diff --git a/src/benchmark_radar/attention.py b/src/benchmark_radar/attention.py
index 67cbd294..1244b5e0 100644
--- a/src/benchmark_radar/attention.py
+++ b/src/benchmark_radar/attention.py
@@ -2,6 +2,7 @@
 
 from copy import deepcopy
 from datetime import UTC, datetime
+from math import isfinite
 from typing import Any
 from urllib.parse import urlsplit
 
@@ -12,6 +13,24 @@
 LEGACY_HACKER_NEWS_PRODUCER = "benchmark-social-signal"
 
 
+def _metrics(values: Any) -> dict[str, float]:
+    # Public feeds must not turn booleans into measurements or persist Infinity,
+    # which cannot be read as a JSON number by downstream consumers.
+    if not isinstance(values, dict):
+        return {}
+    normalized = {}
+    for key, value in values.items():
+        if type(value) not in (int, float):
+            continue
+        try:
+            numeric = float(value)
+        except OverflowError:
+            continue
+        if isfinite(numeric) and numeric >= 0:
+            normalized[str(key)] = numeric
+    return normalized
+
+
 def _date(value: str | None, *, fallback: datetime) -> datetime:
     if not value:
         return fallback
@@ -47,11 +66,7 @@ def _supporting_observations(
                 "source_id": source_id,
                 "url": url,
                 "published_at": str(published_at),
-                "metrics": {
-                    str(key): float(metric)
-                    for key, metric in (value.get("metrics") or {}).items()
-                    if isinstance(metric, int | float) and metric >= 0
-                },
+                "metrics": _metrics(value.get("metrics")),
                 **(
                     {"primary_artifact_url": primary}
                     if (primary := _http_url(value.get("primary_artifact_url")))
@@ -103,11 +118,7 @@ def _normalize_feed(
             event_kind=str(raw.get("event_kind") or "discussed"),
             authors=[str(author) for author in raw.get("authors") or []],
             primary_artifact_url=_http_url(raw.get("primary_artifact_url")),
-            metrics={
-                str(key): float(value)
-                for key, value in (raw.get("metrics") or {}).items()
-                if isinstance(value, int | float) and value >= 0
-            },
+            metrics=_metrics(raw.get("metrics")),
             categories=sorted(
                 {str(category) for category in raw.get("categories") or [] if category}
             ),
@@ -167,11 +178,7 @@ def _restore_previous(
                     event_kind=str(raw.get("event_kind") or "discussed"),
                     authors=[str(author) for author in raw.get("authors") or []],
                     primary_artifact_url=_http_url(raw.get("primary_artifact_url")),
-                    metrics={
-                        str(key): float(value)
-                        for key, value in (raw.get("metrics") or {}).items()
-                        if isinstance(value, int | float) and value >= 0
-                    },
+                    metrics=_metrics(raw.get("metrics")),
                     categories=[str(value) for value in raw.get("categories") or []],
                     rationale=[str(value) for value in raw.get("rationale") or []],
                     supporting_observations=_supporting_observations(
diff --git a/tests/test_attention.py b/tests/test_attention.py
index 5827f9b8..c6e4b58e 100644
--- a/tests/test_attention.py
+++ b/tests/test_attention.py
@@ -1,3 +1,4 @@
+import json
 from datetime import UTC, datetime
 
 from benchmark_radar.attention import fetch_attention_feeds
@@ -165,3 +166,58 @@ def test_first_observed_time_survives_reingestion(monkeypatch):
     )
 
     assert observations[0].observed_at.isoformat() == first
+
+
+def test_feed_metrics_preserve_measured_zero_but_cannot_emit_non_json_numbers(monkeypatch):
+    # A producer's overflowing JSON number became Infinity in the public snapshot;
+    # booleans also acquired a fabricated numeric measurement of one.
+    now = datetime(2026, 7, 27, 12, tzinfo=UTC)
+    invalid = {
+        "points": float("inf"),
+        "flag": True,
+        "zero": 0,
+        "valid": 2.5,
+        "nan": float("nan"),
+        "huge": 10**400,
+        "negative": -1,
+    }
+    raw = local_observation(now)
+    raw["metrics"] = invalid
+    raw["supporting_observations"] = [
+        {
+            "source_id": "2",
+            "url": "https://news.ycombinator.com/item?id=2",
+            "published_at": raw["published_at"],
+            "metrics": invalid,
+        }
+    ]
+    payload = {"schema_version": 1, "producer": "fixture", "observations": [raw], "health": []}
+    monkeypatch.setattr("benchmark_radar.attention.get_json", lambda url: payload)
+    observations, health, _, _ = fetch_attention_feeds(
+        {"feeds": [{"url": "https://example.test/feed.json"}]}, observed_at=now
+    )
+    assert health[0].ok
+    assert observations[0].metrics == {"zero": 0.0, "valid": 2.5}
+    assert observations[0].supporting_observations[0]["metrics"] == observations[0].metrics
+    json.dumps(observations[0].to_dict(), allow_nan=False)
+
+
+def test_failed_collector_sanitizes_metrics_from_legacy_observations(monkeypatch):
+    now = datetime(2026, 7, 27, 12, tzinfo=UTC)
+    monkeypatch.setattr(
+        "benchmark_radar.attention.collect_hacker_news",
+        lambda *args, **kwargs: ([], {"ok": False, "error": "offline"}),
+    )
+    previous = {
+        **local_observation(now),
+        "producer": "benchmark-social-signal",
+        "observation_id": "benchmark-social-signal:hacker-news:1",
+        "observed_at": now.isoformat(),
+        "metrics": {"points": float("inf"), "flag": True, "zero": 0},
+    }
+    restored, health, _, _ = fetch_attention_feeds(
+        LOCAL_CONFIG, observed_at=now, previous_observations=[previous]
+    )
+    assert not health[0].ok
+    assert restored[0].metrics == {"zero": 0.0}
+    json.dumps(restored[0].to_dict(), allow_nan=False)