diff --git a/scripts/claude-bridge.js b/scripts/claude-bridge.js
index dff7356..da7b2b4 100644
--- a/scripts/claude-bridge.js
+++ b/scripts/claude-bridge.js
@@ -542,6 +542,12 @@ async function sendMessage(message, requestId, model = null, contextOverride = n
               if (block.type === 'text' && block.text) {
                 fullText += block.text;
                 sendEvent('text', { text: block.text });
+              } else if (block.type === 'thinking' && block.thinking) {
+                // Extended Thinking — als kollabierbaren Block senden
+                const thinkLines = block.thinking.split('\n').length;
+                const collapsed = `<details class="thinking-block"><summary>💭 Überlegung (${thinkLines} Zeilen)</summary>\n\n${block.thinking}\n\n</details>\n\n`;
+                fullText += collapsed;
+                sendEvent('text', { text: collapsed });
               } else if (block.type === 'tool_use') {
                 // Tool-Call von Main-Agent — manuell weiterreichen, damit
                 // der tool_use-Case weiter unten greift
diff --git a/src/lib/components/ChatPanel.svelte b/src/lib/components/ChatPanel.svelte
index edbc62d..45f694e 100644
--- a/src/lib/components/ChatPanel.svelte
+++ b/src/lib/components/ChatPanel.svelte
@@ -42,12 +42,38 @@
 
 	function renderMarkdown(text: string): string {
 		try {
-			return marked.parse(text) as string;
+			// Thinking-Blöcke erkennen und in <details> packen
+			const processed = collapseThinkingBlocks(text);
+			return marked.parse(processed) as string;
 		} catch {
 			return text;
 		}
 	}
 
+	/**
+	 * Erkennt "Denk-Blöcke" im Text und packt sie in Markdown-<details>.
+	 * Patterns: Absätze die mit typischen Überlegungs-Phrasen starten,
+	 * gefolgt von der eigentlichen Antwort.
+	 */
+	function collapseThinkingBlocks(text: string): string {
+		// Pattern: Text beginnt mit Analyse/Überlegungs-Block, dann kommt die Antwort
+		const thinkingPatterns = [
+			/^((?:(?:Lass mich|Ich (?:schaue|prüfe|analysiere|untersuche|überleg)|OK,? (?:lass|ich)|Gut,? (?:lass|ich)|Hmm|Also|Zunächst|Zuerst).*?\n(?:.*\n)*?))((?:\n(?:#{1,3} |(?:\*\*|Die |Das |Hier |Zusammen|Fertig|Erledigt|✅)).*[\s\S]*))/m,
+		];
+
+		for (const pattern of thinkingPatterns) {
+			const match = text.match(pattern);
+			if (match && match[1] && match[1].split('\n').length > 5) {
+				const thinkingPart = match[1].trim();
+				const answerPart = match[2].trim();
+				const lines = thinkingPart.split('\n').length;
+				return `<details class="thinking-block">\n<summary>💭 Überlegung (${lines} Zeilen)</summary>\n\n${thinkingPart}\n\n</details>\n\n${answerPart}`;
+			}
+		}
+
+		return text;
+	}
+
 	// Svelte Action: Copy-Buttons zu Code-Blöcken hinzufügen
 	function addCopyButtons(node: HTMLElement) {
 		function processCodeBlocks() {
@@ -1324,6 +1350,36 @@
 		background: var(--bg-hover, #333);
 	}
 
+	/* Thinking-Block (details/summary) */
+	.message-content :global(details.thinking-block) {
+		margin: 0.4rem 0;
+		border: 1px solid var(--border, #3a3a3a);
+		border-radius: 4px;
+		background: var(--bg-tertiary, #1e1e1e);
+	}
+
+	.message-content :global(details.thinking-block summary) {
+		padding: 0.4rem 0.6rem;
+		cursor: pointer;
+		font-size: 0.8rem;
+		color: var(--text-secondary, #888);
+		user-select: none;
+	}
+
+	.message-content :global(details.thinking-block summary:hover) {
+		color: var(--text-primary, #ccc);
+	}
+
+	.message-content :global(details.thinking-block[open]) {
+		padding-bottom: 0.4rem;
+	}
+
+	.message-content :global(details.thinking-block[open] > :not(summary)) {
+		padding: 0 0.6rem;
+		font-size: 0.8rem;
+		opacity: 0.8;
+	}
+
 	/* Markdown-Styles innerhalb von Nachrichten */
 	.message-content :global(p) {
 		margin: 0.3em 0;