Harden private search fallback and freshness handling

platform/web-search/web_search_mcp.py

@@ -1614,6 +1614,7 @@ def web_search(arguments: dict[str, Any]) -> dict[str, Any]:
     )
     results: list[dict[str, Any]] = []
     backend_warning = None
+    freshness_applied = freshness == "any"
     if backend in {"github", "huggingface"}:
         try:
             results.extend(specialized_search(backend, query, limit))
@@ -1626,6 +1627,14 @@ def web_search(arguments: dict[str, Any]) -> dict[str, Any]:
             results.extend(parse_search_xml(payload, limit))
     else:
         discovered, discovery_warnings = general_discovery(scoped_query, limit, freshness)
+        freshness_applied = freshness == "any" or bool(discovered)
+        if not discovered and freshness != "any":
+            discovered, relaxed_warnings = general_discovery(scoped_query, limit, "any")
+            discovery_warnings.extend(relaxed_warnings)
+            if discovered:
+                discovery_warnings.append(
+                    f"No results survived freshness={freshness}; returned unfiltered discovery results. Verify publication dates before claiming recency."
+                )
         results.extend(discovered)
         if discovery_warnings:
             backend_warning = "; ".join(discovery_warnings)
@@ -1636,6 +1645,7 @@ def web_search(arguments: dict[str, Any]) -> dict[str, Any]:
         "query": query,
         "backend_used": backend,
         "freshness": freshness,
+        "freshness_applied": freshness_applied,
         "domain_filters": {"include": includes, "exclude": excludes},
         "result_semantics": (
             "api_verified evidence comes from the named primary API. preview_unverified is "