update doc/decicions/validation.md
@@ -66,7 +66,11 @@ of each key to the corresponding validation plugin.
## Implications
-- validation plugins have to export their validation routine
+validation plugins have to export their validation routine
+
+`static int validateKey(const Key * key, const Key * errorKey)`
+
+returning 1 if validation succeeded, 0 on failure
## Related decisions
