diff --git a/backend/src/cyclone/store.py b/backend/src/cyclone/store.py
index c6f5397..de4396a 100644
--- a/backend/src/cyclone/store.py
+++ b/backend/src/cyclone/store.py
@@ -1297,6 +1297,78 @@ class CycloneStore:
                 # default ``None`` — the UI shows "no match" rather
                 # than crashing.
 
+            # SP7 §5.2: slim per-line projection so the ServiceLinesTable
+            # can show Paid + Adjustments columns without a second fetch.
+            # The 837 side is keyed by ``claim_service_line_number`` (the
+            # 1-based line number from raw_json) since 837 service lines
+            # are not a separate ORM table.
+            from cyclone.db import (
+                LineReconciliation, ServiceLinePayment, CasAdjustment,
+            )
+            slim_lrs = list(
+                s.query(LineReconciliation)
+                .filter(LineReconciliation.claim_id == claim_id)
+                .all()
+            )
+            svc_ids_for_cas = [
+                lr.service_line_payment_id
+                for lr in slim_lrs
+                if lr.service_line_payment_id is not None
+            ]
+            cas_sums_by_svc: dict = {}
+            svc_by_id_slim: dict = {}
+            if svc_ids_for_cas:
+                cas_rows = (
+                    s.query(CasAdjustment.service_line_payment_id, CasAdjustment.amount)
+                    .filter(CasAdjustment.service_line_payment_id.in_(svc_ids_for_cas))
+                    .all()
+                )
+                from collections import defaultdict
+                agg = defaultdict(lambda: Decimal("0"))
+                for svc_id, amount in cas_rows:
+                    agg[svc_id] += Decimal(str(amount))
+                cas_sums_by_svc = {k: str(v) for k, v in agg.items()}
+                for svc in (
+                    s.query(ServiceLinePayment)
+                    .filter(ServiceLinePayment.id.in_(svc_ids_for_cas))
+                    .all()
+                ):
+                    svc_by_id_slim[svc.id] = svc
+
+            slim_by_num: dict = {
+                lr.claim_service_line_number: lr
+                for lr in slim_lrs
+                if lr.claim_service_line_number is not None
+            }
+            line_reconciliation_slim: list = []
+            for sl in detail["serviceLines"]:
+                ln = sl.get("lineNumber")
+                lr = slim_by_num.get(ln)
+                if lr is None:
+                    line_reconciliation_slim.append({
+                        "lineNumber": ln,
+                        "status": "unmatched_837_only",
+                        "paid": None,
+                        "adjustmentsSum": None,
+                    })
+                    continue
+                svc = (
+                    svc_by_id_slim.get(lr.service_line_payment_id)
+                    if lr.service_line_payment_id
+                    else None
+                )
+                line_reconciliation_slim.append({
+                    "lineNumber": ln,
+                    "status": lr.status,
+                    "paid": str(Decimal(str(svc.payment))) if svc else None,
+                    "adjustmentsSum": (
+                        cas_sums_by_svc.get(lr.service_line_payment_id)
+                        if lr.service_line_payment_id
+                        else None
+                    ),
+                })
+            detail["lineReconciliation"] = line_reconciliation_slim
+
             return detail
 
     def all(self) -> list[BatchRecord]:
diff --git a/backend/tests/test_api_claim_detail.py b/backend/tests/test_api_claim_detail.py
index efd139d..640c002 100644
--- a/backend/tests/test_api_claim_detail.py
+++ b/backend/tests/test_api_claim_detail.py
@@ -211,4 +211,26 @@ def test_get_claim_detail_matched_remit_inlines_summary(seeded_store_with_pair):
     assert mr["status"] in {"received", "reconciled"}
     # ISO timestamp must end in Z — the spec contract that lets the
     # UI render the time without a tz suffix shim.
-    assert mr["receivedAt"].endswith("Z"), mr["receivedAt"]
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+    assert mr["receivedAt"].endswith("Z"), mr["receivedAt"]
+
+
+def test_get_claim_detail_includes_line_reconciliation_slim_projection(seeded_store):
+    """SP7 §5.2: claim detail exposes a `lineReconciliation` slim list
+    parallel to `serviceLines`, indexed by line number. The values are
+    strings (Decimals serialized) or nulls when the line is unmatched."""
+    cid = seeded_store.get("/api/claims", headers=JSON).json()["items"][0]["id"]
+    resp = seeded_store.get(f"/api/claims/{cid}")
+    assert resp.status_code == 200, resp.text
+    body = resp.json()
+    assert "lineReconciliation" in body
+    lr_list = body["lineReconciliation"]
+    assert isinstance(lr_list, list)
+    # No 835 was ingested in this fixture, so every line is unmatched
+    # on the 835 side — the default for an unpaired claim.
+    for row in lr_list:
+        assert "lineNumber" in row
+        assert "status" in row
+        assert "paid" in row
+        assert "adjustmentsSum" in row
+    # One entry per service line.
+    assert len(lr_list) == len(body["serviceLines"])
\ No newline at end of file