diff --git a/ai-compliance-sdk/Dockerfile b/ai-compliance-sdk/Dockerfile
index 03c7384e..b87ea258 100644
--- a/ai-compliance-sdk/Dockerfile
+++ b/ai-compliance-sdk/Dockerfile
@@ -35,6 +35,8 @@ COPY policies/ ./policies/
 
 # Copy Compliance Execution Graph data (file-backed: Registry join-key copy + accepted control
 # mappings + evidence requirements) consumed by GET /sdk/v1/compliance/obligation-status.
+# data/obligations/obligation_join_keys.json is a synced copy of the repo-root Registry contract
+# (the Obligation Registry owns the canonical file) — re-sync it when the Registry grows.
 COPY data/control_mappings/ ./data/control_mappings/
 COPY data/evidence_requirements/ ./data/evidence_requirements/
 COPY data/obligations/ ./data/obligations/