diff --git a/pkgs/build-support/node/prefetch-npm-deps/src/main.rs b/pkgs/build-support/node/prefetch-npm-deps/src/main.rs
index 7666474f9fe1..53cc075bfdc0 100644
--- a/pkgs/build-support/node/prefetch-npm-deps/src/main.rs
+++ b/pkgs/build-support/node/prefetch-npm-deps/src/main.rs
@@ -33,8 +33,42 @@ fn get_packument_url(registry: &str, package_name: &str) -> anyhow::Result<Url>
 
 /// Normalize packument data to ensure determinism.
 ///
-/// Strips volatile fields like `_rev`, `time`, and `modified`.
-/// Filters the `versions` map to only include versions requested in the lockfile.
+/// Filters to whitelisted fields and requested versions only.
+/// Allowed top-level fields in normalized packuments.
+///
+/// For lockfile-based installs, versions are exact (e.g., "4.17.21") so npm-pick-manifest
+/// just does a direct `versions[ver]` lookup. Tarballs are fetched via the resolved URL.
+const ALLOWED_TOP_LEVEL_FIELDS: &[&str] = &["name", "versions"];
+
+/// Allowed fields in version objects.
+///
+/// Based on analysis of pacote, npm-pick-manifest, npm-install-checks, and arborist.
+/// Only fields actually read during `npm install` are included.
+const ALLOWED_VERSION_FIELDS: &[&str] = &[
+    "name",
+    "version",
+    // Dependencies
+    "dependencies",
+    "devDependencies",
+    "peerDependencies",
+    "peerDependenciesMeta",
+    "optionalDependencies",
+    "bundleDependencies",
+    "bundledDependencies",
+    // Distribution (tarball URL and integrity)
+    "dist",
+    // Executables
+    "bin",
+    // Platform constraints (npm-install-checks)
+    "engines",
+    "os",
+    "cpu",
+    // Lifecycle scripts
+    "scripts",
+    // Version selection hint (npm-pick-manifest)
+    "deprecated",
+];
+
 fn normalize_packument(
     package_name: &str,
     data: &[u8],
@@ -47,37 +81,22 @@ fn normalize_packument(
         .as_object_mut()
         .ok_or_else(|| anyhow!("packument for {package_name} is not a JSON object"))?;
 
-    // Strip volatile top-level fields
-    obj.remove("_rev");
-    obj.remove("time");
-    obj.remove("modified");
+    // Keep only whitelisted top-level fields to ensure determinism
+    obj.retain(|key, _| ALLOWED_TOP_LEVEL_FIELDS.contains(&key.as_str()));
 
-    // Filter versions to only those in lockfile
+    // Filter and normalize versions
     if let Some(Value::Object(versions)) = obj.get_mut("versions") {
+        // Only keep versions that are in the lockfile
         versions.retain(|version, _| requested_versions.contains(version));
 
-        // Normalize each version object
+        // Normalize each version object to only include necessary fields
         for version_val in versions.values_mut() {
             if let Some(version_obj) = version_val.as_object_mut() {
-                // Strip fields starting with underscore (volatile/internal)
-                version_obj.retain(|key, _| !key.starts_with('_'));
-                // Strip other often-volatile fields
-                version_obj.remove("gitHead");
+                version_obj.retain(|key, _| ALLOWED_VERSION_FIELDS.contains(&key.as_str()));
             }
         }
     }
 
-    // Filter dist-tags to only point to versions we kept
-    if let Some(Value::Object(tags)) = obj.get_mut("dist-tags") {
-        tags.retain(|_, version_val| {
-            if let Some(version) = version_val.as_str() {
-                requested_versions.contains(version)
-            } else {
-                false
-            }
-        });
-    }
-
     serde_json::to_vec(&json)
         .map_err(|e| anyhow!("failed to re-serialize packument for {package_name}: {e}"))
 }