diff --git a/doc/04-schema.md b/doc/04-schema.md
index ea0d502a5..d096ad3b5 100644
--- a/doc/04-schema.md
+++ b/doc/04-schema.md
@@ -321,6 +321,9 @@ The following options are supported:
   different directory if you want to.
 * **bin-dir:** Defaults to `vendor/bin`. If a project includes binaries, they
   will be symlinked into this directory.
+* **process-timeout:** Defaults to `60`. The duration processes like git clones
+  can run before Composer assumes they died out. You may need to make this
+  higher if you have a slow connection or huge vendors.
 
 Example: