diff --git a/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/file-viewer.tsx b/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/file-viewer.tsx
index 70c3ac9a99..cfae210046 100644
--- a/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/file-viewer.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/file-viewer.tsx
@@ -1025,6 +1025,7 @@ const DocxPreview = memo(function DocxPreview({
   file: WorkspaceFileRecord
   workspaceId: string
 }) {
+  const viewportRef = useRef<HTMLDivElement>(null)
   const containerRef = useRef<HTMLDivElement>(null)
   const {
     data: fileData,
@@ -1032,6 +1033,40 @@ const DocxPreview = memo(function DocxPreview({
     error: fetchError,
   } = useWorkspaceFileBinary(workspaceId, file.id, file.key)
   const [renderError, setRenderError] = useState<string | null>(null)
+  const [docxScale, setDocxScale] = useState(1)
+  const [scaledSize, setScaledSize] = useState<{ width: number; height: number } | null>(null)
+
+  const updateDocxScale = useCallback(() => {
+    const viewport = viewportRef.current
+    const container = containerRef.current
+    if (!viewport || !container) return
+
+    const intrinsicWidth = container.scrollWidth
+    const intrinsicHeight = container.scrollHeight
+    if (intrinsicWidth === 0 || intrinsicHeight === 0) return
+
+    const viewportStyle = window.getComputedStyle(viewport)
+    const paddingX =
+      Number.parseFloat(viewportStyle.paddingLeft) + Number.parseFloat(viewportStyle.paddingRight)
+    const availableWidth = Math.max(viewport.clientWidth - paddingX, 0)
+    const nextScale = availableWidth > 0 ? Math.min(1, availableWidth / intrinsicWidth) : 1
+
+    setDocxScale((prev) => (Math.abs(prev - nextScale) < 0.001 ? prev : nextScale))
+    setScaledSize((prev) => {
+      const next = {
+        width: intrinsicWidth * nextScale,
+        height: intrinsicHeight * nextScale,
+      }
+      if (
+        prev &&
+        Math.abs(prev.width - next.width) < 1 &&
+        Math.abs(prev.height - next.height) < 1
+      ) {
+        return prev
+      }
+      return next
+    })
+  }, [])
 
   useEffect(() => {
     if (!containerRef.current || !fileData) return
@@ -1042,12 +1077,18 @@ const DocxPreview = memo(function DocxPreview({
       try {
         const { renderAsync } = await import('docx-preview')
         if (cancelled || !containerRef.current) return
+        setRenderError(null)
+        setDocxScale(1)
+        setScaledSize(null)
         containerRef.current.innerHTML = ''
         await renderAsync(fileData, containerRef.current, undefined, {
           inWrapper: true,
           ignoreWidth: false,
           ignoreHeight: false,
         })
+        if (!cancelled) {
+          requestAnimationFrame(updateDocxScale)
+        }
       } catch (err) {
         if (!cancelled) {
           const msg = err instanceof Error ? err.message : 'Failed to render document'
@@ -1061,13 +1102,57 @@ const DocxPreview = memo(function DocxPreview({
     return () => {
       cancelled = true
     }
-  }, [fileData])
+  }, [fileData, updateDocxScale])
+
+  useEffect(() => {
+    const viewport = viewportRef.current
+    const container = containerRef.current
+    if (!viewport || !container) return
+
+    updateDocxScale()
+
+    const resizeObserver = new ResizeObserver(() => {
+      updateDocxScale()
+    })
+
+    resizeObserver.observe(viewport)
+    resizeObserver.observe(container)
+
+    return () => {
+      resizeObserver.disconnect()
+    }
+  }, [fileData, updateDocxScale])
 
   const error = resolvePreviewError(fetchError, renderError)
   if (error) return <PreviewError label='document' error={error} />
   if (isLoading) return DOCUMENT_SKELETON
 
-  return <div ref={containerRef} className='h-full w-full overflow-auto bg-white' />
+  return (
+    <div ref={viewportRef} className='h-full overflow-auto bg-[var(--surface-1)] p-4 sm:p-6'>
+      <div className='flex min-h-full justify-center'>
+        <div
+          className='shrink-0'
+          style={
+            scaledSize
+              ? {
+                  width: scaledSize.width,
+                  minHeight: scaledSize.height,
+                }
+              : undefined
+          }
+        >
+          <div
+            ref={containerRef}
+            className='origin-top'
+            style={{
+              transform: `scale(${docxScale})`,
+              transformOrigin: 'top center',
+            }}
+          />
+        </div>
+      </div>
+    </div>
+  )
 })
 
 const pptxSlideCache = new Map<string, string[]>()
diff --git a/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx b/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx
index 24a74a9265..3bc527a378 100644
--- a/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx
+++ b/apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx
@@ -4,6 +4,7 @@ import { createContext, memo, useCallback, useContext, useEffect, useMemo, useRe
 import { useRouter } from 'next/navigation'
 import rehypeSlug from 'rehype-slug'
 import remarkBreaks from 'remark-breaks'
+import remarkGfm from 'remark-gfm'
 import { Streamdown } from 'streamdown'
 import 'streamdown/styles.css'
 import { Checkbox } from '@/components/emcn'
@@ -74,7 +75,7 @@ export const PreviewPanel = memo(function PreviewPanel({
   return null
 })
 
-const REMARK_PLUGINS = [remarkBreaks]
+const REMARK_PLUGINS = [remarkGfm, remarkBreaks]
 const REHYPE_PLUGINS = [rehypeSlug]
 
 /**
@@ -404,12 +405,80 @@ const MarkdownPreview = memo(function MarkdownPreview({
   )
 })
 
+const HTML_PREVIEW_BASE_URL = 'about:srcdoc'
+
+const HTML_PREVIEW_CSP = [
+  "default-src 'none'",
+  "script-src 'unsafe-inline'",
+  "style-src 'unsafe-inline'",
+  'img-src data: blob:',
+  'font-src data:',
+  'media-src data: blob:',
+  "connect-src 'none'",
+  "form-action 'none'",
+  "frame-src 'none'",
+  "child-src 'none'",
+  "object-src 'none'",
+].join('; ')
+
+const HTML_PREVIEW_BOOTSTRAP = `<script>
+(() => {
+  const allowHref = (href) => href.startsWith('#') || /^\\s*javascript:/i.test(href)
+
+  document.addEventListener(
+    'click',
+    (event) => {
+      if (!(event.target instanceof Element)) return
+      const anchor = event.target.closest('a[href]')
+      if (!(anchor instanceof HTMLAnchorElement)) return
+      const href = anchor.getAttribute('href') || ''
+      if (allowHref(href)) return
+      event.preventDefault()
+    },
+    true
+  )
+
+  document.addEventListener(
+    'submit',
+    (event) => {
+      event.preventDefault()
+    },
+    true
+  )
+
+})()
+</script>`
+
+function buildHtmlPreviewDocument(content: string): string {
+  const headInjection = [
+    '<meta charset="utf-8">',
+    `<base href="${HTML_PREVIEW_BASE_URL}">`,
+    `<meta http-equiv="Content-Security-Policy" content="${HTML_PREVIEW_CSP}">`,
+    HTML_PREVIEW_BOOTSTRAP,
+  ].join('')
+
+  if (/<head[\s>]/i.test(content)) {
+    return content.replace(/<head(\s[^>]*)?>/i, (match) => `${match}${headInjection}`)
+  }
+
+  if (/<html[\s>]/i.test(content)) {
+    return content.replace(/<html(\s[^>]*)?>/i, (match) => `${match}<head>${headInjection}</head>`)
+  }
+
+  return `<!DOCTYPE html><html><head>${headInjection}</head><body>${content}</body></html>`
+}
+
 const HtmlPreview = memo(function HtmlPreview({ content }: { content: string }) {
+  // Run inline HTML/JS in an isolated iframe while blocking any navigation
+  // that would replace the preview with another document.
+  const wrappedContent = useMemo(() => buildHtmlPreviewDocument(content), [content])
+
   return (
     <div className='h-full overflow-hidden'>
       <iframe
-        srcDoc={content}
-        sandbox='allow-same-origin'
+        srcDoc={wrappedContent}
+        sandbox='allow-scripts'
+        referrerPolicy='no-referrer'
         title='HTML Preview'
         className='h-full w-full border-0 bg-white'
       />
diff --git a/apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts b/apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts
index c58ed8cb34..0906d97a22 100644
--- a/apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts
+++ b/apps/sim/app/workspace/[workspaceId]/home/hooks/use-chat.ts
@@ -2507,6 +2507,13 @@ export function useChat(
             return
           }
 
+          // A live SSE `complete` event is already terminal. Finalize immediately so follow-up
+          // sends do not get spuriously queued behind an already-finished response.
+          if (streamResult.sawComplete) {
+            finalize()
+            return
+          }
+
           await resumeOrFinalize({
             streamId: streamIdRef.current || userMessageId,
             assistantId,