ci(vt-gate): name the engine that flagged, not just the count

scripts/ci/check-virustotal.sh

@@ -38,7 +38,12 @@ echo "$VT_ANALYSIS" | tr ',' '\n' | while IFS= read -r entry; do
       continue
     fi
 
-    STATS=$(echo "$RESULT" | python3 -c "
+    # Line 1 is the CSV summary; any further lines name a flagging engine.
+    # The engine names are what a detection is actionable ON: the FP submission
+    # has to go to a specific vendor, and "is this the known-noisy one or a new
+    # family" is the first question asked. Reporting only counts sent the reader
+    # to the web UI for the one fact the gate already had in hand.
+    REPORT=$(echo "$RESULT" | python3 -c "
 import json, sys
 d = json.loads(sys.stdin.read())
 attrs = d.get('data', {}).get('attributes', {})
@@ -51,8 +56,16 @@ harmless = stats.get('harmless', 0)
 total = sum(stats.values())
 completed = malicious + suspicious + undetected + harmless
 print(f'{status},{malicious},{suspicious},{completed},{total}')
+for engine, r in sorted((attrs.get('results') or {}).items()):
+    if r.get('category') in ('malicious', 'suspicious'):
+        label = r.get('result') or r.get('category')
+        version = r.get('engine_version') or '?'
+        updated = r.get('engine_update') or '?'
+        print(f'{engine} = {label} (engine {version}, defs {updated})')
 " 2>/dev/null || echo "queued,0,0,0,0")
 
+    STATS=$(echo "$REPORT" | head -1)
+    DETECTIONS=$(echo "$REPORT" | tail -n +2)
     STATUS=$(echo "$STATS" | cut -d',' -f1)
     MALICIOUS=$(echo "$STATS" | cut -d',' -f2)
     SUSPICIOUS=$(echo "$STATS" | cut -d',' -f3)
@@ -66,6 +79,16 @@ print(f'{status},{malicious},{suspicious},{completed},{total}')
       fi
       if [ "$MALICIOUS" -gt 0 ] || [ "$SUSPICIOUS" -gt 0 ]; then
         echo "BLOCKED: $BASENAME flagged ($MALICIOUS malicious, $SUSPICIOUS suspicious / $COMPLETED engines)"
+        if [ -n "$DETECTIONS" ]; then
+          echo "$DETECTIONS" | while IFS= read -r detection; do
+            [ -n "$detection" ] && echo "  detected by: $detection"
+          done
+        else
+          # Counts say something flagged but no engine is named: report that
+          # rather than printing nothing, so the gap is visible instead of
+          # looking like a detection-free block.
+          echo "  detected by: <engine names unavailable in the analysis response>"
+        fi
         echo "  $URL"
         echo "FAIL" >> /tmp/vt_gate_fail
       else

tests/test_vt_gate_zero_tolerance_contract.sh

@@ -50,6 +50,19 @@ mk_response clean 0 0
 mk_response one_malicious 1 0
 mk_response one_suspicious 0 1
 
+# Same detection as one_malicious, but carrying the per-engine results a real
+# analysis returns. Pins that the gate NAMES the engine that fired.
+cat > "$FIX/responses/named_engine.json" <<'EOF'
+{"data":{"attributes":{"status":"completed",
+  "stats":{"malicious":1,"suspicious":0,"undetected":60,"harmless":0},
+  "results":{
+    "Microsoft":{"category":"malicious","result":"Trojan:Win32/Wacatac.B!ml",
+                 "engine_version":"1.1.24010.10","engine_update":"20260807"},
+    "Kaspersky":{"category":"undetected","result":null,
+                 "engine_version":"22.0.1.28","engine_update":"20260807"}
+  }}}}
+EOF
+
 echo "release-bytes" > "$FIX/work/binaries/probe"
 
 run_gate() { # version analysis-id -> echoes exit code
@@ -74,5 +87,28 @@ for version in v0.9.1 v0.9.1-rc.1 v0.9.1-pre1 v1.0.0-alpha.1; do
     fail "1 suspicious must block on $version"
 done
 
+# A detection must NAME the engine that fired.
+#
+# The gate reported counts only ("1 malicious / 59 engines"), which is the one
+# thing a reader cannot act on: a false-positive submission goes to a SPECIFIC
+# vendor (and the WDSI developer path is a web form, so there is no API to guess
+# with), and triage starts with "known-noisy engine, or a new family?". In the
+# 2026-08-07 dry run three artifacts flagged and the logs could not say by what,
+# so the answer had to be fetched by hand from the web UI afterwards.
+[ "$(run_gate v0.9.1 named_engine)" != "0" ] || fail "named-engine detection must still block"
+grep -q "Microsoft" "$FIX/last.log" || \
+  fail "gate must name the flagging engine (Microsoft) — got: $(cat "$FIX/last.log")"
+grep -q "Trojan:Win32/Wacatac.B!ml" "$FIX/last.log" || \
+  fail "gate must report the detection label, not just the vendor"
+# Engines that did NOT flag must not be listed, or the actionable line drowns.
+if grep -q "detected by: Kaspersky" "$FIX/last.log"; then
+  fail "gate listed a non-flagging engine (Kaspersky) as a detection"
+fi
+
+# Naming engines must not weaken the gate: an analysis WITHOUT per-engine
+# results still blocks on the counts alone.
+[ "$(run_gate v0.9.1 one_malicious)" != "0" ] || \
+  fail "detection without engine detail must still block"
+
 rm -f /tmp/vt_gate_fail
-echo "PASS: VT gate is zero tolerance — every detection blocks on every version"
+echo "PASS: VT gate is zero tolerance and names the engine that fired"