diff --git a/Services/AnthropicService.cs b/Services/AnthropicService.cs
index f2f8308..a847de9 100644
--- a/Services/AnthropicService.cs
+++ b/Services/AnthropicService.cs
@@ -60,6 +60,7 @@ public class AnthropicService
         int iterations = 0;
         int reviewRound = 0;
         string lastStopReason = "";
+        int promptTrimRetries = 0;
 
         var chain = new ChainRecord
         {
@@ -106,6 +107,23 @@ public class AnthropicService
                 {
                     var errBody = await httpResp.Content.ReadAsStringAsync(workCt);
                     var errMsg = $"API {(int)httpResp.StatusCode}: {errBody}";
+
+                    // Auto-Retry bei "prompt too long" / "exceed context limit": History kürzen und erneut versuchen
+                    if ((int)httpResp.StatusCode == 400 &&
+                        (errBody.Contains("prompt is too long") || errBody.Contains("exceed context limit")) &&
+                        messages.Count > 4 && promptTrimRetries < 5)
+                    {
+                        promptTrimRetries++;
+                        int trimCount = Math.Max(2, messages.Count / 5); // 20% der Messages entfernen
+                        trimCount = TrimMessagesCleanly(messages, trimCount);
+                        if (trimCount > 0)
+                        {
+                            await TryWriteSse(response, "info", new { message = $"History zu lang – {trimCount} ältere Messages entfernt, Retry ({promptTrimRetries}/5)..." }, sseCt);
+                            iterations--; // Iteration nicht zählen, war ja kein echter Versuch
+                            continue; // → nächste while-Iteration mit kürzerer History
+                        }
+                    }
+
                     await _db.SaveMessage(new MessageRecord
                     {
                         ChainId = chainId, Iteration = iterations,
@@ -120,6 +138,7 @@ public class AnthropicService
 
                 var (stopReason, assistantContent, executedTools, streamErrorInfo) = await ProcessStream(response, httpResp, usage, workspace, agentId, workCt, sseCt);
                 lastStopReason = stopReason;
+                promptTrimRetries = 0; // Erfolgreicher API-Call → Retry-Counter resetten
 
                 messages.Add(new { role = "assistant", content = assistantContent });
 
@@ -726,6 +745,20 @@ public class AnthropicService
 
             if (!httpResp.IsSuccessStatusCode)
             {
+                // Auto-Retry bei "prompt too long" in Sub-Agents
+                if ((int)httpResp.StatusCode == 400 &&
+                    (respBody.Contains("prompt is too long") || respBody.Contains("exceed context limit")) &&
+                    messages.Count > 4)
+                {
+                    int trimCount = Math.Max(2, messages.Count / 5);
+                    trimCount = TrimMessagesCleanly(messages, trimCount);
+                    if (trimCount > 0)
+                    {
+                        await TryWriteSse(response, "info", new { message = $"{tag}: History zu lang – {trimCount} Messages entfernt, Retry..." }, sseCt);
+                        iterations--;
+                        continue;
+                    }
+                }
                 return ($"{tag}-Agent API Fehler: {(int)httpResp.StatusCode}: {respBody}", iterations);
             }
 
@@ -931,6 +964,20 @@ public class AnthropicService
 
                 if (!httpResp.IsSuccessStatusCode)
                 {
+                    // Auto-Retry bei "prompt too long" in Non-Streaming
+                    if ((int)httpResp.StatusCode == 400 &&
+                        (respBody.Contains("prompt is too long") || respBody.Contains("exceed context limit")) &&
+                        messages.Count > 4)
+                    {
+                        int trimCount = Math.Max(2, messages.Count / 5);
+                        trimCount = TrimMessagesCleanly(messages, trimCount);
+                        if (trimCount > 0)
+                        {
+                            iterations--;
+                            continue;
+                        }
+                    }
+
                     var errMsg = $"API {(int)httpResp.StatusCode}: {respBody}";
                     await _db.SaveMessage(new MessageRecord
                     {
@@ -1485,6 +1532,50 @@ public class AnthropicService
         payload["tool_choice"] = new { type = effectiveChoice };
     }
 
+    /// <summary>
+    /// Entfernt Messages vom Anfang der Liste, ohne tool_use/tool_result-Paare zu trennen.
+    /// Gibt die tatsächliche Anzahl entfernter Messages zurück.
+    /// </summary>
+    private static int TrimMessagesCleanly(List<object> messages, int targetRemoveCount)
+    {
+        if (targetRemoveCount <= 0 || targetRemoveCount >= messages.Count)
+            return 0;
+
+        int removeCount = targetRemoveCount;
+
+        // Sicherstellen, dass wir nicht mitten in einem tool_use/tool_result-Paar abschneiden
+        while (removeCount < messages.Count - 1)
+        {
+            var firstRemaining = messages[removeCount];
+            var firstRemainingJson = JsonSerializer.Serialize(firstRemaining);
+
+            // Wenn die erste verbleibende Message ein tool_result ist → vorherige auch behalten
+            if (firstRemainingJson.Contains("\"tool_result\""))
+            {
+                removeCount--;
+                if (removeCount <= 0) return 0;
+                continue;
+            }
+
+            // Wenn die letzte entfernte Message ein assistant mit tool_use ist → tool_result auch entfernen
+            var lastRemovedJson = JsonSerializer.Serialize(messages[removeCount - 1]);
+            if (lastRemovedJson.Contains("\"tool_use\"") && lastRemovedJson.Contains("\"assistant\""))
+            {
+                removeCount++;
+                continue;
+            }
+
+            break;
+        }
+
+        if (removeCount > 0 && removeCount < messages.Count)
+        {
+            messages.RemoveRange(0, removeCount);
+            return removeCount;
+        }
+        return 0;
+    }
+
     private HttpClient CreateClient()
     {
         var client = _httpFactory.CreateClient();
diff --git a/wwwroot/js/chat.js b/wwwroot/js/chat.js
index c98eda6..390ce1b 100644
--- a/wwwroot/js/chat.js
+++ b/wwwroot/js/chat.js
@@ -107,6 +107,10 @@ function handleStreamEvent(eventType, data) {
       finalizeReviewBubble('done', data, 'finalizer');
       break;
 
+    case 'info':
+      addWarningBubble(data.message, true);
+      break;
+
     case 'error':
       endStreamBubble();
       addErrorBubble(data.error, true);