diff --git a/sweep-wns.tcl b/sweep-wns.tcl
index f896420..632c6bf 100644
--- a/sweep-wns.tcl
+++ b/sweep-wns.tcl
@@ -7,6 +7,8 @@ set paths [find_timing_paths -path_group reg2reg -sort_by_slack -group_count 1]
 set path [lindex $paths 0]
 set slack [get_property $path slack]
 
-puts "slack: $slack"
-report_tns
-report_cell_usage
+set f [open $::env(OUTPUT) w]
+puts $f "slack: $slack"
+close $f
+report_tns >> $::env(OUTPUT)
+report_cell_usage >> $::env(OUTPUT)
diff --git a/sweep.bzl b/sweep.bzl
index 15b3a2e..d00f06c 100644
--- a/sweep.bzl
+++ b/sweep.bzl
@@ -89,9 +89,9 @@ def orfs_sweep(
             ],
             arguments = {
                 "ODB_FILE": "$(location :" + name + "_" + variant + "_odb)",
+                "OUTPUT": "$(location :" + name + "_" + variant + ".txt)",
             },
             data = [":" + name + "_" + variant + "_odb"],
-            extra_args = "> $WORK_HOME/" + name + "_" + variant + ".txt",
             script = Label(":sweep-wns.tcl"),
             visibility = visibility,
         )