diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 428298290..b69356013 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -47,7 +47,7 @@ Testing uv requires multiple specific Python versions; they can be installed wit
 cargo run python install
 ```
 
-The storage directory can be configured with `UV_PYTHON_INSTALL_DIR`.
+The storage directory can be configured with `UV_PYTHON_INSTALL_DIR`. (It must be an absolute path.)
 
 ### Snapshot testing
 
diff --git a/crates/uv/tests/it/help.rs b/crates/uv/tests/it/help.rs
index c55b70819..2aeeb9ea2 100644
--- a/crates/uv/tests/it/help.rs
+++ b/crates/uv/tests/it/help.rs
@@ -1,3 +1,5 @@
+use uv_static::EnvVars;
+
 use crate::common::{uv_snapshot, TestContext};
 
 #[test]
@@ -452,7 +454,7 @@ fn help_subcommand() {
 fn help_subsubcommand() {
     let context = TestContext::new_with_versions(&[]);
 
-    uv_snapshot!(context.filters(), context.help().arg("python").arg("install"), @r###"
+    uv_snapshot!(context.filters(), context.help().env_remove(EnvVars::UV_PYTHON_INSTALL_DIR).arg("python").arg("install"), @r###"
     success: true
     exit_code: 0
     ----- stdout -----