diff --git a/apps/web/src/components/ChatMarkdown.tsx b/apps/web/src/components/ChatMarkdown.tsx
index 821d1643ede09b1d2b22f25d5f382af82d8b2eed..dd0343ca990ec556219320c98648b70cc1aea99a 100644
--- a/apps/web/src/components/ChatMarkdown.tsx
+++ b/apps/web/src/components/ChatMarkdown.tsx
@@ -849,7 +849,7 @@ function MarkdownCodeBlock({
   theme,
   onRunShellCommand,
   isStreaming,
-  leadingActions,
+  viewToggle,
   canWrap = true,
   diagram = false,
   children,
@@ -860,9 +860,10 @@ function MarkdownCodeBlock({
   theme: "light" | "dark";
   onRunShellCommand?: ((command: string) => void) | undefined;
   isStreaming: boolean;
-  leadingActions?: ReactNode;
+  /** Switches between source and rendered content; sits left of copy in both views. */
+  viewToggle?: ReactNode;
   canWrap?: boolean;
-  /** Renders content instead of code, with actions below it like tables. */
+  /** Renders content frameless, with the code header's actions above it. */
   diagram?: boolean;
   children: ReactNode;
 }) {
@@ -942,12 +943,14 @@ function MarkdownCodeBlock({
 
   if (diagram) {
     return (
-      <div className="my-[0.65rem]" data-language={language}>
-        {children}
-        <div className="mt-0.5 flex items-center justify-between select-none">
-          {leadingActions}
+      // The transparent border and header padding match the code frame, so the
+      // actions stay in place when switching views.
+      <div className="my-[0.65rem] border border-transparent" data-language={language}>
+        <div className="flex items-center justify-end gap-0.5 pt-1.5 pr-1.5 select-none">
+          {viewToggle}
           {copyButton}
         </div>
+        {children}
       </div>
     );
   }
@@ -962,7 +965,6 @@ function MarkdownCodeBlock({
       headerProps={THREAD_FIND_IGNORE_PROPS}
       actions={
         <span className="flex items-center gap-0.5" role="toolbar" aria-label="Code block actions">
-          {leadingActions}
           {canWrap ? (
             <Tooltip>
               <TooltipTrigger
@@ -1000,6 +1002,7 @@ function MarkdownCodeBlock({
               <TooltipPopup side="top">Run in terminal</TooltipPopup>
             </Tooltip>
           ) : null}
+          {viewToggle}
           {copyButton}
         </span>
       }
@@ -1043,7 +1046,7 @@ function MarkdownMermaidCodeBlock({
       isStreaming={isStreaming}
       canWrap={!showDiagram}
       diagram={showDiagram}
-      leadingActions={
+      viewToggle={
         isStreaming ? null : (
           <Tooltip>
             <TooltipTrigger