diff --git a/compiler/describe/analyze.go b/compiler/describe/analyze.go
index 77fd679c6..b037df310 100644
--- a/compiler/describe/analyze.go
+++ b/compiler/describe/analyze.go
@@ -165,7 +165,7 @@ func describeOpAggs(op dag.Op, parents []field.List) []field.List {
 		// not nil.
 		keys := field.List{}
 		for _, k := range op.Keys {
-			keys = append(keys, k.LHS.(*dag.ThisExpr).Path)
+			keys = append(keys, k.RHS.(*dag.ThisExpr).Path)
 		}
 		return []field.List{keys}
 	case *dag.ForkOp:
diff --git a/service/ztests/query-describe.yaml b/service/ztests/query-describe.yaml
index 1d5871a3c..b9e632852 100644
--- a/service/ztests/query-describe.yaml
+++ b/service/ztests/query-describe.yaml
@@ -89,7 +89,7 @@ outputs:
             "name": "main",
             "aggregation_keys": [
               [
-                "key1"
+                "v1"
               ],
               [
                 "key2"