diff --git a/openspec/changes/deterministic-gateway-sbom/tasks.md b/openspec/changes/deterministic-gateway-sbom/tasks.md
index 5816315..193de58 100644
--- a/openspec/changes/deterministic-gateway-sbom/tasks.md
+++ b/openspec/changes/deterministic-gateway-sbom/tasks.md
@@ -10,5 +10,5 @@
 
 ## 3. Verification
 
-- [ ] 3.1 Prove byte-stable regeneration and rejection of dirty, missing, mismatched, or ambiguous inputs
+- [x] 3.1 Prove byte-stable regeneration and rejection of dirty, missing, mismatched, or ambiguous inputs
 - [x] 3.2 Reconcile the deployment-artifact canonical spec and run strict validation