diff --git a/packages/mcp-core/src/tools/catalog/search-events.test.ts b/packages/mcp-core/src/tools/catalog/search-events.test.ts
index 5f6a82246..8aa869ee0 100644
--- a/packages/mcp-core/src/tools/catalog/search-events.test.ts
+++ b/packages/mcp-core/src/tools/catalog/search-events.test.ts
@@ -3419,6 +3419,68 @@ describe("search_events", () => {
     expect(validatedQueries.at(-1)).not.toContain("message:");
   });
 
+  it.each([
+    "environment:production is:unresolved",
+    // Parentheses inside a quoted value are not grouping.
+    'environment:production message:"err (timeout)"',
+  ])(
+    "keeps explicit timestamp bounds the agent moved into an overridden time range: %s",
+    async (filters) => {
+      // The agent moves the bounds into an absolute timeRange, but the explicit
+      // period wins over it, so dropping them would search the whole period.
+      mockGenerateText.mockResolvedValueOnce(
+        mockAIResponse(
+          "errors",
+          filters,
+          ["count()", "count_unique(issue)"],
+          undefined,
+          "-count()",
+          { start: "2025-01-01T00:00:00Z", end: "2025-01-02T00:00:00Z" },
+        ),
+      );
+      const bounds =
+        "timestamp:>=2025-01-01T00:00:00Z timestamp:<2025-01-02T00:00:00Z";
+      const requests: URLSearchParams[] = [];
+      mswServer.use(
+        http.get(
+          "https://sentry.io/api/0/organizations/test-org/events/",
+          ({ request }) => {
+            requests.push(new URL(request.url).searchParams);
+            return HttpResponse.json({ data: [] });
+          },
+        ),
+      );
+
+      await runSearchEvents(
+        {
+          organizationSlug: "test-org",
+          regionUrl: null,
+          projectSlug: null,
+          dataset: "errors",
+          query: `${filters} ${bounds}`,
+          fields: ["count()", "count_unique(issue)"],
+          period: "7d",
+          limit: 10,
+          includeExplanation: false,
+        },
+        {
+          constraints: {
+            organizationSlug: null,
+            regionUrl: null,
+            projectSlug: null,
+          },
+          accessToken: "test-token",
+          userId: "1",
+        },
+        { lockDataset: true },
+      );
+
+      expect(requests).toHaveLength(1);
+      expect(requests[0]!.get("statsPeriod")).toBe("7d");
+      expect(requests[0]!.get("query")).toBe(`${filters} ${bounds}`);
+    },
+  );
+
   it("rejects partial full-text downgrades when a duplicate structured key remains", async () => {
     // Set-based key comparison would miss this: custom remains present after
     // custom:foo is dropped into message full-text.
diff --git a/packages/mcp-core/src/tools/support/search-events/search.ts b/packages/mcp-core/src/tools/support/search-events/search.ts
index 2f070b83f..c13a0e768 100644
--- a/packages/mcp-core/src/tools/support/search-events/search.ts
+++ b/packages/mcp-core/src/tools/support/search-events/search.ts
@@ -351,6 +351,46 @@ function preservesSearchTokens(originalQuery: string, repairedQuery: string) {
   );
 }
 
+const TIME_BOUND_FILTER_PATTERN = /^timestamp:\S/;
+const QUOTED_VALUE_PATTERN = /(["'])(?:\\.|(?!\1).)*\1/g;
+
+/**
+ * Put back explicit `timestamp:` bounds that the agent dropped from a
+ * structured query.
+ *
+ * The agent often moves them into an absolute `timeRange`, but an explicit
+ * `period` wins over that range, so dropping them silently widens the search to
+ * the whole period. Kept bounds only narrow the period, so they are always
+ * safe to send. Grouped or boolean queries are left as they are, because a
+ * bound appended outside its group would change what it means.
+ */
+function restoreDroppedTimeBounds(
+  originalQuery: string,
+  repairedQuery: string,
+): string {
+  const originalTokens = tokenizeSearchQuery(originalQuery);
+  if (
+    originalTokens.some(
+      (token) =>
+        token === "OR" ||
+        token === "AND" ||
+        // Parentheses inside a quoted value, e.g. message:"err (timeout)",
+        // are not grouping.
+        /[()]/.test(token.replace(QUOTED_VALUE_PATTERN, "")),
+    )
+  ) {
+    return repairedQuery;
+  }
+
+  return originalTokens
+    .filter(
+      (token) =>
+        TIME_BOUND_FILTER_PATTERN.test(token) &&
+        !containsSearchToken(repairedQuery, token),
+    )
+    .reduce((query, token) => appendSearchFilter(query, token), repairedQuery);
+}
+
 function choosePreservingRepairedQuery(params: {
   originalQuery: string;
   repairedQuery?: string | null;
@@ -917,13 +957,14 @@ async function executeSearchEvents(
           filter: environmentFilter,
           dataset,
         })
-      : looksLikeSentrySearchSyntax(params.query, dataset) &&
-          isSemanticFilterDowngrade(
+      : looksLikeSentrySearchSyntax(params.query, dataset)
+        ? isSemanticFilterDowngrade(
             params.query ?? "",
             parsed.query || "",
             dataset,
           )
-        ? (params.query ?? "")
+          ? (params.query ?? "")
+          : restoreDroppedTimeBounds(params.query ?? "", parsed.query || "")
         : parsed.query || "";
     sortParam =
       shouldTrustExplicitSearchParams && explicitSort