diff --git a/scripts/publish_test_metrics.py b/scripts/publish_test_metrics.py
index 6b1c52b..3834c90 100644
--- a/scripts/publish_test_metrics.py
+++ b/scripts/publish_test_metrics.py
@@ -6,6 +6,7 @@ from __future__ import annotations
 import json
 import os
 from pathlib import Path
+import urllib.error
 import urllib.request
 import xml.etree.ElementTree as ET
 
@@ -88,6 +89,20 @@ def _load_junit_cases(path: str) -> list[tuple[str, str]]:
     return cases
 
 
+def _dedupe_test_cases(test_cases: list[tuple[str, str]]) -> list[tuple[str, str]]:
+    """Return one sample per Prometheus test/status labelset."""
+
+    seen: set[tuple[str, str]] = set()
+    deduped: list[tuple[str, str]] = []
+    for test_id, status in test_cases:
+        key = (test_id, status)
+        if key in seen:
+            continue
+        seen.add(key)
+        deduped.append(key)
+    return deduped
+
+
 def _load_exit_code(path: str) -> int | None:
     if not path or not os.path.exists(path):
         return None
@@ -108,9 +123,14 @@ def _post_text(url: str, payload: str) -> None:
         method="PUT",
         headers={"Content-Type": "text/plain"},
     )
-    with urllib.request.urlopen(req, timeout=10) as resp:
-        if resp.status >= 400:
-            raise RuntimeError(f"metrics push failed status={resp.status}")
+    try:
+        with urllib.request.urlopen(req, timeout=10) as resp:
+            if resp.status >= 400:
+                raise RuntimeError(f"metrics push failed status={resp.status}")
+    except urllib.error.HTTPError as exc:
+        body = exc.read().decode("utf-8", errors="replace").strip()
+        detail = f": {body}" if body else ""
+        raise RuntimeError(f"metrics push failed status={exc.code}{detail}") from exc
 
 
 def _read_http(url: str) -> str:
@@ -248,7 +268,7 @@ def main() -> int:
 
     coverage = _load_coverage(coverage_path)
     totals = _load_junit(junit_path)
-    test_cases = _load_junit_cases(junit_path)
+    test_cases = _dedupe_test_cases(_load_junit_cases(junit_path))
     test_exit_code = _load_exit_code(test_exit_code_path)
     docs_exit_code = _load_exit_code(docs_exit_code_path)
     source_files_total = _count_source_files(repo_root)