diff --git a/Validation/nightly/offSpill_00.fcl b/Validation/nightly/offSpill_00.fcl
new file mode 100644
index 00000000..707677aa
--- /dev/null
+++ b/Validation/nightly/offSpill_00.fcl
@@ -0,0 +1,5 @@
+#include "Production/Validation/offSpill.fcl"
+source.fileNames : [
+"root://fndcadoor.fnal.gov:1094/mu2e/tape/phy-sim/dig/mu2e/CosmicSignalOffSpill/MDC2025an_best_v1_1/art/fd/03/dig.mu2e.CosmicSignalOffSpill.MDC2025an_best_v1_1.001430_00000013.art"
+]
+outputs.CentralHelixOutput.fileName: "offSpill_00.art"
diff --git a/Validation/nightly/offSpill_01.fcl b/Validation/nightly/offSpill_01.fcl
new file mode 100644
index 00000000..925e7838
--- /dev/null
+++ b/Validation/nightly/offSpill_01.fcl
@@ -0,0 +1,5 @@
+#include "Production/Validation/offSpill.fcl"
+source.fileNames : [
+"root://fndcadoor.fnal.gov:1094/mu2e/tape/phy-sim/dig/mu2e/CosmicSignalOffSpill/MDC2025an_best_v1_1/art/ca/ea/dig.mu2e.CosmicSignalOffSpill.MDC2025an_best_v1_1.001430_00000198.art"
+]
+outputs.CentralHelixOutput.fileName: "offSpill_01.art"
diff --git a/Validation/nightly/offSpill_02.fcl b/Validation/nightly/offSpill_02.fcl
new file mode 100644
index 00000000..4cb1d6f5
--- /dev/null
+++ b/Validation/nightly/offSpill_02.fcl
@@ -0,0 +1,5 @@
+#include "Production/Validation/offSpill.fcl"
+source.fileNames : [
+"root://fndcadoor.fnal.gov:1094/mu2e/tape/phy-sim/dig/mu2e/CosmicSignalOffSpill/MDC2025an_best_v1_1/art/37/ef/dig.mu2e.CosmicSignalOffSpill.MDC2025an_best_v1_1.001430_00001505.art"
+]
+outputs.CentralHelixOutput.fileName: "offSpill_02.art"
diff --git a/Validation/nightly/offSpill_03.fcl b/Validation/nightly/offSpill_03.fcl
new file mode 100644
index 00000000..a013c388
--- /dev/null
+++ b/Validation/nightly/offSpill_03.fcl
@@ -0,0 +1,5 @@
+#include "Production/Validation/offSpill.fcl"
+source.fileNames : [
+"root://fndcadoor.fnal.gov:1094/mu2e/tape/phy-sim/dig/mu2e/CosmicSignalOffSpill/MDC2025an_best_v1_1/art/11/12/dig.mu2e.CosmicSignalOffSpill.MDC2025an_best_v1_1.001430_00002687.art"
+]
+outputs.CentralHelixOutput.fileName: "offSpill_03.art"
diff --git a/Validation/nightly/offSpill_04.fcl b/Validation/nightly/offSpill_04.fcl
new file mode 100644
index 00000000..fd970e7d
--- /dev/null
+++ b/Validation/nightly/offSpill_04.fcl
@@ -0,0 +1,5 @@
+#include "Production/Validation/offSpill.fcl"
+source.fileNames : [
+"root://fndcadoor.fnal.gov:1094/mu2e/tape/phy-sim/dig/mu2e/CosmicSignalOffSpill/MDC2025an_best_v1_1/art/27/ab/dig.mu2e.CosmicSignalOffSpill.MDC2025an_best_v1_1.001430_00020461.art"
+]
+outputs.CentralHelixOutput.fileName: "offSpill_04.art"
diff --git a/Validation/offSpill.fcl b/Validation/offSpill.fcl
new file mode 100644
index 00000000..8493bdd6
--- /dev/null
+++ b/Validation/offSpill.fcl
@@ -0,0 +1,50 @@
+#
+# Off-spill cosmic reconstruction for nightly validation: the only nightly job that runs the CentralHelix fit (KKCHmu)
+# and its extrapolation to the CRV, and that validates the LoopHelix fits (KKDe, KKUe, KKDmu, KKUmu) on cosmics.
+#
+#include "Production/JobConfig/recoMC/OffSpill.fcl"
+# the inputs are Sim_best v1_1 digis; v1_1 and this v1_5 resolve to identical conditions for their run (1430)
+#include "Production/Validation/database.fcl"
+#
+# CHFilter gates only the CentralHelix output (every event is still fitted) and passes ~0.5% of off-spill cosmics,
+# too few tracks for the nightly comparison, so pass every event
+#
+physics.filters.CHFilter : {
+  module_type : FixedFilter
+  ReturnValue : true
+}
+#
+# the nightly validates one file per job: write the CentralHelix and LoopHelix products (both paths run the same
+# reconstruction, and with CHFilter bypassed CHPath selects every event) to the CentralHelix output
+#
+outputs.LoopHelixOutput.fileName : "/dev/null"
+outputs.CentralHelixOutput.fileName : "mcs.owner.val-offSpill.dsconf.seq.art"
+outputs.CentralHelixOutput.outputCommands : [
+  "drop *_*_*_*",
+  "keep mu2e::TriggerInfo_*_*_*",
+  "keep art::TriggerResults_*_*_*",
+  "keep mu2e::KalSeeds_KK*_*_*",
+  "keep mu2e::HelixSeeds_MH*_*_*",
+  "keep mu2e::TimeClusters_MH*_*_*",
+  "keep mu2e::CosmicTrackSeeds_LineFinder_*_*",
+  "keep mu2e::TimeClusters_SimpleTimeCluster_*_*",
+  "keep mu2e::CaloClusters_CaloClusterMaker_*_*",
+  "keep mu2e::CrvCoincidenceClusters_*_*_*",
+  "keep mu2e::EventWindowMarker_*_*_*",
+  "keep mu2e::ProtonBunchTime_*_*_*",
+  "keep *_SelectReco*_*_*",
+  "keep *_genCounter_*_*",
+  "keep mu2e::StageNormalization_*_*_*",
+  "keep mu2e::PrimaryParticle_*_*_*",
+  "keep mu2e::StatusG4_*_*_*",
+  "keep mu2e::ProtonBunchIntensity_*_*_*",
+  "keep mu2e::ProtonBunchTimeMC_*_*_*",
+  "keep mu2e::EventWeight_*_*_*",
+  "keep *_compressRecoMCs_*_*"
+]
+# 10000 events takes 40-90 minutes on current grid nodes
+source.maxEvents : 10000
+# print summaries
+services.scheduler.wantSummary: true
+services.TimeTracker.printSummary: true
+services.TFileService.fileName : "/dev/null"