diff --git a/engagements/2026-08-22-audit-core-e2.json b/engagements/2026-08-22-audit-core-e2.json
index c3de190..83021a9 100644
--- a/engagements/2026-08-22-audit-core-e2.json
+++ b/engagements/2026-08-22-audit-core-e2.json
@@ -16,10 +16,10 @@
   "production_approval": "Explicit operator approval of WH-ENG-20260822-AUDIT-E2-01 in the coordinating session on 2026-08-22",
   "approval_class": "live-e2",
   "plane_namespace": "whitehat",
-  "runner_image_digest": "sha256:7febc28e8a828dbc245144a38e5728e0fbf496b594dd7591170b450a1265fb10",
+  "runner_image_digest": "sha256:c2fe39a0185b99be3fc0cb14d2de69772b8e66e20490097c9d11d90cc39719a6",
   "namespace": "whitehat",
   "source": "dedicated pod whitehat/whitehat-e2-audit, labels whitehat.security/plane=true, whitehat.security/target=audit-core, whitehat.security/engagement=WH-ENG-20260822-AUDIT-E2-01, serviceAccount whitehat-runner, automountServiceAccountToken=false",
-  "source_image": "forgejo.coulomb.social/coulomb/audit-core@sha256:7febc28e8a828dbc245144a38e5728e0fbf496b594dd7591170b450a1265fb10",
+  "source_image": "forgejo.coulomb.social/coulomb/audit-core@sha256:c2fe39a0185b99be3fc0cb14d2de69772b8e66e20490097c9d11d90cc39719a6",
   "control_plane_scope": [
     "GET apps/v1 deployment audit-core/audit-core for target revision only",
     "GET v1 service audit-core/audit-core for target identity only",
@@ -36,7 +36,8 @@
   "fixture_ids": [
     "tenant:trial:whitehat-a-20260822", "tenant:trial:whitehat-b-20260822",
     "whitehat-e2-event-a-20260822", "whitehat-e2-event-b-20260822",
-    "whitehat-e2-absent-20260822", "whitehat-e2-correlation-20260822"
+    "whitehat-e2-absent-20260822", "whitehat-e2-forged-b-20260822",
+    "whitehat-e2-correlation-20260822"
   ],
   "credential_lane": "audit-core sender registry through its sanctioned custody owner; no credential value retained",
   "credential_role": "two temporary ordinary tenant-scoped may_read/may_write fixture senders bound to source=whitehat-security",
diff --git a/runners/audit_core_e2.py b/runners/audit_core_e2.py
index bd7df71..1890e10 100644
--- a/runners/audit_core_e2.py
+++ b/runners/audit_core_e2.py
@@ -169,6 +169,20 @@ def equivalent(left: dict, right: dict) -> bool:
     ))
 
 
+def invocation_fixture_ids(args: argparse.Namespace) -> set[str]:
+    """Exact synthetic identifiers the invocation may address or emit."""
+
+    return {
+        args.tenant_a,
+        args.tenant_b,
+        args.event_a,
+        args.event_b,
+        args.absent_event,
+        args.correlation,
+        args.forged_event,
+    }
+
+
 def main() -> None:
     parser = argparse.ArgumentParser()
     parser.add_argument("--base-url", required=True)
@@ -181,6 +195,7 @@ def main() -> None:
     parser.add_argument("--event-a", required=True)
     parser.add_argument("--event-b", required=True)
     parser.add_argument("--absent-event", required=True)
+    parser.add_argument("--forged-event", required=True)
     parser.add_argument("--correlation", required=True)
     parser.add_argument("--occurred-at", required=True,
                         help="fixed RFC3339 fixture time; makes retries idempotent")
@@ -238,7 +253,7 @@ def main() -> None:
                         "outcome": "finding" if reasons else "pass", "reasons": reasons,
                         "observations": {"owner": owner_corr, "attacker": attacker_corr}})
 
-        forged = "whitehat-e2-forged-b-20260821"
+        forged = args.forged_event
         forged_response = client.observation(client.call(
             args.token_a_file, "POST", "/v1/events",
             event(forged, args.tenant_b, args.correlation, args.occurred_at)
diff --git a/tests/test_audit_core_runner.py b/tests/test_audit_core_runner.py
index b1e8cd8..957fad5 100644
--- a/tests/test_audit_core_runner.py
+++ b/tests/test_audit_core_runner.py
@@ -1,4 +1,6 @@
 import importlib.util
+import json
+from argparse import Namespace
 from pathlib import Path
 
 
@@ -43,3 +45,20 @@ def test_post_headers_bind_idempotency_key_to_event_id():
 def test_get_headers_have_no_idempotency_key():
     headers = runner.request_headers("secret", "eng-1", "corr-1", None)
     assert "Idempotency-Key" not in headers
+
+
+def test_invocation_fixture_set_is_declared_by_current_engagement():
+    engagement = json.loads(
+        Path("engagements/2026-08-22-audit-core-e2.json").read_text()
+    )
+    args = Namespace(
+        tenant_a="tenant:trial:whitehat-a-20260822",
+        tenant_b="tenant:trial:whitehat-b-20260822",
+        event_a="whitehat-e2-event-a-20260822",
+        event_b="whitehat-e2-event-b-20260822",
+        absent_event="whitehat-e2-absent-20260822",
+        forged_event="whitehat-e2-forged-b-20260822",
+        correlation="whitehat-e2-correlation-20260822",
+    )
+
+    assert runner.invocation_fixture_ids(args) <= set(engagement["fixture_ids"])