diff --git a/frontend/src/components/UnifiedPromptModal.jsx b/frontend/src/components/UnifiedPromptModal.jsx
index 3052f06..4281866 100644
--- a/frontend/src/components/UnifiedPromptModal.jsx
+++ b/frontend/src/components/UnifiedPromptModal.jsx
@@ -1,4 +1,4 @@
-import { useState, useEffect, useRef } from 'react'
+import { useState, useEffect, useRef, useLayoutEffect } from 'react'
 import { api } from '../utils/api'
 import { X, Plus, Trash2, MoveUp, MoveDown, Code } from 'lucide-react'
 import PlaceholderPicker from './PlaceholderPicker'
@@ -66,6 +66,53 @@ function sanitizeDebugForPanel(dbg, resultType) {
   return o
 }
 
+/** Langer Inhalt: zunächst auf maxRem eingeklappt, „Mehr/Weniger anzeigen“ */
+function ExpandableCollapsible({ children, contentKey, maxRem = 28 }) {
+  const [expanded, setExpanded] = useState(false)
+  const wrapRef = useRef(null)
+  const [showToggle, setShowToggle] = useState(false)
+
+  useEffect(() => {
+    setExpanded(false)
+  }, [contentKey])
+
+  useLayoutEffect(() => {
+    const el = wrapRef.current
+    if (!el) return
+    if (expanded) {
+      setShowToggle(true)
+      return
+    }
+    setShowToggle(el.scrollHeight > el.clientHeight + 2)
+  }, [contentKey, expanded])
+
+  return (
+    <div>
+      <div
+        ref={wrapRef}
+        style={{
+          maxHeight: expanded ? 'none' : `${maxRem}rem`,
+          overflow: expanded ? 'visible' : 'hidden'
+        }}
+      >
+        {children}
+      </div>
+      {showToggle && (
+        <div style={{ marginTop: 10, textAlign: 'center' }}>
+          <button
+            type="button"
+            className="btn btn-secondary"
+            style={{ fontSize: 12, padding: '6px 14px' }}
+            onClick={() => setExpanded((e) => !e)}
+          >
+            {expanded ? 'Weniger anzeigen' : 'Mehr anzeigen'}
+          </button>
+        </div>
+      )}
+    </div>
+  )
+}
+
 function renderTestOutput(testResult) {
   if (!testResult) return null
   if (testResult.error) {
@@ -89,7 +136,7 @@ function renderTestOutput(testResult) {
     return <span style={{ color: 'var(--text3)' }}>Keine Ausgabe</span>
   }
 
-  const proseBox = (content) => (
+  const proseBox = (content, contentKey) => (
     <div
       style={{
         padding: 16,
@@ -102,7 +149,11 @@ function renderTestOutput(testResult) {
         textAlign: 'left'
       }}
     >
-      {content}
+      {contentKey != null ? (
+        <ExpandableCollapsible contentKey={contentKey}>{content}</ExpandableCollapsible>
+      ) : (
+        content
+      )}
     </div>
   )
 
@@ -123,23 +174,27 @@ function renderTestOutput(testResult) {
               {key}
             </div>
             {typeof val === 'string' ? (
-              proseBox(<Markdown text={val} />)
+              proseBox(
+                <Markdown text={val} />,
+                `pipe-${key}-${val.length}-${val.slice(0, 120)}`
+              )
             ) : (
-              <pre
-                style={{
-                  margin: 0,
-                  padding: 12,
-                  background: 'var(--bg)',
-                  borderRadius: 8,
-                  border: '1px solid var(--border)',
-                  fontSize: 12,
-                  overflow: 'auto',
-                  maxHeight: 360,
-                  textAlign: 'left'
-                }}
-              >
-                {JSON.stringify(val, null, 2)}
-              </pre>
+              <ExpandableCollapsible contentKey={`pipe-json-${key}-${JSON.stringify(val).slice(0, 200)}`} maxRem={22}>
+                <pre
+                  style={{
+                    margin: 0,
+                    padding: 12,
+                    background: 'var(--bg)',
+                    borderRadius: 8,
+                    border: '1px solid var(--border)',
+                    fontSize: 12,
+                    overflow: 'auto',
+                    textAlign: 'left'
+                  }}
+                >
+                  {JSON.stringify(val, null, 2)}
+                </pre>
+              </ExpandableCollapsible>
             )}
           </div>
         ))}
@@ -151,47 +206,54 @@ function renderTestOutput(testResult) {
     if (fmt === 'json') {
       try {
         const parsed = JSON.parse(out)
+        const jsonStr = JSON.stringify(parsed, null, 2)
         return (
-          <pre
-            style={{
-              margin: 0,
-              padding: 12,
-              background: 'var(--bg)',
-              borderRadius: 8,
-              border: '1px solid var(--border)',
-              fontSize: 12,
-              overflow: 'auto',
-              maxHeight: 480,
-              textAlign: 'left'
-            }}
-          >
-            {JSON.stringify(parsed, null, 2)}
-          </pre>
+          <ExpandableCollapsible contentKey={`json-out-${jsonStr.length}-${jsonStr.slice(0, 80)}`} maxRem={26}>
+            <pre
+              style={{
+                margin: 0,
+                padding: 12,
+                background: 'var(--bg)',
+                borderRadius: 8,
+                border: '1px solid var(--border)',
+                fontSize: 12,
+                overflow: 'auto',
+                textAlign: 'left'
+              }}
+            >
+              {jsonStr}
+            </pre>
+          </ExpandableCollapsible>
         )
       } catch {
-        return proseBox(<pre style={{ margin: 0, whiteSpace: 'pre-wrap' }}>{out}</pre>)
+        return proseBox(
+          <pre style={{ margin: 0, whiteSpace: 'pre-wrap' }}>{out}</pre>,
+          `json-fail-${out.length}-${out.slice(0, 80)}`
+        )
       }
     }
-    return proseBox(<Markdown text={out} />)
+    return proseBox(<Markdown text={out} />, `text-out-${out.length}-${out.slice(0, 120)}`)
   }
 
   if (typeof out === 'object') {
+    const jsonStr = JSON.stringify(out, null, 2)
     return (
-      <pre
-        style={{
-          margin: 0,
-          padding: 12,
-          background: 'var(--bg)',
-          borderRadius: 8,
-          border: '1px solid var(--border)',
-          fontSize: 12,
-          overflow: 'auto',
-          maxHeight: 480,
-          textAlign: 'left'
-        }}
-      >
-        {JSON.stringify(out, null, 2)}
-      </pre>
+      <ExpandableCollapsible contentKey={`obj-out-${jsonStr.length}-${jsonStr.slice(0, 120)}`} maxRem={26}>
+        <pre
+          style={{
+            margin: 0,
+            padding: 12,
+            background: 'var(--bg)',
+            borderRadius: 8,
+            border: '1px solid var(--border)',
+            fontSize: 12,
+            overflow: 'auto',
+            textAlign: 'left'
+          }}
+        >
+          {jsonStr}
+        </pre>
+      </ExpandableCollapsible>
     )
   }
 
diff --git a/frontend/src/utils/Markdown.jsx b/frontend/src/utils/Markdown.jsx
index 328fa8b..ece6419 100644
--- a/frontend/src/utils/Markdown.jsx
+++ b/frontend/src/utils/Markdown.jsx
@@ -1,5 +1,5 @@
 // Lightweight Markdown renderer – handles the subset used by the AI:
-// ## Headings, **bold**, bullet lists, numbered lists, line breaks
+// ## Headings, **bold**, bullet lists, numbered lists, fenced ``` code ```, line breaks
 
 export default function Markdown({ text }) {
   if (!text) return null
@@ -7,6 +7,19 @@ export default function Markdown({ text }) {
   const lines = text.split('\n')
   const elements = []
   let i = 0
+  let blockId = 0
+
+  const codeBlockStyle = {
+    margin: '10px 0',
+    padding: 12,
+    background: 'var(--surface2)',
+    borderRadius: 8,
+    border: '1px solid var(--border)',
+    overflow: 'auto',
+    fontSize: 12,
+    lineHeight: 1.5,
+    fontFamily: 'ui-monospace, Consolas, monospace'
+  }
 
   const parseLine = (line) => {
     // Parse inline **bold** and *italic*
@@ -39,6 +52,44 @@ export default function Markdown({ text }) {
   while (i < lines.length) {
     const line = lines[i]
 
+    // Fenced code block: ``` or ```lang
+    const trimmedStart = line.trimStart()
+    if (trimmedStart.startsWith('```')) {
+      const lang = trimmedStart.slice(3).trim() || null
+      i++
+      const codeLines = []
+      while (i < lines.length) {
+        if (lines[i].trim().startsWith('```')) {
+          i++
+          break
+        }
+        codeLines.push(lines[i])
+        i++
+      }
+      const code = codeLines.join('\n')
+      elements.push(
+        <div key={`code-${blockId++}`} style={{ margin: '10px 0' }}>
+          {lang && (
+            <div
+              style={{
+                fontSize: 10,
+                color: 'var(--text3)',
+                marginBottom: 6,
+                fontFamily: 'ui-monospace, monospace',
+                letterSpacing: 0.02
+              }}
+            >
+              {lang}
+            </div>
+          )}
+          <pre style={codeBlockStyle}>
+            <code style={{ color: 'var(--text1)', whiteSpace: 'pre', display: 'block' }}>{code}</code>
+          </pre>
+        </div>
+      )
+      continue
+    }
+
     // Skip empty lines (add spacing)
     if (line.trim() === '') {
       elements.push(<div key={i} style={{ height: 8 }} />)