diff --git a/scripts/verify-no-legacy-data-source.sh b/scripts/verify-no-legacy-data-source.sh
index d4beaba..0477096 100755
--- a/scripts/verify-no-legacy-data-source.sh
+++ b/scripts/verify-no-legacy-data-source.sh
@@ -60,6 +60,25 @@ if [[ -n "$local_only_hits" ]]; then
   fail "legacy or local-only data source references are not allowed in fidc-backtest-engine runtime" "$local_only_hits"
 fi
 
+json_query_hits="$(
+  rg -n \
+    --glob '!**/.git/**' \
+    --glob '!**/target/**' \
+    --glob '!**/docs/**' \
+    --glob '!**/*.md' \
+    --glob '!**/tests/**' \
+    --glob '!**/*test*.rs' \
+    --glob '!crates/fidc-core/src/strategy_ai.rs' \
+    --glob '!scripts/verify-no-legacy-data-source.sh' \
+    '/v1/query/(source-rows|daily-execution-prices|minute-execution-prices|instruments|corporate-actions)\.json' \
+    crates Cargo.toml \
+    2>/dev/null || true
+)"
+
+if [[ -n "$json_query_hits" ]]; then
+  fail "JSON Source Lake high-throughput endpoints are not allowed in fidc-backtest-engine runtime; use Arrow endpoints" "$json_query_hits"
+fi
+
 fused_hits="$(
   rg -n \
     --glob '!**/.git/**' \