diff --git a/backend/src/cyclone/api.py b/backend/src/cyclone/api.py
index 2c71dc4..875fea4 100644
--- a/backend/src/cyclone/api.py
+++ b/backend/src/cyclone/api.py
@@ -292,12 +292,22 @@ async def parse_835_endpoint(
 
     # Always run the validator; attach the report so the JSON path can
     # surface it and the NDJSON path can fold the counts into the summary.
+    # 835 validation is batch-level, so pass/fail applies uniformly to every
+    # claim payment in the batch (passed=N or 0, failed=0 or N).
     report = validate_835(result, config)
-    passed = 1 if report.passed else 0
-    failed = 1 if not report.passed else 0
+    n = len(result.claims)
+    claim_ids = [c.payer_claim_control_number for c in result.claims]
+    if report.passed:
+        passed, failed, failed_claim_ids = n, 0, []
+    else:
+        passed, failed, failed_claim_ids = 0, n, claim_ids
     result = result.model_copy(update={
         "validation": report,
-        "summary": result.summary.model_copy(update={"passed": passed, "failed": failed}),
+        "summary": result.summary.model_copy(update={
+            "passed": passed,
+            "failed": failed,
+            "failed_claim_ids": failed_claim_ids,
+        }),
     })
 
     if strict:
diff --git a/backend/src/cyclone/cli.py b/backend/src/cyclone/cli.py
index 10124b9..b43f087 100644
--- a/backend/src/cyclone/cli.py
+++ b/backend/src/cyclone/cli.py
@@ -148,17 +148,26 @@ def parse_835(
         raise click.UsageError("No claim payments found in file") from None
 
     # Run validation; populate summary.passed/failed from the report.
+    # 835 validation is batch-level (BPR/CLP/SVC balancing is cross-cutting),
+    # so pass/fail applies uniformly to every claim payment in the batch:
+    # when the batch passes, all N claims "passed" (passed=N, failed=0);
+    # when the batch fails, all N claims "failed" (passed=0, failed=N).
     report = validate_835(result, config)
     if strict:
         promoted = [i.model_copy(update={"severity": "error"}) for i in report.warnings]
         new_errors = report.errors + promoted
         report = report.model_copy(update={"errors": new_errors, "passed": not new_errors})
-    passed = 1 if report.passed else 0
-    failed = 1 if not report.passed else 0
+    n = len(result.claims)
+    claim_ids = [c.payer_claim_control_number for c in result.claims]
+    if report.passed:
+        passed, failed, failed_claim_ids = n, 0, []
+    else:
+        passed, failed, failed_claim_ids = 0, n, claim_ids
     result = result.model_copy(update={"validation": report})
     result.summary = result.summary.model_copy(update={
         "passed": passed,
         "failed": failed,
+        "failed_claim_ids": failed_claim_ids,
         "issues_by_rule": _count_issues(report),
     })
 
diff --git a/backend/tests/test_api_835.py b/backend/tests/test_api_835.py
index 7503a69..571522b 100644
--- a/backend/tests/test_api_835.py
+++ b/backend/tests/test_api_835.py
@@ -41,7 +41,8 @@ def test_parse_835_endpoint_returns_json(client: TestClient):
     assert "claims" in body and len(body["claims"]) == 2
     assert "summary" in body
     assert body["summary"]["total_claims"] == 2
-    assert body["summary"]["passed"] == 1
+    assert body["summary"]["passed"] == 2
+    assert body["summary"]["failed"] == 0
 
 
 # --------------------------------------------------------------------------- #
@@ -79,7 +80,7 @@ def test_parse_835_endpoint_streams_ndjson(client: TestClient):
 
     # Summary numbers match the JSON path.
     assert parsed[7]["data"]["total_claims"] == 2
-    assert parsed[7]["data"]["passed"] == 1
+    assert parsed[7]["data"]["passed"] == 2
 
 
 def test_parse_835_endpoint_streams_ndjson_without_raw_segments(client: TestClient):
@@ -123,7 +124,7 @@ def test_parse_835_endpoint_handles_payer_query_param(client: TestClient):
         assert resp.status_code == 200, (payer, resp.text)
         body = resp.json()
         assert body["summary"]["total_claims"] == 2
-        assert body["summary"]["passed"] == 1
+        assert body["summary"]["passed"] == 2
 
 
 def test_parse_835_endpoint_rejects_unknown_payer(client: TestClient):
diff --git a/backend/tests/test_cli_835.py b/backend/tests/test_cli_835.py
index 2ccc59f..549f6d2 100644
--- a/backend/tests/test_cli_835.py
+++ b/backend/tests/test_cli_835.py
@@ -9,6 +9,7 @@ from cyclone.cli import main
 
 FIXTURE = Path(__file__).parent / "fixtures" / "minimal_835.txt"
 UNBALANCED = Path(__file__).parent / "fixtures" / "unbalanced_835.txt"
+CO_FIXTURE = Path(__file__).parent / "fixtures" / "co_medicaid_835.txt"
 
 
 def test_cli_parse_835_writes_outputs(tmp_path: Path):
@@ -71,3 +72,21 @@ def test_cli_parse_835_generic_payer(tmp_path: Path):
     assert result.exit_code == 0, result.output
     summary = json.loads((tmp_path / "summary.json").read_text())
     assert summary["passed"] == 1
+
+
+def test_cli_parse_835_summary_counts_consistent(tmp_path: Path):
+    """Regression: passed + failed must equal total_claims for any batch size.
+
+    The CO Medicaid fixture has 2 claim payments; if the batch validates
+    cleanly, both must show as passed (passed=2, failed=0). A pre-fix
+    implementation set passed=1 regardless of claim count.
+    """
+    runner = CliRunner()
+    result = runner.invoke(main, ["parse-835", str(CO_FIXTURE), "--output-dir", str(tmp_path)])
+    assert result.exit_code == 0, result.output
+    summary = json.loads((tmp_path / "summary.json").read_text())
+    assert summary["total_claims"] == 2
+    assert summary["passed"] + summary["failed"] == summary["total_claims"]
+    assert summary["passed"] == 2
+    assert summary["failed"] == 0
+    assert summary["failed_claim_ids"] == []