diff --git a/backend/app/analysis_run_start.py b/backend/app/analysis_run_start.py
index 90c2ffbde..80021a527 100644
--- a/backend/app/analysis_run_start.py
+++ b/backend/app/analysis_run_start.py
@@ -733,9 +733,24 @@ async def _deliver_lineage_reconstruction(
             f"channels ({', '.join(sorted(active_channels))}). Run "
             "scripts/estimate_channel_weights.py, then start this run again.",
         )
-    edges = lineage_edge_specs(
-        records_from_source_posts(rows), llm=adjudication_client, weights=weights
-    )
+    try:
+        edges = lineage_edge_specs(
+            records_from_source_posts(rows), llm=adjudication_client, weights=weights
+        )
+    except (HttpClientError, OSError, ValueError, TypeError) as exc:
+        # Only the llm channel talks to a provider mid-reconstruction; a
+        # deterministic run hitting this would be a code bug worth the
+        # crash. The enclosing transaction rolls back, so no partial
+        # graph persists (issue #289 RED 4/6) and the run stays
+        # startable once the provider recovers.
+        if "llm" not in active_channels:
+            raise
+        raise AnalysisRunStartError(
+            503,
+            "The adjudication provider failed mid-reconstruction; nothing "
+            "was persisted. Check the contextual-orchestrator transport, "
+            "then start this run again.",
+        ) from exc
     digest = reconstruction_result_digest(edges)
     finished = datetime.now(timezone.utc)
     if finished < now:
diff --git a/tests/test_analysis_run_start.py b/tests/test_analysis_run_start.py
index c2b1b6065..038ed0228 100644
--- a/tests/test_analysis_run_start.py
+++ b/tests/test_analysis_run_start.py
@@ -171,3 +171,91 @@ def test_running_restart_conflicts_and_succeeded_replay_is_documented() -> None:
     )
     assert running.status_code == 409
     assert "Pending" in running.detail
+
+
+def test_provider_failure_mid_reconstruction_fails_closed_without_partial_graph() -> None:
+    """Issue #289 RED 4/6: an adjudication provider error during an
+    llm-inclusive delivery becomes an actionable 503 -- never a fabricated
+    score, never a partially persisted graph (no insert runs).
+    """
+    import asyncio
+
+    from backend.app.analysis_run_start import _deliver_lineage_reconstruction
+    from lineageweave.http_client import HttpClientError
+
+    class _FailingJudge:
+        available = True
+
+        def judge(self, candidate_label: str, record_label: str) -> float:
+            raise HttpClientError("HTTP 500 from orchestrator")
+
+    class _Conn:
+        def __init__(self) -> None:
+            self.executed: list[str] = []
+
+        def transaction(self):
+            class _Tx:
+                async def __aenter__(self):
+                    return self
+
+                async def __aexit__(self, exc_type, exc, traceback) -> bool:
+                    return False
+
+            return _Tx()
+
+        async def fetch(self, query: str, *args: object):
+            if "lineage_channel_weight" in query:
+                return [
+                    {"channel_set_code": "channel_set_with_llm", "channel_code": "temporal", "weight_value": 0.4},
+                    {"channel_set_code": "channel_set_with_llm", "channel_code": "secondary_key", "weight_value": 0.1},
+                    {"channel_set_code": "channel_set_with_llm", "channel_code": "text", "weight_value": 0.1},
+                    {"channel_set_code": "channel_set_with_llm", "channel_code": "llm", "weight_value": 0.4},
+                ]
+            if "analysis_source_snapshot_member" in query:
+                return [
+                    {
+                        "post_id": "aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa",
+                        "post_title": "First post in thread",
+                        "created_at": datetime(2026, 1, 1),
+                        "visibility_code": "public",
+                        "corporate_entity_id": "corp",
+                        "process_unit_id": "pu",
+                        "thread_group_key": "T-100",
+                        "secondary_grouping_key": "",
+                    },
+                    {
+                        "post_id": "bbbbbbbb-bbbb-bbbb-bbbb-bbbbbbbbbbbb",
+                        "post_title": "Second post in thread",
+                        "created_at": datetime(2026, 1, 2),
+                        "visibility_code": "public",
+                        "corporate_entity_id": "corp",
+                        "process_unit_id": "pu",
+                        "thread_group_key": "T-100",
+                        "secondary_grouping_key": "",
+                    },
+                ]
+            raise AssertionError(f"unexpected query: {query[:80]}")
+
+        async def execute(self, query: str, *args: object) -> str:
+            self.executed.append(query)
+            return "OK"
+
+    conn = _Conn()
+    locked = {
+        "analysis_source_snapshot_id": "snapshot-1",
+        "corporate_entity_id": "corp",
+        "knowledge_cutoff": datetime(2026, 2, 1, tzinfo=timezone.utc),
+    }
+    with pytest.raises(AnalysisRunStartError) as raised:
+        asyncio.run(
+            _deliver_lineage_reconstruction(
+                conn,
+                analysis_run_id="00000000-0000-0000-0000-000000000009",
+                locked=locked,
+                affiliated_entity_ids=[],
+                adjudication_client=_FailingJudge(),
+            )
+        )
+    assert raised.value.status_code == 503
+    assert "start this run again" in raised.value.detail
+    assert conn.executed == []