diff --git a/.golangci.yml b/.golangci.yml
index 149605098..32e3fa3cd 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -40,6 +40,15 @@ linters:
       - ^docs/
       - ^deploy/
       - ^skills/
+    rules:
+      # Upstream rrule-go v1.8.2's own dead store (`lno1wkst = 0`), vendored
+      # verbatim. Excluded narrowly instead of editing upstream code, so every
+      # other linter still checks our budget/stall delta in the same file
+      # (TASK-4100 lint ruling; see the package's PROVENANCE.md).
+      - path: ^internal/schedule/internal/rrule/rrule\.go$
+        linters:
+          - ineffassign
+        text: lno1wkst
 
 formatters:
   enable:
diff --git a/internal/schedule/internal/rrule/PROVENANCE.md b/internal/schedule/internal/rrule/PROVENANCE.md
index cc897c527..6b380639a 100644
--- a/internal/schedule/internal/rrule/PROVENANCE.md
+++ b/internal/schedule/internal/rrule/PROVENANCE.md
@@ -25,6 +25,10 @@ The differences from upstream marked TASK-4100 in rrule.go are:
 rruleset.go, str.go, util.go and LICENSE are byte-identical to upstream: their
 sha256 matches the table below. rrule.go is the only modified file.
 
+Lint: .golangci.yml excludes one upstream finding, ineffassign on `lno1wkst = 0`
+in rrule.go (upstream's own dead store), rather than editing upstream code. Every
+other linter still runs on this package, including our delta (TASK-4100 lint ruling).
+
 ## File count
 
 The brief for this work said 3 library files; there are 4 (rrule.go, rruleset.go,