diff --git a/CalenTask/Support/NaturalDateParser.swift b/CalenTask/Support/NaturalDateParser.swift
index 4d6aeca..87aadf8 100644
--- a/CalenTask/Support/NaturalDateParser.swift
+++ b/CalenTask/Support/NaturalDateParser.swift
@@ -12,7 +12,12 @@ enum NaturalDateParser {
         let cleanedText: String
     }
 
+    /// #64 — oltre questa lunghezza il testo non è una frase di cattura: niente
+    /// regex né data detector (evita costi superlineari su input enormi).
+    static let maxInputLength = 500
+
     static func parse(_ text: String, now: Date = .now, calendar: Calendar = .current) -> Match? {
+        guard text.count <= maxInputLength else { return nil }
         if let italian = parseItalian(text, now: now, calendar: calendar) {
             return italian
         }
diff --git a/CalenTaskTests/CalenTaskTests.swift b/CalenTaskTests/CalenTaskTests.swift
index 11124a3..d698d80 100644
--- a/CalenTaskTests/CalenTaskTests.swift
+++ b/CalenTaskTests/CalenTaskTests.swift
@@ -506,6 +506,11 @@ struct DomainModelTests {
         #expect(tagCount == 2)  // "montaggio" survives as a workspace tag
     }
 
+    @Test func naturalDateParserIgnoraTestiTroppoLunghi() {
+        let long = "domani " + String(repeating: "a", count: NaturalDateParser.maxInputLength)
+        #expect(NaturalDateParser.parse(long) == nil)
+    }
+
     @Test func italianRelativeDateParsing() throws {
         let calendar = Calendar.current
         let now = calendar.date(from: DateComponents(year: 2026, month: 6, day: 10, hour: 10))!