diff --git a/src/python/pants/backend/python/subsystems/python_tool_base.py b/src/python/pants/backend/python/subsystems/python_tool_base.py
index 4eacb4e8349..36125434518 100644
--- a/src/python/pants/backend/python/subsystems/python_tool_base.py
+++ b/src/python/pants/backend/python/subsystems/python_tool_base.py
@@ -124,7 +124,9 @@ def _install_from_resolve_help(cls) -> str:
 
             Values can be pip-style requirements (e.g., `tool` or `tool==1.2.3` or `tool>=1.2.3`),
             or addresses of `python_requirement` targets (or targets that generate or depend on
-            `python_requirement` targets).
+            `python_requirement` targets). Make sure to use the `//` prefix to refer to targets
+            using their full address from the root (e.g. `//3rdparty/python:tool`). This is necessary
+            to distinguish address specs from local or VCS requirements.
 
             The lockfile will be validated against the requirements - if a lockfile doesn't
             provide the requirement (at a suitable version, if the requirement specifies version