diff --git a/README.md b/README.md
index c251603..12ff0f5 100644
--- a/README.md
+++ b/README.md
@@ -154,3 +154,17 @@ This extension is based on the [Template for VS Code Python tools extensions](ht
 - To automatically format the codebase, run: `just fmt`.
 - To run lint and type checks, run: `just check`.
 - To run tests, run: `just test`.
+
+To run the extension, navigate to `src/extension.ts` and run (`F5`). You should see the LSP output
+and Python log messages in the debug console under "Python Server".
+
+### Modifying the LSP
+
+- Clone [ruff-lsp](https://github.com/charliermarsh/ruff-lsp) to e.g. `../ruff-lsp`
+- Go to `../ruff-lsp` and run `pip install -t ../ruff-vscode/bundled/libs/ -e .`
+
+### Custom ruff build
+
+- Clone [ruff](https://github.com/charliermarsh/ruff) to e.g. `/home/ferris/ruff`
+- `cargo build` in ruff
+- In the settings, add `/home/ferris/ruff/target/debug/ruff` to "Ruff: Path"
diff --git a/bundled/tool/server.py b/bundled/tool/server.py
index 35f7dec..eba7078 100755
--- a/bundled/tool/server.py
+++ b/bundled/tool/server.py
@@ -2,30 +2,68 @@
 
 from __future__ import annotations
 
+import logging
+import logging.config
 import os
 import pathlib
+import site
 import sys
 
 BUNDLE_DIR = pathlib.Path(__file__).parent.parent
+logger = logging.getLogger(__name__)
 
 
 # Update sys.path before importing any bundled libraries.
 def update_sys_path(path_to_add: str) -> None:
     """Add given path to `sys.path`."""
     if path_to_add not in sys.path and os.path.isdir(path_to_add):
+        # site adds the directory at the end if it is not yet present, we want it to
+        # be front
         sys.path.insert(0, path_to_add)
+        # Allow dev installs into bundled/libs
+        site.addsitedir(path_to_add)
 
 
-# Ensure that we can import LSP libraries, and other bundled libraries.
-update_sys_path(os.fspath(BUNDLE_DIR / "libs"))
+def main():
+    import ruff_lsp
+    from ruff_lsp import server
 
+    logging.config.dictConfig(
+        {
+            "version": 1,
+            "disable_existing_loggers": False,
+            "formatters": {
+                "simple": {"format": "%(asctime)s %(levelname)-4s %(message)s"}
+            },
+            "handlers": {
+                "stderr": {
+                    "class": "logging.StreamHandler",
+                    "formatter": "simple",
+                },
+            },
+            "root": {"level": "INFO", "handlers": ["stderr"]},
+            "loggers": {
+                # Don't repeat every message
+                "pygls.protocol": {
+                    "level": "WARN",
+                    "handlers": ["stderr"],
+                    "propagate": False,
+                },
+            },
+        }
+    )
 
-# Start the server.
-if __name__ == "__main__":
-    from ruff_lsp import server
+    logger.info(f"ruff path: {ruff_lsp.__file__}, sys.path: {sys.path}")
 
     if not hasattr(server, "set_bundle"):
         raise RuntimeError("ruff-vscode needs at least ruff-lsp v0.0.6")
 
     server.set_bundle(os.fspath(BUNDLE_DIR / "libs" / "bin" / server.TOOL_MODULE))
     server.start()
+
+
+# Start the server.
+if __name__ == "__main__":
+    # Ensure that we can import LSP libraries, and other bundled libraries.
+    update_sys_path(os.fspath(BUNDLE_DIR / "libs"))
+    main()