workaround can be removed

When Cursor upgrades its underlying VS Code base enough that:

• ms-python.python 2025.6+ activates cleanly with ms-python.vscode-python-envs
• OpenVSX or marketplace ships platform-specific python-envs builds with PET included

Until then, keep Python pinned at 2024.20.0.

References

• Ansible VS Code extension
• Python Environments extension
• vscode-python issue #25820 (env discovery / OpenVSX)
• Cursor forum: Python Environments compatibility