diff --git a/cabal.project b/cabal.project
index d8665fc91..c47f591dc 100644
--- a/cabal.project
+++ b/cabal.project
@@ -3,3 +3,9 @@ packages:
     cryptol-remote-api
     tests
     deps/argo/argo
+
+source-repository-package
+   type:     git
+   location: https://github.com/GaloisInc/what4.git
+   tag:      44000e2e8b5d658d199ff181dc07889125efd630
+   subdir:   what4
\ No newline at end of file