diff --git a/apps/web/src/lib/attachments.ts b/apps/web/src/lib/attachments.ts
index af06c5c..264448f 100644
--- a/apps/web/src/lib/attachments.ts
+++ b/apps/web/src/lib/attachments.ts
@@ -56,19 +56,26 @@ export function inferLanguage(filename: string): string | null {
 
 export function flattenToMessage(attachments: Attachment[], text: string): string {
   if (attachments.length === 0) return text;
-  const blocks = attachments.map(a => {
-    // Pasted text is raw context, not code from a file — insert it verbatim with
-    // no ``` fence or provenance header. The chip only exists to keep the textarea
-    // tidy while composing; on send it should be exactly what the user pasted.
+  // Pasted text is raw context, not code from a file — insert it verbatim with no
+  // ``` fence or provenance header. It trails the typed text with a leading space
+  // so a leading slash command / prompt stays first and the paste reads as its
+  // continuation. File/line chips stay fenced provenance blocks, appended after.
+  const pasteBlocks: string[] = [];
+  const fencedBlocks: string[] = [];
+  for (const a of attachments) {
     if (a.kind === 'paste') {
-      return a.content;
+      pasteBlocks.push(a.content);
+      continue;
     }
     const fence = '```' + (a.language ?? '');
     const header =
       a.kind === 'lines'
         ? `// from: ${a.filename}:${a.range?.[0] ?? '?'}-${a.range?.[1] ?? '?'}`
         : `// from: ${a.filename}`;
-    return `${fence}\n${header}\n${a.content}\n\`\`\``;
-  });
-  return [...blocks, text].filter(Boolean).join('\n\n');
+    fencedBlocks.push(`${fence}\n${header}\n${a.content}\n\`\`\``);
+  }
+  // Typed text + pasted content on the same logical line (space-joined), then
+  // any fenced file blocks as separate paragraphs.
+  const lead = [text, ...pasteBlocks].filter(Boolean).join(' ');
+  return [lead, ...fencedBlocks].filter(Boolean).join('\n\n');
 }