diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index e12a24fa4..d76adea7e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -39,6 +39,7 @@ jobs:
       - uses: actions/setup-python@v6
         with:
           python-version: '3.14'
+      - uses: SublimeText/UnitTesting/actions/setup@v1
       - run: pip3 install tox --user
       - run: echo "$HOME/.local/bin" >> $GITHUB_PATH
       - run: tox
diff --git a/pyproject.toml b/pyproject.toml
index c7789a0a6..ebcdb1e92 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,8 +16,8 @@ deps = [
     "orjson==3.11.4",
 ]
 commands = [
-    ["pyright", "plugin", "stubs"],
-    ["ruff", "check"],
+    ["python", "scripts/run_with_modified_python_path.py", "python314", "pyright", "plugin", "stubs"],
+    ["python", "scripts/run_with_modified_python_path.py", "python314", "ruff", "check"],
 ]
 
 [tool.ruff]
@@ -45,9 +45,10 @@ order-by-type = false
 required-imports = ["from __future__ import annotations"]
 
 [tool.ruff.lint.per-file-ignores]
+"plugin/core/protocol.py" = ["UP006", "UP007"]
 "plugin/core/typing.py" = ["F401"]
 "protocol/__init__.py" = ["D400", "D415"]
-"plugin/core/protocol.py" = ["UP006", "UP007"]
+"scripts/*.py" = ["INP001"]
 
 [tool.ruff.lint]
 # Enable preview rules.
diff --git a/scripts/run_with_modified_python_path.py b/scripts/run_with_modified_python_path.py
new file mode 100644
index 000000000..059f8526b
--- /dev/null
+++ b/scripts/run_with_modified_python_path.py
@@ -0,0 +1,40 @@
+"""
+Wrapper script for setting the PYTHONPATH env var to Sublime's Lib/pythonXY directory.
+
+This is used for tools like pyright and ruff that can then discover third-party libraries.
+See the pyproject.toml file for usage of this script.
+
+The first argument to this script should be the python directory name inside of Sublime's Lib/ directory.
+For instance, it can be "python38" or "python314".
+
+The rest of the arguments are passed unmodified to subprocess.call.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+import os
+import platform
+import subprocess
+import sys
+
+if platform.system() == "Windows":
+    config_root = Path.home() / "AppData" / "Roaming"
+elif platform.system() == "Darwin":
+    config_root = Path.home() / "Library" / "Application Support"
+else:
+    config_root = Path.home() / ".config"
+
+for dirname in ("sublime-text-3", "sublime-text"):
+    candidate = config_root / dirname
+    if candidate.is_dir():
+        sublime_dir = candidate
+        break
+else:
+    raise RuntimeError(f"Could not find either 'sublime-text-3' or 'sublime-text' under {config_root}")
+
+lib_dir = sublime_dir / "Lib" / sys.argv[1]
+env = os.environ.copy()
+env["PYTHONPATH"] = str(lib_dir)
+print("modified PYTHONPATH:", env["PYTHONPATH"])
+raise SystemExit(subprocess.call(sys.argv[2:], env=env))