refactor: AnthropicService partial-class Aufteilung + ToolPayloadOptions + Non-Streaming Deduplizierung

- AnthropicService.cs (337 Zeilen): Felder, Konstruktor, Setters, Utilities
- AnthropicService.Streaming.cs (750 Zeilen): StreamChat, ProcessStream, SSE-Parsing
- AnthropicService.Agents.cs (680 Zeilen): RunAgentChat, ChatNonStreaming, Review/Preparer/Finalizer
- AnthropicService.Cli.cs (530 Zeilen): StreamChatViaCli, MCP-Config, CLI-Helpers
- AddToolsToPayload: 12 Bool-Parameter → ToolPayloadOptions Record
- RunAgentChat + ChatNonStreaming → gemeinsame RunNonStreamingToolLoop-Methode

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Services/AnthropicService.Agents.cs

@@ -0,0 +1,680 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Gott.Models;
+using Microsoft.AspNetCore.Http;
+
+namespace Gott.Services;
+
+public partial class AnthropicService
+{
+    // ── Preparer-Agent Logik ──
+
+    public class PreparerResult
+    {
+        public bool ShouldForward { get; set; }
+        public string ForwardedPrompt { get; set; }
+        public string ResponseText { get; set; }
+        public int IterationCount { get; set; }
+    }
+
+    /// <summary>
+    /// Führt den Preparer-Agent aus. Der Preparer bekommt die User-Nachricht und die bisherige Konversation.
+    /// Antwortet er mit [FORWARD] → der Text nach [FORWARD] wird an den Session-Agent weitergegeben.
+    /// Sonst → seine Antwort wird als Rückfrage an den User gestreamt.
+    /// </summary>
+    public async Task<PreparerResult> RunPreparer(
+        HttpResponse response,
+        SubAgentContext preparer,
+        List<object> historyMessages,
+        string chainId,
+        string workspace,
+        string sessionId,
+        string apiToken,
+        CancellationToken cancellationToken)
+    {
+        // Preparer läuft VOR dem Worker und nutzt den Request-CancellationToken direkt.
+        // Bei Client-Disconnect wird der Preparer abgebrochen (kein Sinn weiterzumachen,
+        // da der Worker noch nicht gestartet hat).
+        cancellationToken.ThrowIfCancellationRequested();
+
+        await SseHelper.TryWriteSse(response, "preparer_start", new
+        {
+            agentId = preparer.AgentId,
+            agentName = preparer.Agent?.Name ?? "Vorbereiter-Agent"
+        }, cancellationToken);
+
+        // Preparer bekommt die History als Kontext
+        var preparerMessages = new List<object>(historyMessages);
+
+        var usage = new TokenUsage();
+        string text;
+        int iterations;
+
+        if (!string.IsNullOrEmpty(preparer.Provider) && _openAiService != null)
+        {
+            // OpenAI-kompatibler Preparer
+            var subCtx = BuildSubAgentChatContext(preparer, chainId, sessionId, apiToken);
+            text = await _openAiService.ChatNonStreaming(subCtx, preparerMessages);
+            iterations = 1;
+        }
+        else
+        {
+            (text, iterations) = await RunAgentChat(
+                response, preparer.ModelId, preparer.SystemPrompt, preparer.AgentId,
+                preparer.Workspace, preparer.UseMemory, preparer.WebSearchVersion,
+                preparer.ToolChoice, preparerMessages, chainId, sessionId, apiToken, usage,
+                0, "preparer", preparer.Agent?.Name ?? "Vorbereiter-Agent",
+                cancellationToken, cancellationToken);
+        }
+
+        var result = new PreparerResult { IterationCount = iterations, ResponseText = text };
+
+        // Logik: Standardmäßig wird IMMER weitergeleitet.
+        // Nur wenn der Preparer explizit [QUESTION] nutzt, wird gestoppt (= Rückfrage an User).
+        // [FORWARD] wird weiterhin erkannt und entfernt, ist aber nicht mehr zwingend nötig.
+        if (!string.IsNullOrEmpty(text) && text.Contains("[QUESTION]"))
+        {
+            // Explizite Rückfrage an User
+            var questionText = text.Replace("[QUESTION]", "").Trim();
+            result.ShouldForward = false;
+            result.ResponseText = questionText;
+
+            await SseHelper.TryWriteSse(response, "preparer_done", new
+            {
+                agentName = preparer.Agent?.Name ?? "Vorbereiter-Agent",
+                forwarded = false,
+                responseText = questionText
+            }, cancellationToken);
+        }
+        else
+        {
+            // Weiterleitung (Standard): [FORWARD]-Tag entfernen falls vorhanden
+            var forwardedText = text ?? "";
+            if (forwardedText.Contains("[FORWARD]"))
+            {
+                var idx = forwardedText.IndexOf("[FORWARD]");
+                forwardedText = forwardedText.Substring(idx + "[FORWARD]".Length).Trim();
+            }
+
+            result.ShouldForward = true;
+            result.ForwardedPrompt = forwardedText;
+
+            await SseHelper.TryWriteSse(response, "preparer_done", new
+            {
+                agentName = preparer.Agent?.Name ?? "Vorbereiter-Agent",
+                forwarded = true
+            }, cancellationToken);
+        }
+
+        return result;
+    }
+
+    // ── Review-Agent Logik ──
+
+    private class ReviewResult
+    {
+        public bool HasFeedback { get; set; }
+        public string Feedback { get; set; }
+        public int ReviewIterationCount { get; set; }
+    }
+
+    /// <summary>
+    /// Führt den Review-Agent aus. Der Review-Agent bekommt die Text-Konversation
+    /// und kann Tools nutzen (z.B. read_file um die Arbeit zu prüfen).
+    /// Default = Approved. Nur bei explizitem [FEEDBACK]-Tag wird Feedback an den Worker zurückgegeben.
+    /// reviewRound = aktuelle Runde (0-basiert), wird vom Caller hochgezählt.
+    /// </summary>
+    private async Task<ReviewResult> RunReview(
+        HttpResponse response,
+        SubAgentContext review,
+        List<object> workerMessages,
+        string chainId,
+        string workspace,
+        string sessionId,
+        string apiToken,
+        TokenUsage usage,
+        int baseIterations,
+        int reviewRound,
+        CancellationToken workCt,
+        CancellationToken sseCt)
+    {
+        await SseHelper.TryWriteSse(response, "review_start", new
+        {
+            agentId = review.AgentId,
+            agentName = review.Agent?.Name ?? "Review-Agent",
+            round = reviewRound
+        }, sseCt);
+
+        // Review-Agent bekommt die Worker-Konversation als Kontext
+        var reviewMessages = BuildReviewMessages(workerMessages);
+
+        string text;
+        int iterations;
+
+        if (!string.IsNullOrEmpty(review.Provider) && _openAiService != null)
+        {
+            // OpenAI-kompatibler Reviewer
+            var subCtx = BuildSubAgentChatContext(review, chainId, sessionId, apiToken);
+            text = await _openAiService.ChatNonStreaming(subCtx, reviewMessages);
+            iterations = 1;
+        }
+        else
+        {
+            (text, iterations) = await RunAgentChat(
+                response, review.ModelId, review.SystemPrompt, review.AgentId,
+                review.Workspace, review.UseMemory, review.WebSearchVersion,
+                review.ToolChoice, reviewMessages, chainId, sessionId, apiToken, usage,
+                baseIterations, "review", review.Agent?.Name ?? "Review-Agent",
+                workCt, sseCt);
+        }
+
+        var result = new ReviewResult { ReviewIterationCount = iterations };
+
+        if (!string.IsNullOrEmpty(text) && text.Contains("[FEEDBACK]"))
+        {
+            var feedbackText = text.Substring(text.IndexOf("[FEEDBACK]") + "[FEEDBACK]".Length).Trim();
+            result.HasFeedback = true;
+            result.Feedback = $"[Review-Feedback, Runde {reviewRound + 1}]: {feedbackText}";
+        }
+
+        await SseHelper.TryWriteSse(response, "review_done", new
+        {
+            agentName = review.Agent?.Name ?? "Review-Agent",
+            round = reviewRound,
+            hasFeedback = result.HasFeedback
+        }, sseCt);
+
+        return result;
+    }
+
+    /// <summary>
+    /// Führt den Finalizer-Agent aus. Wird einmal nach der Review-Phase (oder direkt nach dem Worker) aufgerufen.
+    /// Der Finalizer kann Tools nutzen, gibt aber kein Feedback an den Worker zurück.
+    /// </summary>
+    private async Task<int> RunFinalizer(
+        HttpResponse response,
+        SubAgentContext finalizer,
+        List<object> workerMessages,
+        string chainId,
+        string workspace,
+        string sessionId,
+        string apiToken,
+        TokenUsage usage,
+        int baseIterations,
+        CancellationToken workCt,
+        CancellationToken sseCt)
+    {
+        await SseHelper.TryWriteSse(response, "finalizer_start", new
+        {
+            agentId = finalizer.AgentId,
+            agentName = finalizer.Agent?.Name ?? "Finalizer-Agent"
+        }, sseCt);
+
+        // Finalizer bekommt die Konversation als Kontext (gleiche Methode wie Review)
+        var finalizerMessages = BuildReviewMessages(workerMessages);
+
+        string text;
+        int iterations;
+
+        if (!string.IsNullOrEmpty(finalizer.Provider) && _openAiService != null)
+        {
+            var subCtx = BuildSubAgentChatContext(finalizer, chainId, sessionId, apiToken);
+            text = await _openAiService.ChatNonStreaming(subCtx, finalizerMessages);
+            iterations = 1;
+        }
+        else
+        {
+            (text, iterations) = await RunAgentChat(
+                response, finalizer.ModelId, finalizer.SystemPrompt, finalizer.AgentId,
+                finalizer.Workspace, finalizer.UseMemory, finalizer.WebSearchVersion,
+                finalizer.ToolChoice, finalizerMessages, chainId, sessionId, apiToken, usage,
+                baseIterations, "finalizer", finalizer.Agent?.Name ?? "Finalizer-Agent",
+                workCt, sseCt);
+        }
+
+        await SseHelper.TryWriteSse(response, "finalizer_done", new
+        {
+            agentName = finalizer.Agent?.Name ?? "Finalizer-Agent"
+        }, sseCt);
+
+        return iterations;
+    }
+
+    /// <summary>
+    /// Baut die Messages für den Review-Agent auf.
+    /// Der Review-Agent bekommt die komplette Worker-Konversation als eine User-Message.
+    /// </summary>
+    private List<object> BuildReviewMessages(List<object> workerMessages)
+    {
+        // Nur die Text-Konversation extrahieren – Tool-Calls und Tool-Results weglassen.
+        // Der Review/Finalizer-Agent hat eigene Tools und kann bei Bedarf selbst Dateien lesen.
+        // Aufeinanderfolgende Messages gleicher Rolle werden zusammengeführt,
+        // da die Anthropic API abwechselnde user/assistant-Rollen erfordert.
+        var messages = new List<object>();
+        string lastRole = null;
+        var currentParts = new List<string>();
+
+        foreach (var msg in workerMessages)
+        {
+            var json = JsonSerializer.Serialize(msg);
+            var el = JsonSerializer.Deserialize<JsonElement>(json);
+
+            if (!el.TryGetProperty("role", out var role)) continue;
+            var roleStr = role.GetString() ?? "";
+
+            if (!el.TryGetProperty("content", out var content)) continue;
+
+            string textContent = null;
+
+            if (content.ValueKind == JsonValueKind.String)
+            {
+                textContent = content.GetString();
+            }
+            else if (content.ValueKind == JsonValueKind.Array)
+            {
+                var parts = new List<string>();
+                foreach (var block in content.EnumerateArray())
+                {
+                    var blockType = block.TryGetProperty("type", out var bt) ? bt.GetString() ?? "" : "";
+                    if (blockType == "text" && block.TryGetProperty("text", out var txt))
+                        parts.Add(txt.GetString() ?? "");
+                }
+                if (parts.Count > 0)
+                    textContent = string.Join("\n", parts);
+            }
+
+            if (string.IsNullOrEmpty(textContent)) continue;
+
+            if (roleStr == lastRole)
+            {
+                // Gleiche Rolle → Text anhängen
+                currentParts.Add(textContent);
+            }
+            else
+            {
+                // Rolle wechselt → vorherige Message abschließen
+                if (lastRole != null && currentParts.Count > 0)
+                {
+                    messages.Add(new
+                    {
+                        role = lastRole,
+                        content = string.Join("\n\n", currentParts)
+                    });
+                }
+                lastRole = roleStr;
+                currentParts = new List<string> { textContent };
+            }
+        }
+
+        // Letzte Message abschließen
+        if (lastRole != null && currentParts.Count > 0)
+        {
+            messages.Add(new
+            {
+                role = lastRole,
+                content = string.Join("\n\n", currentParts)
+            });
+        }
+
+        // Sicherstellen, dass die Messages mit "user" beginnen
+        if (messages.Count > 0)
+        {
+            var firstJson = JsonSerializer.Serialize(messages[0]);
+            var firstEl = JsonSerializer.Deserialize<JsonElement>(firstJson);
+            if (firstEl.GetProperty("role").GetString() != "user")
+            {
+                messages.Insert(0, new { role = "user", content = "Bitte überprüfe die folgende Konversation und die Arbeit des Agents." });
+            }
+        }
+        else
+        {
+            messages.Add(new { role = "user", content = "Es gibt keine Konversation zum Überprüfen." });
+        }
+
+        return messages;
+    }
+
+    /// <summary>
+    /// Baut einen ChatContext für Sub-Agents (Preparer/Review/Finalizer) auf,
+    /// wenn diese einen OpenAI-kompatiblen Provider nutzen.
+    /// </summary>
+    private ChatContext BuildSubAgentChatContext(SubAgentContext sub, string chainId, string sessionId, string apiToken)
+    {
+        // SystemPrompt als Text extrahieren (SubAgent hat List<object> mit { type, text } Blöcken)
+        var systemText = "";
+        if (sub.SystemPrompt != null)
+        {
+            var parts = new List<string>();
+            foreach (var block in sub.SystemPrompt)
+            {
+                var json = JsonSerializer.Serialize(block);
+                var el = JsonSerializer.Deserialize<JsonElement>(json);
+                if (el.TryGetProperty("text", out var t))
+                    parts.Add(t.GetString() ?? "");
+            }
+            systemText = string.Join("\n\n", parts);
+        }
+
+        return new ChatContext
+        {
+            ChainId = chainId,
+            SessionId = sessionId,
+            ModelId = sub.ModelId,
+            Provider = sub.Provider,
+            Workspace = sub.Workspace,
+            AgentId = sub.AgentId,
+            SystemPromptText = systemText,
+            UseMemory = sub.UseMemory,
+            WebSearchVersion = sub.WebSearchVersion,
+            MaxIterations = 20,
+            ApiToken = apiToken
+        };
+    }
+
+    // ── Shared Non-Streaming Tool Loop ──
+
+    /// <summary>
+    /// Optionale Callbacks für RunNonStreamingToolLoop.
+    /// </summary>
+    private class NonStreamingLoopCallbacks
+    {
+        /// <summary>Wird zu Beginn jeder Iteration aufgerufen (z.B. Typing-Indicator).</summary>
+        public Func<int, Task> OnIteration { get; set; }
+
+        /// <summary>SSE-Response für Client-Events. Null = keine SSE-Events.</summary>
+        public HttpResponse SseResponse { get; set; }
+        public CancellationToken SseCt { get; set; }
+
+        /// <summary>SSE-Event-Prefix (z.B. "review" → "review_text", "review_tool").</summary>
+        public string SsePrefix { get; set; }
+        public string AgentName { get; set; }
+
+        /// <summary>Tag für DB-Records (z.B. "review", "finalizer").</summary>
+        public string Tag { get; set; }
+
+        /// <summary>Ob Text-Embeddings in die Queue geschrieben werden.</summary>
+        public bool EnqueueEmbeddings { get; set; }
+
+        /// <summary>
+        /// Optionaler Tool-Executor. Parameter: (toolName, input, ct) → result.
+        /// Bei Fehler Exception werfen. Wenn null, wird Standard-Executor verwendet.
+        /// </summary>
+        public Func<string, JsonElement, CancellationToken, Task<string>> ExecuteTool { get; set; }
+    }
+
+    /// <summary>
+    /// Gemeinsamer Non-Streaming Tool-Loop für RunAgentChat und ChatNonStreaming.
+    /// Baut Payload, sendet API-Request, verarbeitet Content-Blöcke, führt Tools aus.
+    /// systemPrompt kann List&lt;object&gt; (Agent) oder string (ChatContext) sein.
+    /// </summary>
+    private async Task<(string text, int iterations)> RunNonStreamingToolLoop(
+        string modelId,
+        object systemPrompt,
+        ToolPayloadOptions toolOpts,
+        List<object> messages,
+        string chainId,
+        string sessionId,
+        string apiToken,
+        TokenUsage usage,
+        int baseIteration,
+        int maxIterations,
+        CancellationToken ct,
+        NonStreamingLoopCallbacks cb = null)
+    {
+        cb ??= new NonStreamingLoopCallbacks();
+        int iterations = 0;
+        var finalText = new StringBuilder();
+
+        while (iterations < maxIterations)
+        {
+            ct.ThrowIfCancellationRequested();
+            iterations++;
+            if (cb.OnIteration != null) await cb.OnIteration(iterations);
+
+            var payload = new Dictionary<string, object>
+            {
+                ["model"] = modelId,
+                ["max_tokens"] = 16384,
+                ["messages"] = messages
+            };
+
+            if (systemPrompt is List<object> spBlocks && spBlocks.Count > 0)
+                payload["system"] = spBlocks;
+            else if (systemPrompt is string spText && !string.IsNullOrEmpty(spText))
+                payload["system"] = spText;
+
+            AddToolsToPayload(payload, toolOpts with { Iteration = iterations });
+
+            var client = CreateClient(apiToken);
+            var json = JsonSerializer.Serialize(payload);
+            LogPayload(json, sessionId, chainId, baseIteration + iterations);
+            var httpContent = new StringContent(json, Encoding.UTF8, "application/json");
+
+            using var httpResp = await client.SendAsync(
+                new HttpRequestMessage(HttpMethod.Post, "https://api.anthropic.com/v1/messages") { Content = httpContent },
+                HttpCompletionOption.ResponseHeadersRead,
+                ct
+            );
+
+            TryUpdateKeyMeta(httpResp, apiToken);
+
+            if (!httpResp.IsSuccessStatusCode)
+            {
+                var errBody = await httpResp.Content.ReadAsStringAsync(ct);
+                var errMsg = $"API {(int)httpResp.StatusCode}: {errBody}";
+                await _db.SaveMessage(new MessageRecord
+                {
+                    ChainId = chainId, Iteration = baseIteration + iterations,
+                    Role = "system", Type = "error",
+                    Content = errMsg, IsError = true, Tag = cb.Tag
+                });
+                if (cb.SseResponse != null)
+                    await SseHelper.TryWriteSse(cb.SseResponse, $"{cb.SsePrefix}_error", new { error = errMsg }, cb.SseCt);
+                break;
+            }
+
+            var respJson = await httpResp.Content.ReadAsStringAsync(ct);
+            var respDoc = JsonSerializer.Deserialize<JsonElement>(respJson);
+
+            if (respDoc.TryGetProperty("usage", out var u))
+                TrackUsage(usage, u);
+
+            var stopReason = respDoc.TryGetProperty("stop_reason", out var sr) ? sr.GetString() ?? "" : "";
+            var contentArr = respDoc.TryGetProperty("content", out var c) ? c : default;
+            if (contentArr.ValueKind != JsonValueKind.Array) break;
+
+            var assistantContent = new List<object>();
+            var toolResults = new List<object>();
+
+            foreach (var block in contentArr.EnumerateArray())
+            {
+                var blockType = block.TryGetProperty("type", out var bt) ? bt.GetString() ?? "" : "";
+                if (blockType == "text")
+                {
+                    var text = block.GetProperty("text").GetString() ?? "";
+                    finalText.Append(text);
+                    assistantContent.Add(new { type = "text", text });
+
+                    var msgId = await _db.SaveMessage(new MessageRecord
+                    {
+                        ChainId = chainId, Iteration = baseIteration + iterations,
+                        Role = "assistant", Type = "text",
+                        Content = text, Tag = cb.Tag
+                    });
+                    if (cb.EnqueueEmbeddings)
+                        _embeddingBg?.Enqueue(msgId, chainId, sessionId, toolOpts.AgentId, "assistant", text);
+                    if (cb.SseResponse != null)
+                        await SseHelper.TryWriteSse(cb.SseResponse, $"{cb.SsePrefix}_text", new { text, agentName = cb.AgentName }, cb.SseCt);
+                }
+                else if (blockType == "tool_use")
+                {
+                    var toolId = block.GetProperty("id").GetString() ?? "";
+                    var toolName = block.GetProperty("name").GetString() ?? "";
+                    JsonElement inputEl;
+                    try { inputEl = block.GetProperty("input"); }
+                    catch { inputEl = JsonSerializer.Deserialize<JsonElement>("{}"); }
+
+                    assistantContent.Add(new { type = "tool_use", id = toolId, name = toolName, input = inputEl });
+
+                    await _db.SaveMessage(new MessageRecord
+                    {
+                        ChainId = chainId, Iteration = baseIteration + iterations,
+                        Role = "assistant", Type = "tool_use",
+                        ToolName = toolName, ToolCallId = toolId,
+                        Content = inputEl.ToString(), Tag = cb.Tag
+                    });
+
+                    ct.ThrowIfCancellationRequested();
+
+                    string toolResult;
+                    bool isError = false;
+                    try
+                    {
+                        toolResult = cb.ExecuteTool != null
+                            ? await cb.ExecuteTool(toolName, inputEl, ct)
+                            : await _toolService.ExecuteTool(toolName, inputEl, toolOpts.Workspace, _memoryService, toolOpts.AgentId, ct, vectorSearch: _vectorSearch, embeddingBg: _embeddingBg);
+                    }
+                    catch (OperationCanceledException) { throw; }
+                    catch (Exception ex) { toolResult = $"Fehler: {ex.Message}"; isError = true; }
+
+                    ct.ThrowIfCancellationRequested();
+
+                    toolResults.Add(new
+                    {
+                        type = "tool_result",
+                        tool_use_id = toolId,
+                        content = TruncateToolResult(toolResult),
+                        is_error = isError
+                    });
+
+                    await _db.SaveMessage(new MessageRecord
+                    {
+                        ChainId = chainId, Iteration = baseIteration + iterations,
+                        Role = "user", Type = "tool_result",
+                        ToolCallId = toolId,
+                        Content = toolResult, IsError = isError, Tag = cb.Tag
+                    });
+
+                    if (cb.SseResponse != null)
+                        await SseHelper.TryWriteSse(cb.SseResponse, $"{cb.SsePrefix}_tool", new { name = toolName, result = TruncateToolResult(toolResult), isError, agentName = cb.AgentName }, cb.SseCt);
+                }
+            }
+
+            messages.Add(new { role = "assistant", content = assistantContent });
+
+            if (stopReason != "tool_use" || toolResults.Count == 0)
+                break;
+
+            messages.Add(new { role = "user", content = toolResults });
+        }
+
+        return (finalText.ToString(), iterations);
+    }
+
+    /// <summary>
+    /// Agent-Chat (non-streaming API, SSE-Events für Client).
+    /// Wrapper um RunNonStreamingToolLoop für Review-/Finalizer-Agents.
+    /// </summary>
+    private Task<(string text, int iterations)> RunAgentChat(
+        HttpResponse response,
+        string modelId,
+        List<object> systemPrompt,
+        string agentId,
+        string agentWorkspace,
+        bool useMemory,
+        string webSearchVersion,
+        string agentToolChoice,
+        List<object> messages,
+        string chainId,
+        string sessionId,
+        string apiToken,
+        TokenUsage usage,
+        int baseIterations,
+        string agentType,
+        string agentName,
+        CancellationToken workCt,
+        CancellationToken sseCt)
+    {
+        return RunNonStreamingToolLoop(
+            modelId, systemPrompt,
+            new ToolPayloadOptions
+            {
+                Workspace = agentWorkspace, AgentId = agentId,
+                UseMemory = useMemory, WebSearchVersion = webSearchVersion,
+                ToolChoice = agentToolChoice
+            },
+            messages, chainId, sessionId, apiToken, usage,
+            baseIterations, 20, workCt,
+            new NonStreamingLoopCallbacks
+            {
+                SseResponse = response, SseCt = sseCt,
+                SsePrefix = agentType, AgentName = agentName,
+                Tag = agentType
+            });
+    }
+
+    /// <summary>
+    /// Non-Streaming Chat für Telegram. Gibt den finalen Antworttext zurück.
+    /// Wrapper um RunNonStreamingToolLoop mit Chain-Management und Embedding-Enqueue.
+    /// onIteration wird nach jeder Iteration aufgerufen (z.B. für Typing-Indicator).
+    /// </summary>
+    public async Task<string> ChatNonStreaming(
+        ChatContext ctx,
+        List<object> messages,
+        Func<int, Task> onIteration = null)
+    {
+        var sw = System.Diagnostics.Stopwatch.StartNew();
+        var usage = new TokenUsage();
+
+        var chain = new ChainRecord
+        {
+            ChainId = ctx.ChainId,
+            SessionId = ctx.SessionId,
+            Model = ctx.ModelId
+        };
+
+        try
+        {
+            var (text, iterations) = await RunNonStreamingToolLoop(
+                ctx.ModelId, ctx.SystemPromptText,
+                new ToolPayloadOptions
+                {
+                    Workspace = ctx.Workspace, AgentId = ctx.AgentId,
+                    UseMemory = ctx.UseMemory, WebSearchVersion = ctx.WebSearchVersion,
+                    ToolChoice = "auto"
+                },
+                messages, ctx.ChainId, ctx.SessionId, ctx.ApiToken, usage,
+                0, ctx.MaxIterations, CancellationToken.None,
+                new NonStreamingLoopCallbacks
+                {
+                    OnIteration = onIteration,
+                    EnqueueEmbeddings = true,
+                    ExecuteTool = (name, input, ct) =>
+                        _toolService.ExecuteTool(name, input, ctx.Workspace, _memoryService, ctx.AgentId, ct,
+                            vectorSearch: _vectorSearch, embeddingBg: _embeddingBg, db: _db,
+                            chatService: _chatService, anthropicService: this, openAiService: _openAiService)
+                });
+
+            var finalStopReason = text.Length > 0 ? "end_turn" : "error";
+            await FinalizeChain(chain, usage, iterations, finalStopReason, sw);
+            return text;
+        }
+        catch (Exception ex)
+        {
+            await _db.SaveMessage(new MessageRecord
+            {
+                ChainId = ctx.ChainId, Iteration = 0,
+                Role = "system", Type = "error",
+                Content = $"Fehler: {ex.Message}", IsError = true
+            });
+            await FinalizeChain(chain, usage, 0, "error", sw);
+            return "";
+        }
+    }
+}

Services/AnthropicService.Cli.cs

@@ -0,0 +1,530 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Gott.Endpoints;
+using Gott.Models;
+using Microsoft.AspNetCore.Http;
+
+namespace Gott.Services;
+
+public partial class AnthropicService
+{
+    /// <summary>
+    /// Streaming-Chat über die Claude CLI.
+    /// Die CLI verwendet das lokale Token aus ~/.claude/.credentials.json.
+    /// </summary>
+    public async Task StreamChatViaCli(
+        HttpResponse response,
+        string modelId,
+        List<object> systemPrompt,
+        List<object> messages,
+        string chainId,
+        string workspace = null,
+        bool allowUserChoice = false,
+        bool planMode = false,
+        bool webSearch = false,
+        string sessionId = null,
+        string agentId = null,
+        RemoteConnectionManager remoteMgr = null,
+        CancellationToken workCt = default,
+        CancellationToken sseCt = default)
+    {
+        if (_cliService == null || !_cliService.IsAvailable)
+        {
+            await SseHelper.TryWriteSse(response, "error", new { error = "Claude CLI nicht verfügbar" }, sseCt);
+            await SseHelper.TryWriteSse(response, "done", new { chainId }, sseCt);
+            return;
+        }
+
+        var sw = System.Diagnostics.Stopwatch.StartNew();
+        var usage = new TokenUsage();
+        var fullText = new StringBuilder();
+        var tempImagePaths = new List<string>();
+        string mcpConfigPath = null;
+        bool isUserChoice = false;
+
+        var chain = new ChainRecord
+        {
+            ChainId = chainId,
+            SessionId = sessionId,
+            Model = modelId
+        };
+
+        try
+        {
+            // MCP-Config generieren (immer – für ask_user_choice, optional Memory-Tools + remote_execute)
+            var hasRemote = remoteMgr != null && !string.IsNullOrEmpty(sessionId) && remoteMgr.GetBySessionId(sessionId) != null;
+            mcpConfigPath = GenerateMcpConfig(sessionId, agentId, hasRemote);
+
+            // System-Prompt als Text extrahieren
+            var systemText = new StringBuilder();
+            if (systemPrompt != null)
+            {
+                foreach (var block in systemPrompt)
+                {
+                    var json = JsonSerializer.Serialize(block);
+                    var el = JsonSerializer.Deserialize<JsonElement>(json);
+                    if (el.TryGetProperty("text", out var t))
+                        systemText.AppendLine(t.GetString());
+                }
+            }
+
+
+            // Letzte User-Message als Prompt extrahieren
+            var prompt = ExtractLastUserText(messages) ?? "";
+
+            // Bild-Attachments aus letzter User-Message als Temp-Dateien speichern
+            // (CLI kann Bilder nicht inline empfangen, aber per Read-Tool lesen)
+            var imageRefs = ExtractLastUserImageRefs(messages, tempImagePaths);
+            if (!string.IsNullOrEmpty(imageRefs))
+            {
+                prompt = imageRefs + "\n" + prompt;
+            }
+
+            // Konversations-History als Kontext zum Prompt hinzufügen
+            var historyContext = BuildHistoryContext(messages);
+            if (!string.IsNullOrEmpty(historyContext))
+            {
+                prompt = $"<conversation_history>\n{historyContext}\n</conversation_history>\n\n<current_request>\n{prompt}\n</current_request>";
+            }
+
+            string choiceToolCallId = null;
+
+            var result = await _cliService.ChatStreamingAsync(
+                prompt,
+                async evt =>
+                {
+                    switch (evt.Type)
+                    {
+                        case CliEventType.TextStart:
+                            await SseHelper.TryWriteSse(response, "text_start", new { index = 0 }, sseCt);
+                            break;
+                        case CliEventType.TextDelta:
+                            fullText.Append(evt.Text);
+                            await SseHelper.TryWriteSse(response, "text_delta", new { text = evt.Text }, sseCt);
+                            break;
+                        case CliEventType.TextEnd:
+                            await SseHelper.TryWriteSse(response, "text_end", new { }, sseCt);
+                            break;
+                        case CliEventType.ToolStart:
+                        {
+                            // Text-Puffer flushen bevor Tool-Use gespeichert wird (korrekte Reihenfolge in DB)
+                            if (fullText.Length > 0)
+                            {
+                                await _db.SaveMessage(new MessageRecord
+                                {
+                                    ChainId = chainId,
+                                    Iteration = 1,
+                                    Role = "assistant",
+                                    Type = "text",
+                                    Content = fullText.ToString()
+                                });
+                                fullText.Clear();
+                            }
+                            var mappedName = MapCliToolName(evt.ToolName);
+                            await SseHelper.TryWriteSse(response, "tool_start", new { name = mappedName, id = evt.ToolId }, sseCt);
+                            break;
+                        }
+                        case CliEventType.ToolEnd:
+                        {
+                            var mappedName = MapCliToolName(evt.ToolName);
+                            var mappedInput = MapCliToolInput(evt.ToolName, evt.ToolInput);
+                            // Tool-Use in DB speichern (damit Poll die Tools anzeigt)
+                            await _db.SaveMessage(new MessageRecord
+                            {
+                                ChainId = chainId,
+                                Iteration = 1,
+                                Role = "assistant",
+                                Type = "tool_use",
+                                ToolName = mappedName,
+                                ToolCallId = evt.ToolId,
+                                Content = mappedInput
+                            });
+                            await SseHelper.TryWriteSse(response, "tool_end", new { name = mappedName, id = evt.ToolId, input = mappedInput }, sseCt);
+
+                            // ask_user_choice via MCP: TCS erstellen + SSE user_choice Event
+                            if (mappedName == "ask_user_choice")
+                            {
+                                try
+                                {
+                                    var choiceInput = JsonSerializer.Deserialize<JsonElement>(mappedInput);
+                                    var cQuestion = choiceInput.TryGetProperty("question", out var cq) ? cq.GetString() ?? "" : "";
+                                    var cChoices = new List<string>();
+                                    if (choiceInput.TryGetProperty("choices", out var cc) && cc.ValueKind == JsonValueKind.Array)
+                                        foreach (var cOpt in cc.EnumerateArray())
+                                            cChoices.Add(cOpt.GetString() ?? "");
+
+                                    // Alte Antwort entfernen (falls vorhanden)
+                                    InternalEndpoint.ChoiceAnswers.TryRemove(sessionId, out _);
+
+                                    // SSE Event mit viaCli-Flag → Frontend zeigt Buttons + nutzt choice-respond Endpoint
+                                    choiceToolCallId = evt.ToolId;
+                                    await SseHelper.TryWriteSse(response, "user_choice", new
+                                    {
+                                        toolCallId = evt.ToolId,
+                                        question = cQuestion,
+                                        choices = cChoices,
+                                        viaCli = true
+                                    }, sseCt);
+
+                                    isUserChoice = true;
+                                }
+                                catch (JsonException) { /* Input nicht parsbar – MCP-Server gibt Fehler */ }
+                            }
+                            break;
+                        }
+                        case CliEventType.ToolResult:
+                        {
+                            // Tool-Result in DB speichern (damit es beim Neuladen sichtbar ist)
+                            var resultContent = SseHelper.TruncateToolResult(evt.ToolResultContent ?? "");
+                            await _db.SaveMessage(new MessageRecord
+                            {
+                                ChainId = chainId,
+                                Iteration = 1,
+                                Role = "user",
+                                Type = "tool_result",
+                                ToolCallId = evt.ToolId,
+                                Content = resultContent,
+                                IsError = evt.ToolResultIsError
+                            });
+                            // SSE Event an Client senden
+                            await SseHelper.TryWriteSse(response, "tool_result", new
+                            {
+                                id = evt.ToolId,
+                                result = resultContent,
+                                isError = evt.ToolResultIsError
+                            }, sseCt);
+                            break;
+                        }
+                    }
+                },
+                modelId: modelId,
+                systemPrompt: systemText.Length > 0 ? systemText.ToString() : null,
+                workspace: workspace,
+                hasWorkspace: !string.IsNullOrEmpty(workspace),
+                planMode: planMode,
+                webSearch: webSearch,
+                mcpConfigPath: mcpConfigPath,
+                cancellationToken: workCt
+            );
+
+            // Bei CLI-Fehler → Fehlermeldung an Client senden und in DB speichern
+            if (!result.Success && !isUserChoice)
+            {
+                var errorMsg = !string.IsNullOrEmpty(result.Error) ? result.Error : "CLI hat keine Antwort geliefert";
+                // Error in DB speichern (damit er beim Neuladen sichtbar ist)
+                await _db.SaveMessage(new MessageRecord
+                {
+                    ChainId = chainId,
+                    Iteration = 1,
+                    Role = "system",
+                    Type = "error",
+                    Content = $"CLI-Fehler: {errorMsg}"
+                });
+                await SseHelper.TryWriteSse(response, "error", new { error = $"CLI-Fehler: {errorMsg}" }, sseCt);
+            }
+
+            // Antwort in DB speichern
+            if (fullText.Length > 0)
+            {
+                await _db.SaveMessage(new MessageRecord
+                {
+                    ChainId = chainId,
+                    Iteration = 1,
+                    Role = "assistant",
+                    Type = "text",
+                    Content = fullText.ToString()
+                });
+            }
+
+            // Token-Usage vom CLI-Result übernehmen
+            usage.InputTokens = result.InputTokens;
+            usage.OutputTokens = result.OutputTokens;
+            usage.CacheReadTokens = result.CacheReadTokens;
+            usage.CacheCreationTokens = result.CacheCreationTokens;
+
+            var stopReason = isUserChoice ? "awaiting_user_choice" : (result.Success ? "end_turn" : "error");
+            await FinalizeChain(chain, usage, result.NumTurns > 0 ? result.NumTurns : 1, stopReason, sw);
+
+            await SseHelper.TryWriteSse(response, "done", new
+            {
+                model = modelId,
+                inputTokens = result.InputTokens,
+                outputTokens = result.OutputTokens,
+                cacheCreationTokens = result.CacheCreationTokens,
+                cacheReadTokens = result.CacheReadTokens,
+                costUsd = result.CostUsd,
+                iterations = result.NumTurns > 0 ? result.NumTurns : 1,
+                chainId,
+                durationMs = sw.ElapsedMilliseconds,
+                stopReason,
+                viaCli = true
+            }, sseCt);
+        }
+        catch (OperationCanceledException) when (workCt.IsCancellationRequested)
+        {
+            // Stop-Button gedrückt → CLI-Prozess wurde gestoppt
+            // Wenn ask_user_choice aktiv war: als awaiting_user_choice markieren,
+            // damit die nächste Chain den Kontext (Frage + Optionen) behält.
+            var stoppedReason = isUserChoice ? "awaiting_user_choice" : "stopped";
+            await FinalizeChain(chain, usage, 1, stoppedReason, sw);
+            await SseHelper.TryWriteSse(response, "done", new
+            {
+                model = modelId,
+                chainId,
+                durationMs = sw.ElapsedMilliseconds,
+                stopReason = stoppedReason,
+                viaCli = true
+            }, CancellationToken.None);
+        }
+        catch (OperationCanceledException)
+        {
+            // Client-Disconnect (sseCt gecancelled, aber NICHT workCt)
+            // CLI-Prozess läuft weiter im Hintergrund – hier nur Chain finalisieren
+            // (sollte nicht mehr passieren, da CLI jetzt workCt nutzt)
+            await FinalizeChain(chain, usage, 1, "client_disconnected", sw);
+        }
+        catch (Exception ex)
+        {
+            var errorMsg = $"CLI-Fehler: {ex.Message}";
+            await _db.SaveMessage(new MessageRecord
+            {
+                ChainId = chainId,
+                Iteration = 1,
+                Role = "system",
+                Type = "error",
+                Content = errorMsg
+            });
+            await SseHelper.TryWriteSse(response, "error", new { error = errorMsg }, sseCt);
+            await FinalizeChain(chain, usage, 1, "error", sw);
+            await SseHelper.TryWriteSse(response, "done", new
+            {
+                model = modelId,
+                chainId,
+                durationMs = sw.ElapsedMilliseconds,
+                stopReason = "error",
+                viaCli = true
+            }, sseCt);
+        }
+        finally
+        {
+            // Temp-Bilddateien aufräumen
+            CleanupTempImages(tempImagePaths);
+
+            // MCP-Config Temp-Datei aufräumen
+            if (mcpConfigPath != null)
+            {
+                try { File.Delete(mcpConfigPath); } catch { }
+            }
+        }
+    }
+
+    /// <summary>
+    /// Mappt CLI-Tool-Namen (Edit, Write, Bash, etc.) auf gott-Tool-Namen (edit_file, write_file, etc.).
+    /// </summary>
+    private static string MapCliToolName(string cliName)
+    {
+        return cliName switch
+        {
+            "Edit" => "edit_file",
+            "Write" => "write_file",
+            "Read" => "read_file",
+            "Bash" => "execute",
+            "Glob" => "list_files",
+            "Grep" => "search_files",
+            "WebSearch" => "web_search",
+            "WebFetch" => "web_fetch",
+            "NotebookEdit" => "notebook_edit",
+            "mcp__gott-remote__remote_execute" => "remote_execute",
+            _ => cliName?.StartsWith("mcp__") == true ? cliName.Split("__").LastOrDefault() ?? cliName : cliName
+        };
+    }
+
+    /// <summary>
+    /// Mappt CLI-Tool-Input-Felder auf gott-Konventionen (z.B. file_path→path, old_string→old_text).
+    /// </summary>
+    private static string MapCliToolInput(string cliToolName, string inputJson)
+    {
+        if (string.IsNullOrEmpty(inputJson)) return inputJson;
+
+        try
+        {
+            var input = JsonSerializer.Deserialize<JsonElement>(inputJson);
+            if (input.ValueKind != JsonValueKind.Object) return inputJson;
+
+            switch (cliToolName)
+            {
+                case "Edit":
+                {
+                    // file_path → path, old_string → old_text, new_string → new_text
+                    var mapped = new Dictionary<string, object>();
+                    foreach (var prop in input.EnumerateObject())
+                    {
+                        var key = prop.Name switch
+                        {
+                            "file_path" => "path",
+                            "old_string" => "old_text",
+                            "new_string" => "new_text",
+                            _ => prop.Name
+                        };
+                        mapped[key] = prop.Value;
+                    }
+                    return JsonSerializer.Serialize(mapped);
+                }
+                case "Write":
+                {
+                    // file_path → path
+                    var mapped = new Dictionary<string, object>();
+                    foreach (var prop in input.EnumerateObject())
+                    {
+                        var key = prop.Name == "file_path" ? "path" : prop.Name;
+                        mapped[key] = prop.Value;
+                    }
+                    return JsonSerializer.Serialize(mapped);
+                }
+                case "Read":
+                {
+                    // file_path → path
+                    var mapped = new Dictionary<string, object>();
+                    foreach (var prop in input.EnumerateObject())
+                    {
+                        var key = prop.Name == "file_path" ? "path" : prop.Name;
+                        mapped[key] = prop.Value;
+                    }
+                    return JsonSerializer.Serialize(mapped);
+                }
+                case "Bash":
+                {
+                    // command bleibt gleich
+                    return inputJson;
+                }
+                default:
+                    return inputJson;
+            }
+        }
+        catch
+        {
+            return inputJson;
+        }
+    }
+
+    /// <summary>
+    /// Baut einen Kontext-String aus der Konversations-History.
+    /// </summary>
+    private static string BuildHistoryContext(List<object> messages)
+    {
+        var sb = new StringBuilder();
+        // Letzte Message überspringen wenn es ein Text-Prompt ist (wird separat als current_request gesendet).
+        // Wenn die letzte Message ein tool_result ist (z.B. Choice-Antwort), NICHT überspringen.
+        int takeCount = messages.Count;
+        if (messages.Count > 0)
+        {
+            var lastJson = JsonSerializer.Serialize(messages[messages.Count - 1]);
+            var lastEl = JsonSerializer.Deserialize<JsonElement>(lastJson);
+            bool lastIsToolResult = false;
+            if (lastEl.TryGetProperty("content", out var lc) && lc.ValueKind == JsonValueKind.Array)
+            {
+                foreach (var b in lc.EnumerateArray())
+                {
+                    var bType = b.TryGetProperty("type", out var bt) ? bt.GetString() ?? "" : "";
+                    if (bType == "tool_result") { lastIsToolResult = true; break; }
+                }
+            }
+            if (!lastIsToolResult)
+                takeCount = messages.Count - 1;
+        }
+        foreach (var msg in messages.Take(takeCount))
+        {
+            var json = JsonSerializer.Serialize(msg);
+            var el = JsonSerializer.Deserialize<JsonElement>(json);
+            if (!el.TryGetProperty("role", out var role)) continue;
+            var roleStr = role.GetString() ?? "";
+
+            if (el.TryGetProperty("content", out var content))
+            {
+                if (content.ValueKind == JsonValueKind.String)
+                {
+                    sb.AppendLine($"[{roleStr}]: {content.GetString()}");
+                }
+                else if (content.ValueKind == JsonValueKind.Array)
+                {
+                    foreach (var block in content.EnumerateArray())
+                    {
+                        var blockType = block.TryGetProperty("type", out var bt) ? bt.GetString() ?? "" : "";
+                        if (blockType == "text" && block.TryGetProperty("text", out var txt))
+                        {
+                            sb.AppendLine($"[{roleStr}]: {txt.GetString()}");
+                        }
+                        else if (blockType == "tool_use" && block.TryGetProperty("name", out var tn) && tn.GetString() == "ask_user_choice")
+                        {
+                            if (block.TryGetProperty("input", out var inp))
+                            {
+                                var q = inp.TryGetProperty("question", out var qq) ? qq.GetString() ?? "" : "";
+                                var opts = new List<string>();
+                                if (inp.TryGetProperty("choices", out var cc) && cc.ValueKind == JsonValueKind.Array)
+                                    foreach (var o in cc.EnumerateArray()) opts.Add(o.GetString() ?? "");
+                                sb.AppendLine($"[assistant]: Ich habe gefragt: \"{q}\" mit Optionen: {string.Join(", ", opts)}");
+                            }
+                        }
+                        else if (blockType == "tool_result" && block.TryGetProperty("content", out var trContent))
+                        {
+                            sb.AppendLine($"[user]: Du hast gewählt: \"{trContent.GetString()}\"");
+                        }
+                    }
+                }
+            }
+        }
+        return sb.ToString().Trim();
+    }
+
+    /// <summary>
+    /// Generiert eine temporäre MCP-Config-Datei für die Claude CLI.
+    /// Enthält den MCP-Server für remote_execute.
+    /// </summary>
+    private string GenerateMcpConfig(string sessionId, string agentId = null, bool hasRemote = false)
+    {
+        // Port aus Konfiguration oder Default
+        var port = 19000;
+        var scriptPath = Path.Combine(AppContext.BaseDirectory, "scripts", "mcp-remote-execute.py");
+
+        // Fallback: Quell-Verzeichnis prüfen (für Dev-Modus)
+        if (!File.Exists(scriptPath))
+        {
+            var projectRoot = Path.GetDirectoryName(AppPaths.WwwRoot) ?? AppContext.BaseDirectory;
+            var srcPath = Path.Combine(projectRoot, "scripts", "mcp-remote-execute.py");
+            if (File.Exists(srcPath)) scriptPath = srcPath;
+        }
+
+        var env = new Dictionary<string, string>
+        {
+            ["GOTT_API_URL"] = $"http://localhost:{port}",
+            ["GOTT_SESSION_ID"] = sessionId ?? "",
+            ["GOTT_AUTH_TOKEN"] = Endpoints.InternalEndpoint.InternalToken,
+            ["GOTT_AGENT_ID"] = agentId ?? "",
+            ["GOTT_HAS_REMOTE"] = hasRemote ? "true" : "false"
+        };
+
+        var config = new
+        {
+            mcpServers = new Dictionary<string, object>
+            {
+                ["gott-remote"] = new
+                {
+                    command = "python3",
+                    args = new[] { scriptPath },
+                    env
+                }
+            }
+        };
+
+        var json = System.Text.Json.JsonSerializer.Serialize(config, new System.Text.Json.JsonSerializerOptions { WriteIndented = true });
+        var tempPath = Path.Combine(Path.GetTempPath(), $"gott-mcp-{sessionId}.json");
+        File.WriteAllText(tempPath, json);
+        return tempPath;
+    }
+}

Services/AnthropicService.Streaming.cs

@@ -0,0 +1,750 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Text.Json;
+using System.Threading;
+using System.Threading.Tasks;
+using Gott.Models;
+using Microsoft.AspNetCore.Http;
+
+namespace Gott.Services;
+
+public partial class AnthropicService
+{
+    public async Task StreamChat(
+        HttpResponse response,
+        string modelId,
+        List<object> systemPrompt,
+        List<object> messages,
+        string chainId,
+        string workspace,
+        string apiToken,
+        string sessionId = null,
+        string agentId = null,
+        string userId = null,
+        bool useMemory = true,
+        string webSearchVersion = null,
+        int maxIterations = 100,
+        string toolChoice = "any",
+        SubAgentContext review = null,
+        SubAgentContext finalizer = null,
+        bool allowUserChoice = true,
+        bool planMode = false,
+        bool useAutoContext = true,
+        bool useGitHubSearch = false,
+        bool useSerperSearch = false,
+        CancellationToken workCt = default,
+        CancellationToken hardCt = default,
+        CancellationToken sseCt = default,
+        RemoteConnectionManager remoteMgr = null)
+    {
+        var sw = System.Diagnostics.Stopwatch.StartNew();
+        var usage = new TokenUsage();
+        int iterations = 0;
+        int reviewRound = 0;
+        string lastStopReason = "";
+        int promptTrimRetries = 0;
+
+        var chain = new ChainRecord
+        {
+            ChainId = chainId,
+            SessionId = sessionId,
+            Model = modelId
+        };
+
+        try
+        {
+            // ── Automatische Kontext-Injektion via Embedding-Suche ──
+            if (useAutoContext && _vectorSearch != null && systemPrompt != null && messages.Count > 0)
+            {
+                try
+                {
+                    // Letzte User-Message als Query extrahieren
+                    var lastUserText = ExtractLastUserText(messages);
+                    if (!string.IsNullOrWhiteSpace(lastUserText))
+                    {
+                        var contextResults = await _vectorSearch.SearchAsync(lastUserText, agentId, topN: 5, minScore: 0.45f);
+                        // Nur Ergebnisse aus anderen Sessions (nicht aktuelle Chain) und nicht zu kurze
+                        contextResults.RemoveAll(r => r.ChainId == chainId || (r.TextPreview?.Length ?? 0) < 20);
+                        // Memory-Dateien durchsuchen
+                        var memoryResults = await _vectorSearch.SearchMemoryFilesAsync(lastUserText, agentId, topN: 3, minScore: 0.45f);
+
+                        if (contextResults.Count > 0 || memoryResults.Count > 0)
+                        {
+                            var ctxSb = new StringBuilder();
+                            ctxSb.AppendLine("\n<recalled_context>");
+                            ctxSb.AppendLine("Die folgende Information wurde automatisch abgerufen und könnte relevant sein:");
+                            foreach (var r in contextResults)
+                            {
+                                var date = DateTime.TryParse(r.CreatedAt, out var dt) ? dt.ToString("yyyy-MM-dd HH:mm") : r.CreatedAt;
+                                ctxSb.AppendLine($"- [Gespräch, {r.Role}, {date}]: {r.TextPreview}");
+                            }
+                            foreach (var r in memoryResults)
+                            {
+                                ctxSb.AppendLine($"- [Memory, {r.FilePath}]: {r.TextPreview}");
+                            }
+                            ctxSb.AppendLine("</recalled_context>");
+                            systemPrompt.Add(new { type = "text", text = ctxSb.ToString() });
+                        }
+                    }
+                }
+                catch (Exception ex)
+                {
+                    Console.WriteLine($"[AutoContext] Error: {ex.Message}");
+                }
+            }
+
+            while (iterations < maxIterations)
+            {
+                // Hard-Stop: Sofortiger Abbruch aus while-Loop (Doppel-Klick Stop)
+                hardCt.ThrowIfCancellationRequested();
+                workCt.ThrowIfCancellationRequested();
+                iterations++;
+
+                var payload = new Dictionary<string, object>
+                {
+                    ["model"] = modelId,
+                    ["max_tokens"] = 16384,
+                    ["cache_control"] = new { type = "ephemeral" },
+                    ["messages"] = messages,
+                    ["stream"] = true
+                };
+
+                if (systemPrompt != null && systemPrompt.Count > 0)
+                    payload["system"] = systemPrompt;
+
+                var hasRemote = remoteMgr?.GetBySessionId(sessionId) != null;
+                AddToolsToPayload(payload, new ToolPayloadOptions
+                {
+                    Workspace = workspace,
+                    AgentId = agentId,
+                    UseMemory = useMemory,
+                    WebSearchVersion = webSearchVersion,
+                    ToolChoice = toolChoice,
+                    Iteration = iterations,
+                    AllowUserChoice = allowUserChoice,
+                    PlanMode = planMode,
+                    IncludeRemote = hasRemote,
+                    IncludeGitHubSearch = useGitHubSearch && _toolService.HasGitHubToken,
+                    IncludeSerperSearch = useSerperSearch && _toolService.HasSerperKey
+                });
+
+                var client = CreateClient(apiToken);
+                var json = JsonSerializer.Serialize(payload, new JsonSerializerOptions { WriteIndented = true });
+                LogPayload(json, sessionId, chainId, iterations);
+                var httpContent = new StringContent(json, Encoding.UTF8, "application/json");
+
+                using var httpResp = await client.SendAsync(
+                    new HttpRequestMessage(HttpMethod.Post, "https://api.anthropic.com/v1/messages") { Content = httpContent },
+                    HttpCompletionOption.ResponseHeadersRead,
+                    workCt
+                );
+
+                TryUpdateKeyMeta(httpResp, apiToken);
+
+                if (!httpResp.IsSuccessStatusCode)
+                {
+                    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 SseHelper.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,
+                        Role = "system", Type = "error",
+                        Content = errMsg, IsError = true
+                    });
+                    await SseHelper.TryWriteSse(response, "error", new { error = errMsg }, sseCt);
+                    await FinalizeChain(chain, usage, iterations, "error", sw);
+                    await SseHelper.TryWriteSse(response, "done", new { chainId = chain.ChainId }, sseCt);
+                    return;
+                }
+
+                var (stopReason, assistantContent, executedTools, streamErrorInfo) = await ProcessStream(response, httpResp, usage, workspace, agentId, workCt, sseCt, remoteMgr, sessionId, userId, apiToken);
+                lastStopReason = stopReason;
+                promptTrimRetries = 0; // Erfolgreicher API-Call → Retry-Counter resetten
+
+                messages.Add(new { role = "assistant", content = assistantContent });
+
+                // Assistant-Blöcke persistieren
+                foreach (var block in assistantContent)
+                {
+                    var blockJson = JsonSerializer.Serialize(block);
+                    var el = JsonSerializer.Deserialize<JsonElement>(blockJson);
+                    var blockType = el.GetProperty("type").GetString() ?? "";
+
+                    if (blockType == "text")
+                    {
+                        var textContent = el.GetProperty("text").GetString();
+                        var msgId = await _db.SaveMessage(new MessageRecord
+                        {
+                            ChainId = chainId, Iteration = iterations,
+                            Role = "assistant", Type = "text",
+                            Content = textContent
+                        });
+                        _embeddingBg?.Enqueue(msgId, chainId, sessionId, agentId, "assistant", textContent ?? "");
+                    }
+                    else if (blockType == "tool_use")
+                    {
+                        await _db.SaveMessage(new MessageRecord
+                        {
+                            ChainId = chainId, Iteration = iterations,
+                            Role = "assistant", Type = "tool_use",
+                            ToolName = el.GetProperty("name").GetString(),
+                            ToolCallId = el.GetProperty("id").GetString(),
+                            Content = el.GetProperty("input").ToString()
+                        });
+                    }
+                    else if (blockType == "server_tool_use")
+                    {
+                        await _db.SaveMessage(new MessageRecord
+                        {
+                            ChainId = chainId, Iteration = iterations,
+                            Role = "assistant", Type = "server_tool_use",
+                            Content = el.GetRawText()
+                        });
+                    }
+                    else if (blockType == "web_search_tool_result")
+                    {
+                        // Raw-JSON speichern für History-Rebuild (API braucht den vollständigen Block)
+                        await _db.SaveMessage(new MessageRecord
+                        {
+                            ChainId = chainId, Iteration = iterations,
+                            Role = "assistant", Type = "web_search_result",
+                            Content = el.GetRawText()
+                        });
+                    }
+                    else if (blockType.EndsWith("_tool_result"))
+                    {
+                        // Generische Server-Tool-Results (bash_code_execution_tool_result, code_execution_tool_result etc.)
+                        await _db.SaveMessage(new MessageRecord
+                        {
+                            ChainId = chainId, Iteration = iterations,
+                            Role = "assistant", Type = "server_tool_result",
+                            Content = el.GetRawText()
+                        });
+                    }
+                }
+
+                // Tool Results persistieren
+                foreach (var tr in executedTools)
+                {
+                    await _db.SaveMessage(new MessageRecord
+                    {
+                        ChainId = chainId, Iteration = iterations,
+                        Role = "user", Type = "tool_result",
+                        ToolCallId = tr.Id,
+                        Content = tr.Result,
+                        IsError = tr.IsError
+                    });
+                }
+
+                if (stopReason != "tool_use")
+                {
+                    // ── Review-Agent Phase ──
+                    if (review != null && stopReason == "end_turn" && reviewRound < review.MaxReviewIterations)
+                    {
+                        var reviewResult = await RunReview(response, review, messages, chainId, workspace, sessionId, apiToken, usage, iterations, reviewRound, workCt, sseCt);
+                        iterations += reviewResult.ReviewIterationCount;
+                        reviewRound++;
+
+                        if (reviewResult.HasFeedback)
+                        {
+                            // Feedback als User-Message an Worker zurückgeben → nächste Iteration
+                            messages.Add(new Dictionary<string, object>
+                            {
+                                ["role"] = "user",
+                                ["content"] = new List<object> { new { type = "text", text = reviewResult.Feedback } }
+                            });
+                            await _db.SaveMessage(new MessageRecord
+                            {
+                                ChainId = chainId, Iteration = iterations,
+                                Role = "user", Type = "text",
+                                Content = reviewResult.Feedback
+                            });
+                            continue; // → nächste Worker-Iteration
+                        }
+                    }
+
+                    // ── Finalizer-Agent Phase ──
+                    if (finalizer != null && stopReason == "end_turn")
+                    {
+                        var finalizerIterations = await RunFinalizer(response, finalizer, messages, chainId, workspace, sessionId, apiToken, usage, iterations, workCt, sseCt);
+                        iterations += finalizerIterations;
+                    }
+
+                    var finalStopReason = string.IsNullOrEmpty(stopReason) ? "unexpected_end" : stopReason;
+                    await FinalizeChain(chain, usage, iterations, finalStopReason, sw, streamErrorInfo);
+                    await SseHelper.TryWriteSse(response, "done", new
+                    {
+                        model = modelId,
+                        inputTokens = usage.InputTokens,
+                        outputTokens = usage.OutputTokens,
+                        cacheCreationTokens = usage.CacheCreationTokens,
+                        cacheReadTokens = usage.CacheReadTokens,
+                        iterations,
+                        chainId,
+                        durationMs = sw.ElapsedMilliseconds,
+                        stopReason = finalStopReason,
+                        streamErrorInfo,
+                        planMode
+                    }, sseCt);
+                    return;
+                }
+
+                var toolResults = new List<object>();
+                foreach (var tr in executedTools)
+                {
+                    toolResults.Add(new
+                    {
+                        type = "tool_result",
+                        tool_use_id = tr.Id,
+                        content = TruncateToolResult(tr.Result),
+                        is_error = tr.IsError
+                    });
+                }
+
+                messages.Add(new { role = "user", content = toolResults });
+
+                // Hard-Stop Check nach Tool-Ausführung: Sofort raus statt nächste Iteration
+                hardCt.ThrowIfCancellationRequested();
+            }
+
+            await FinalizeChain(chain, usage, iterations, "max_iterations", sw);
+            await SseHelper.TryWriteSse(response, "error", new { error = "Max iterations erreicht" }, sseCt);
+            await SseHelper.TryWriteSse(response, "done", new { chainId = chain.ChainId }, sseCt);
+        }
+        catch (OperationCanceledException) when (workCt.IsCancellationRequested || hardCt.IsCancellationRequested)
+        {
+            // Stop-Button gedrückt (workCt oder hardCt wurde gecancelled)
+            await FinalizeChain(chain, usage, iterations, "stopped", sw);
+            // sseCt ist hier bereits cancelled (gelinkt mit workCt), daher CancellationToken.None
+            // Der SSE-Stream zum Client ist noch offen – nur der Stop-Button hat ausgelöst
+            await SseHelper.TryWriteSse(response, "done", new
+            {
+                model = modelId,
+                inputTokens = usage.InputTokens,
+                outputTokens = usage.OutputTokens,
+                cacheCreationTokens = usage.CacheCreationTokens,
+                cacheReadTokens = usage.CacheReadTokens,
+                iterations,
+                chainId,
+                durationMs = sw.ElapsedMilliseconds,
+                stopReason = "stopped",
+                planMode
+            }, CancellationToken.None);
+        }
+        catch (Exception) when (workCt.IsCancellationRequested || hardCt.IsCancellationRequested)
+        {
+            // Stream-Dispose durch CancellationToken-Registration löst
+            // ObjectDisposedException/IOException aus statt OperationCanceledException.
+            // Wenn workCt/hardCt gecancelled ist, ist das ein regulärer Stop.
+            await FinalizeChain(chain, usage, iterations, "stopped", sw);
+            // sseCt ist hier bereits cancelled (gelinkt mit workCt), daher CancellationToken.None
+            await SseHelper.TryWriteSse(response, "done", new
+            {
+                model = modelId,
+                inputTokens = usage.InputTokens,
+                outputTokens = usage.OutputTokens,
+                cacheCreationTokens = usage.CacheCreationTokens,
+                cacheReadTokens = usage.CacheReadTokens,
+                iterations,
+                chainId,
+                durationMs = sw.ElapsedMilliseconds,
+                stopReason = "stopped",
+                planMode
+            }, CancellationToken.None);
+        }
+        catch (OperationCanceledException)
+        {
+            // Client-Disconnect (cancellationToken gecancelled, aber NICHT workCt/hardCt)
+            // Agent-Arbeit ist leider schon abgebrochen – Chain als "client_disconnected" finalisieren
+            // (sollte durch TryWriteSse eigentlich nicht mehr passieren)
+            await FinalizeChain(chain, usage, iterations, "client_disconnected", sw);
+        }
+        catch (Exception ex)
+        {
+            // Unerwarteter Fehler – in DB speichern und versuchen an Client zu senden
+            var errMsg = $"Stream-Fehler: {ex.Message}";
+            await _db.SaveMessage(new MessageRecord
+            {
+                ChainId = chainId, Iteration = iterations,
+                Role = "system", Type = "error",
+                Content = errMsg, IsError = true
+            });
+            await FinalizeChain(chain, usage, iterations, "error", sw);
+            await SseHelper.TryWriteSse(response, "error", new { error = errMsg }, sseCt);
+            await SseHelper.TryWriteSse(response, "done", new { chainId = chain.ChainId }, sseCt);
+        }
+    }
+
+    private async Task<(string StopReason, List<object> Content, List<ToolResult> Tools, string StreamErrorInfo)> ProcessStream(
+        HttpResponse response,
+        HttpResponseMessage httpResp,
+        TokenUsage usage,
+        string workspace,
+        string agentId = null,
+        CancellationToken workCt = default,
+        CancellationToken sseCt = default,
+        RemoteConnectionManager remoteMgr = null,
+        string sessionId = null,
+        string userId = null,
+        string apiToken = null)
+    {
+        var stream = await httpResp.Content.ReadAsStreamAsync(workCt);
+        // Bei Cancellation den Stream disposen, damit ReadLineAsync sofort abbricht.
+        // StreamReader.ReadLineAsync propagiert den CancellationToken nicht zuverlässig
+        // an den underlying NetworkStream – der Read blockiert sonst bis Anthropic
+        // das nächste Chunk sendet (kann bei extended thinking Minuten dauern).
+        using var ctReg = workCt.Register(() => { try { stream.Dispose(); } catch { } });
+        using var reader = new StreamReader(stream);
+
+        var stopReason = "";
+        var assistantContent = new List<object>();
+        var currentToolId = "";
+        var currentToolName = "";
+        var currentToolInputJson = new StringBuilder();
+        var currentTextBlock = new StringBuilder();
+
+        var blockTypes = new Dictionary<int, string>();
+        var webSearchResultBlocks = new Dictionary<int, object>();
+        var webSearchSources = new Dictionary<int, List<object>>();
+        var serverToolResultBlocks = new Dictionary<int, object>(); // bash_code_execution_tool_result, code_execution_tool_result etc.
+        var executedTools = new List<ToolResult>();
+        var streamErrors = new List<object>();
+
+        string line;
+        while ((line = await reader.ReadLineAsync(workCt)) != null)
+        {
+            if (!line.StartsWith("data: ")) continue;
+            var data = line["data: ".Length..];
+            if (string.IsNullOrWhiteSpace(data)) continue;
+
+            JsonElement evt;
+            try { evt = JsonSerializer.Deserialize<JsonElement>(data); }
+            catch { continue; }
+
+            var evtType = evt.TryGetProperty("type", out var t) ? t.GetString() ?? "" : "";
+
+            switch (evtType)
+            {
+                case "message_start":
+                {
+                    if (evt.TryGetProperty("message", out var msg) &&
+                        msg.TryGetProperty("usage", out var u))
+                        TrackUsage(usage, u);
+                    break;
+                }
+
+                case "content_block_start":
+                {
+                    var idx = evt.GetProperty("index").GetInt32();
+                    var cb = evt.GetProperty("content_block");
+                    var cbType = cb.GetProperty("type").GetString() ?? "";
+                    blockTypes[idx] = cbType;
+
+                    if (cbType == "text")
+                    {
+                        currentTextBlock.Clear();
+                        await SseHelper.TryWriteSse(response, "text_start", new { index = idx }, sseCt);
+                    }
+                    else if (cbType == "tool_use")
+                    {
+                        if (currentTextBlock.Length > 0)
+                        {
+                            assistantContent.Add(new { type = "text", text = currentTextBlock.ToString() });
+                            currentTextBlock.Clear();
+                        }
+                        currentToolId = cb.GetProperty("id").GetString() ?? "";
+                        currentToolName = cb.GetProperty("name").GetString() ?? "";
+                        currentToolInputJson.Clear();
+                        await SseHelper.TryWriteSse(response, "tool_start", new { name = currentToolName, id = currentToolId }, sseCt);
+                    }
+                    else if (cbType == "server_tool_use")
+                    {
+                        if (currentTextBlock.Length > 0)
+                        {
+                            assistantContent.Add(new { type = "text", text = currentTextBlock.ToString() });
+                            currentTextBlock.Clear();
+                        }
+                        currentToolId = cb.GetProperty("id").GetString() ?? "";
+                        currentToolName = cb.GetProperty("name").GetString() ?? "";
+                        currentToolInputJson.Clear();
+                        await SseHelper.TryWriteSse(response, "web_search_start", new { name = currentToolName, id = currentToolId }, sseCt);
+                    }
+                    else if (cbType == "web_search_tool_result")
+                    {
+                        var rawBlock = JsonSerializer.Deserialize<JsonElement>(cb.GetRawText());
+                        webSearchResultBlocks[idx] = rawBlock;
+                        webSearchSources[idx] = ExtractWebSearchSources(cb);
+                    }
+                    else if (cbType.EndsWith("_tool_result"))
+                    {
+                        // Generische Server-Tool-Results (bash_code_execution_tool_result, code_execution_tool_result etc.)
+                        serverToolResultBlocks[idx] = JsonSerializer.Deserialize<JsonElement>(cb.GetRawText());
+                    }
+                    break;
+                }
+
+                case "content_block_delta":
+                {
+                    var delta = evt.GetProperty("delta");
+                    var deltaType = delta.GetProperty("type").GetString() ?? "";
+
+                    if (deltaType == "text_delta")
+                    {
+                        var text = delta.GetProperty("text").GetString() ?? "";
+                        currentTextBlock.Append(text);
+                        await SseHelper.TryWriteSse(response, "text_delta", new { text }, sseCt);
+                    }
+                    else if (deltaType == "input_json_delta")
+                    {
+                        var partial = delta.GetProperty("partial_json").GetString() ?? "";
+                        currentToolInputJson.Append(partial);
+                    }
+                    break;
+                }
+
+                case "content_block_stop":
+                {
+                    var idx = evt.GetProperty("index").GetInt32();
+                    if (blockTypes.TryGetValue(idx, out var bt))
+                    {
+                        if (bt == "text")
+                        {
+                            var text = currentTextBlock.ToString();
+                            if (text.Length > 0)
+                            {
+                                assistantContent.Add(new { type = "text", text });
+                                await SseHelper.TryWriteSse(response, "text_end", new { }, sseCt);
+                            }
+                            currentTextBlock.Clear();
+                        }
+                        else if (bt == "tool_use")
+                        {
+                            JsonElement inputEl;
+                            try { inputEl = JsonSerializer.Deserialize<JsonElement>(currentToolInputJson.ToString()); }
+                            catch { inputEl = JsonSerializer.Deserialize<JsonElement>("{}"); }
+
+                            assistantContent.Add(new
+                            {
+                                type = "tool_use",
+                                id = currentToolId,
+                                name = currentToolName,
+                                input = inputEl
+                            });
+
+                            // ask_user_choice: NICHT ausführen, sondern als SSE-Event an Client senden
+                            if (currentToolName == ToolService.AskUserChoiceToolName)
+                            {
+                                var question = inputEl.TryGetProperty("question", out var q) ? q.GetString() ?? "" : "";
+                                var choices = new List<string>();
+                                if (inputEl.TryGetProperty("choices", out var c))
+                                {
+                                    if (c.ValueKind == JsonValueKind.Array)
+                                    {
+                                        foreach (var ch in c.EnumerateArray())
+                                            choices.Add(ch.GetString() ?? "");
+                                    }
+                                    else if (c.ValueKind == JsonValueKind.String)
+                                    {
+                                        // Fallback: Claude hat einen einzelnen String statt Array gesendet
+                                        choices.Add(c.GetString() ?? "");
+                                    }
+                                }
+
+                                await SseHelper.TryWriteSse(response, "user_choice", new
+                                {
+                                    toolCallId = currentToolId,
+                                    question,
+                                    choices
+                                }, sseCt);
+
+                                // Stream restlich konsumieren ohne weitere Verarbeitung
+                                // (Claude sendet nach dem tool_use noch message_delta mit stop_reason)
+                                stopReason = "awaiting_user_choice";
+                                continue;
+                            }
+
+                            // Cancellation prüfen bevor Tool ausgeführt wird
+                            workCt.ThrowIfCancellationRequested();
+
+                            string toolResult;
+                            bool isError = false;
+                            try { toolResult = await _toolService.ExecuteTool(currentToolName, inputEl, workspace, _memoryService, agentId, workCt, remoteMgr: remoteMgr, sessionId: sessionId, vectorSearch: _vectorSearch, embeddingBg: _embeddingBg, db: _db, chatService: _chatService, anthropicService: this, openAiService: _openAiService, userId: userId, telegramService: _telegramService, apiToken: apiToken); }
+                            catch (OperationCanceledException) { throw; }
+                            catch (Exception ex) { toolResult = $"Fehler: {ex.Message}"; isError = true; }
+
+                            workCt.ThrowIfCancellationRequested();
+                            executedTools.Add(new ToolResult(currentToolId, toolResult, isError));
+
+                            await SseHelper.TryWriteSse(response, "tool_end", new
+                            {
+                                name = currentToolName,
+                                input = currentToolInputJson.ToString(),
+                                result = toolResult,
+                                isError
+                            }, sseCt);
+                        }
+                        else if (bt == "server_tool_use")
+                        {
+                            // Server-side tool (Web Search) – Anthropic führt es aus, wir speichern nur die Anfrage
+                            JsonElement inputEl;
+                            try { inputEl = JsonSerializer.Deserialize<JsonElement>(currentToolInputJson.ToString()); }
+                            catch { inputEl = JsonSerializer.Deserialize<JsonElement>("{}"); }
+
+                            assistantContent.Add(new
+                            {
+                                type = "server_tool_use",
+                                id = currentToolId,
+                                name = currentToolName,
+                                input = inputEl
+                            });
+                        }
+                        else if (bt == "web_search_tool_result")
+                        {
+                            // Web-Search-Ergebnis von Anthropic – als Raw-JSON in assistantContent aufnehmen
+                            assistantContent.Add(webSearchResultBlocks[idx]);
+                            var sources = webSearchSources.TryGetValue(idx, out var s) ? s : new List<object>();
+                            await SseHelper.TryWriteSse(response, "web_search_end", new { id = currentToolId, sources }, sseCt);
+                        }
+                        else if (bt.EndsWith("_tool_result") && serverToolResultBlocks.TryGetValue(idx, out var srvResultBlock))
+                        {
+                            // Generische Server-Tool-Results (bash_code_execution_tool_result, code_execution_tool_result etc.)
+                            assistantContent.Add(srvResultBlock);
+                        }
+                    }
+                    break;
+                }
+
+                case "message_delta":
+                {
+                    if (evt.TryGetProperty("delta", out var d))
+                    {
+                        if (d.TryGetProperty("stop_reason", out var sr))
+                        {
+                            // Nicht überschreiben wenn bereits auf awaiting_user_choice gesetzt
+                            if (stopReason != "awaiting_user_choice")
+                                stopReason = sr.GetString() ?? "";
+
+                            // Bei problematischen stop_reasons Debug-Infos sammeln
+                            if (stopReason is "unexpected_end" or "max_tokens")
+                            {
+                                var debugInfo = new Dictionary<string, object>
+                                {
+                                    ["event"] = "message_delta",
+                                    ["stop_reason"] = stopReason,
+                                    ["output_tokens"] = usage.OutputTokens,
+                                    ["text_length"] = currentTextBlock.Length,
+                                    ["timestamp"] = DateTime.UtcNow.ToString("o")
+                                };
+                                if (d.TryGetProperty("stop_sequence", out var ss) && ss.ValueKind != JsonValueKind.Null)
+                                    debugInfo["stop_sequence"] = ss.GetString();
+                                streamErrors.Add(debugInfo);
+                            }
+                        }
+                    }
+                    if (evt.TryGetProperty("usage", out var u2) &&
+                        u2.TryGetProperty("output_tokens", out var ot))
+                        usage.OutputTokens += ot.GetInt64();
+                    break;
+                }
+
+                case "error":
+                {
+                    // API Error-Event (z.B. overloaded_error)
+                    var errorInfo = new Dictionary<string, object>
+                    {
+                        ["event"] = "error",
+                        ["timestamp"] = DateTime.UtcNow.ToString("o"),
+                        ["raw"] = data
+                    };
+                    if (evt.TryGetProperty("error", out var err))
+                    {
+                        if (err.TryGetProperty("type", out var errType))
+                            errorInfo["error_type"] = errType.GetString();
+                        if (err.TryGetProperty("message", out var errMsg))
+                            errorInfo["error_message"] = errMsg.GetString();
+                    }
+                    streamErrors.Add(errorInfo);
+                    break;
+                }
+            }
+        }
+
+        if (currentTextBlock.Length > 0)
+            assistantContent.Add(new { type = "text", text = currentTextBlock.ToString() });
+
+        // Stream-Fehler als JSON serialisieren (null wenn keine Fehler)
+        string streamErrorInfo = streamErrors.Count > 0
+            ? JsonSerializer.Serialize(streamErrors)
+            : null;
+
+        return (stopReason, assistantContent, executedTools, streamErrorInfo);
+    }
+
+    /// <summary>
+    /// Extrahiert Web-Search-Sources aus einem web_search_tool_result-Block.
+    /// </summary>
+    private static List<object> ExtractWebSearchSources(JsonElement block)
+    {
+        var sources = new List<object>();
+        if (block.TryGetProperty("content", out var searchContent) && searchContent.ValueKind == JsonValueKind.Array)
+        {
+            foreach (var item in searchContent.EnumerateArray())
+            {
+                var itemType = item.TryGetProperty("type", out var it) ? it.GetString() : "";
+                if (itemType == "web_search_result")
+                {
+                    var url = item.TryGetProperty("url", out var u) ? u.GetString() ?? "" : "";
+                    var title = item.TryGetProperty("title", out var tt) ? tt.GetString() ?? "" : "";
+                    if (!string.IsNullOrEmpty(url))
+                        sources.Add(new { url, title });
+                }
+            }
+        }
+        return sources;
+    }
+
+    /// <summary>
+    /// Parst einen server_tool_use-Block und gibt (id, name, input) zurück.
+    /// </summary>
+    private static (string id, string name, JsonElement input) ParseServerToolUse(JsonElement block)
+    {
+        var toolId = block.GetProperty("id").GetString() ?? "";
+        var toolName = block.GetProperty("name").GetString() ?? "";
+        JsonElement inputEl;
+        try { inputEl = block.GetProperty("input"); }
+        catch { inputEl = JsonSerializer.Deserialize<JsonElement>("{}"); }
+        return (toolId, toolName, inputEl);
+    }
+
+    /// <summary>
+    /// Aktualisiert den TokenUsage-Tracker aus einem usage-JSON-Element.
+    /// </summary>
+    private static void TrackUsage(TokenUsage usage, JsonElement u)
+    {
+        if (u.TryGetProperty("input_tokens", out var it)) usage.InputTokens += it.GetInt64();
+        if (u.TryGetProperty("output_tokens", out var ot)) usage.OutputTokens += ot.GetInt64();
+        if (u.TryGetProperty("cache_creation_input_tokens", out var cc)) usage.CacheCreationTokens += cc.GetInt64();
+        if (u.TryGetProperty("cache_read_input_tokens", out var cr)) usage.CacheReadTokens += cr.GetInt64();
+    }
+}