diff --git a/docs/hermes_full_handoff_acceptance.md b/docs/hermes_full_handoff_acceptance.md
index 23efe79f..56a44b1d 100644
--- a/docs/hermes_full_handoff_acceptance.md
+++ b/docs/hermes_full_handoff_acceptance.md
@@ -136,7 +136,12 @@ unknown or reconciling state is not healthy.
 `release.exact-lineage-is-running` atomically binds:
 
 - fixed remote `main` SHA and local `origin/main`;
-- open draft PR #19, base `main`, existing feature ref, and exact reviewed head;
+- merged PR #19 — `state=closed` with `merged=true`, base `main`, the existing
+  feature ref, and the exact reviewed head — with that head additionally proven
+  an ancestor of the release `main` by `git merge-base --is-ancestor`. A PR
+  that is still open, closed without merging, or carrying a different head is a
+  `FAIL`: after integration, only the merged terminal state proves the reviewed
+  code is what runs;
 - the exact `:git-<source-SHA>-build-<n>@sha256:<digest>` image identity,
   with the source SHA equal to the release `main` SHA;
 - current Deployment generation and revision;
diff --git a/scripts/ops/hermes_handoff_checks_delivery.py b/scripts/ops/hermes_handoff_checks_delivery.py
index 102f93e4..c2388647 100644
--- a/scripts/ops/hermes_handoff_checks_delivery.py
+++ b/scripts/ops/hermes_handoff_checks_delivery.py
@@ -225,7 +225,7 @@ def _release_lineage(targets: Targets) -> CheckSpec:
     )
     return check(
         "release.exact-lineage-is-running",
-        "Remote main, reviewed PR, image, build, Flux, and running revision are identical",
+        "Remote main, merged reviewed PR, image, build, Flux, and running revision agree",
         "release",
         "release_lineage",
         [
@@ -251,6 +251,15 @@ def _release_lineage(targets: Targets) -> CheckSpec:
                 "rev-parse",
                 f"{targets.remote}/main",
             ),
+            step(
+                "merge-ancestry",
+                OPERATOR,
+                "git",
+                "merge-base",
+                "--is-ancestor",
+                targets.reviewed_head_sha,
+                f"{targets.remote}/main",
+            ),
             step(
                 "deployment",
                 OPERATOR,
diff --git a/scripts/ops/hermes_handoff_evaluators.py b/scripts/ops/hermes_handoff_evaluators.py
index ea0a21b8..6216e37f 100644
--- a/scripts/ops/hermes_handoff_evaluators.py
+++ b/scripts/ops/hermes_handoff_evaluators.py
@@ -420,11 +420,9 @@ def evaluate_release_lineage(spec: CheckSpec, outcomes: dict[str, Outcome]) -> E
         return pr
     fields = {
         "number": expected["pr_number"],
-        "state": "open",
-        "draft": True,
-        "merged": False,
+        "state": "closed",
+        "merged": True,
         "base.ref": "main",
-        "base.sha": main_sha,
         "head.ref": expected["head_ref"],
         "head.sha": head_sha,
     }
@@ -437,6 +435,10 @@ def evaluate_release_lineage(spec: CheckSpec, outcomes: dict[str, Outcome]) -> E
             return Evaluation(FAIL, f"reviewed PR {path} does not match", {path: actual})
     if outcomes["build-source"].stdout.strip() != build_sha:
         return Evaluation(FAIL, "build source SHA does not match the fixed release build SHA")
+    ancestry = outcomes["merge-ancestry"]
+    if not ancestry.ok:
+        status = FAIL if ancestry.returncode == 1 else NOT_RUN
+        return Evaluation(status, "reviewed head is not a proven ancestor of remote main")
     deployment = outcomes["deployment"].stdout.strip().split("\t")
     if len(deployment) != 6:
         return Evaluation(NOT_RUN, "Deployment projection is malformed")
diff --git a/scripts/ops/hermes_handoff_run.py b/scripts/ops/hermes_handoff_run.py
index 45459dc8..2d6eae0e 100644
--- a/scripts/ops/hermes_handoff_run.py
+++ b/scripts/ops/hermes_handoff_run.py
@@ -134,7 +134,7 @@ def validate_targets(targets: Targets) -> list[str]:
         or targets.reviewed_head_ref != "feature/hermes-full-handoff-acceptance"
     ):
         problems.append(
-            "reviewed PR identity must remain fixed to draft PR #19 and its existing branch"
+            "reviewed PR identity must remain fixed to PR #19 and its existing branch"
         )
     for label, value in (
         ("baseline commit", targets.baseline_commit),
diff --git a/testing/tests/test_hermes_handoff_evaluators.py b/testing/tests/test_hermes_handoff_evaluators.py
index 4de16c7e..4df1380f 100644
--- a/testing/tests/test_hermes_handoff_evaluators.py
+++ b/testing/tests/test_hermes_handoff_evaluators.py
@@ -341,6 +341,7 @@ def lineage_spec():
         "remote-main",
         "reviewed-pr",
         "build-source",
+        "merge-ancestry",
         "deployment",
         "pods",
         "replicasets",
@@ -364,16 +365,18 @@ def lineage_spec():
 def lineage_outcomes():
     pull = {
         "number": 19,
-        "state": "open",
-        "draft": True,
-        "merged": False,
-        "base": {"ref": "main", "sha": MAIN},
+        "state": "closed",
+        "draft": False,
+        "merged": True,
+        # The recorded base SHA is the pre-merge base, not the current main.
+        "base": {"ref": "main", "sha": "3" * 40},
         "head": {"ref": "feature/hermes-full-handoff-acceptance", "sha": HEAD},
     }
     return {
         "remote-main": outcome(stdout=f"{MAIN}\trefs/heads/main\n"),
         "reviewed-pr": outcome(stdout=json.dumps(pull)),
         "build-source": outcome(stdout=BUILD),
+        "merge-ancestry": outcome(),
         "deployment": outcome(stdout=f"5\t5\t2\t2\t7\t{IMAGE}"),
         "replicasets": outcome(
             stdout=f"rs-old\t6\t0\t0\t{IMAGE}\told\nrs-live\t7\t2\t2\t{IMAGE}\thash7\n"
@@ -392,6 +395,34 @@ def test_release_lineage_atomically_binds_every_release_identity() -> None:
     assert evaluate(lineage_spec(), lineage_outcomes()).status == model.PASS
 
 
+@pytest.mark.parametrize(
+    "patch",
+    [
+        {"state": "open", "draft": True, "merged": False},
+        {"state": "closed", "merged": False},
+        {"head": {"ref": "feature/hermes-full-handoff-acceptance", "sha": "9" * 40}},
+    ],
+    ids=["still-open-draft", "closed-without-merging", "wrong-head-sha"],
+)
+def test_release_lineage_accepts_only_the_merged_terminal_pr_state(patch) -> None:
+    """After integration, only the merged PR proves the reviewed code runs."""
+    outcomes = lineage_outcomes()
+    pull = {**json.loads(outcomes["reviewed-pr"].stdout), **patch}
+    outcomes["reviewed-pr"] = outcome(stdout=json.dumps(pull))
+
+    assert evaluate(lineage_spec(), outcomes).status == model.FAIL
+
+
+def test_release_lineage_requires_the_merged_head_to_be_an_ancestor_of_main() -> None:
+    not_ancestor = lineage_outcomes()
+    not_ancestor["merge-ancestry"] = outcome(returncode=1)
+    assert evaluate(lineage_spec(), not_ancestor).status == model.FAIL
+
+    undecidable = lineage_outcomes()
+    undecidable["merge-ancestry"] = outcome(returncode=128)
+    assert evaluate(lineage_spec(), undecidable).status == model.NOT_RUN
+
+
 @pytest.mark.parametrize(
     ("key", "bad"),
     [