diff --git a/tools/build/missing-commits.pl6 b/tools/build/missing-commits.pl6
new file mode 100644
index 00000000000..92e1eed0d1d
--- /dev/null
+++ b/tools/build/missing-commits.pl6
@@ -0,0 +1,27 @@
+
+# Helper sub: for a line, return commit ID or Nil
+sub commit($line) { $line.starts-with('commit ') ?? $line.substr(7,8) !! Nil }
+
+# The commit that did the last VERSION bump
+my $version-bump-commit = commit( qx/git log -- VERSION/.lines.head );
+
+# Make a SetHash with all of the commits since the last VERSION bump
+my %commits is SetHash = qx/git log/.lines.map( {
+    if commit($_) -> \commit {
+        last if commit eq $version-bump-commit;
+        commit
+    }
+} );
+
+# Remove the commits that have been documented in ChangeLog since bump
+# Note that we assume here that an empty line indicates boundary between
+# releases.
+%commits{ "docs/ChangeLog".IO.lines.map( {
+    $_
+      ?? |.comb( / <?after \[> ( <[ 0..9 a..f A..F ]> ** 8 ) <?before \]> / )
+      !! last
+} ) }:delete;
+
+# Let the world know the result
+say "%commits.elems() commits not yet documented in ChangeLog:";
+%commits.keys.sort.batch(9).map: *.Str.say;