diff --git a/josh-sync.toml b/josh-sync.toml
index ebdb457628..eeeb82659a 100644
--- a/josh-sync.toml
+++ b/josh-sync.toml
@@ -1,3 +1,7 @@
 org = "rust-lang"
 repo = "stdarch"
 path = "library/stdarch"
+
+[[post-pull]]
+cmd = ["cargo", "fmt"]
+commit-message = "Run `cargo fmt`"