diff --git a/.changeset/chain-of-thought-aria-controls.md b/.changeset/chain-of-thought-aria-controls.md
new file mode 100644
index 00000000..3b98aaa3
--- /dev/null
+++ b/.changeset/chain-of-thought-aria-controls.md
@@ -0,0 +1,5 @@
+---
+"ai-elements": patch
+---
+
+Fix ChainOfThought header aria-controls pointing at an element that is never rendered
diff --git a/packages/elements/__tests__/chain-of-thought.test.tsx b/packages/elements/__tests__/chain-of-thought.test.tsx
index a6e17eb4..9edc569a 100644
--- a/packages/elements/__tests__/chain-of-thought.test.tsx
+++ b/packages/elements/__tests__/chain-of-thought.test.tsx
@@ -68,6 +68,26 @@ describe("chainOfThought", () => {
 
     expect(onOpenChange).toHaveBeenCalledWith(true);
   });
+
+  it("points the header's aria-controls at the content", async () => {
+    const user = userEvent.setup();
+
+    render(
+      <ChainOfThought>
+        <ChainOfThoughtHeader />
+        <ChainOfThoughtContent>Steps</ChainOfThoughtContent>
+      </ChainOfThought>
+    );
+
+    const trigger = screen.getByRole("button");
+    await user.click(trigger);
+
+    expect(trigger).toHaveAttribute("aria-expanded", "true");
+    expect(trigger).toHaveAttribute(
+      "aria-controls",
+      screen.getByText("Steps").id
+    );
+  });
 });
 
 describe("chainOfThoughtHeader", () => {
diff --git a/packages/elements/src/chain-of-thought.tsx b/packages/elements/src/chain-of-thought.tsx
index f1b26601..42887718 100644
--- a/packages/elements/src/chain-of-thought.tsx
+++ b/packages/elements/src/chain-of-thought.tsx
@@ -60,9 +60,14 @@ export const ChainOfThought = memo(
 
     return (
       <ChainOfThoughtContext.Provider value={chainOfThoughtContext}>
-        <div className={cn("not-prose w-full space-y-4", className)} {...props}>
+        <Collapsible
+          className={cn("not-prose w-full space-y-4", className)}
+          onOpenChange={setIsOpen}
+          open={isOpen}
+          {...props}
+        >
           {children}
-        </div>
+        </Collapsible>
       </ChainOfThoughtContext.Provider>
     );
   }
@@ -74,29 +79,27 @@ export type ChainOfThoughtHeaderProps = ComponentProps<
 
 export const ChainOfThoughtHeader = memo(
   ({ className, children, ...props }: ChainOfThoughtHeaderProps) => {
-    const { isOpen, setIsOpen } = useChainOfThought();
+    const { isOpen } = useChainOfThought();
 
     return (
-      <Collapsible onOpenChange={setIsOpen} open={isOpen}>
-        <CollapsibleTrigger
+      <CollapsibleTrigger
+        className={cn(
+          "flex w-full items-center gap-2 text-muted-foreground text-sm transition-colors hover:text-foreground",
+          className
+        )}
+        {...props}
+      >
+        <BrainIcon className="size-4" />
+        <span className="flex-1 text-left">
+          {children ?? "Chain of Thought"}
+        </span>
+        <ChevronDownIcon
           className={cn(
-            "flex w-full items-center gap-2 text-muted-foreground text-sm transition-colors hover:text-foreground",
-            className
+            "size-4 transition-transform",
+            isOpen ? "rotate-180" : "rotate-0"
           )}
-          {...props}
-        >
-          <BrainIcon className="size-4" />
-          <span className="flex-1 text-left">
-            {children ?? "Chain of Thought"}
-          </span>
-          <ChevronDownIcon
-            className={cn(
-              "size-4 transition-transform",
-              isOpen ? "rotate-180" : "rotate-0"
-            )}
-          />
-        </CollapsibleTrigger>
-      </Collapsible>
+        />
+      </CollapsibleTrigger>
     );
   }
 );
@@ -179,21 +182,19 @@ export type ChainOfThoughtContentProps = ComponentProps<
 
 export const ChainOfThoughtContent = memo(
   ({ className, children, ...props }: ChainOfThoughtContentProps) => {
-    const { isOpen } = useChainOfThought();
+    useChainOfThought();
 
     return (
-      <Collapsible open={isOpen}>
-        <CollapsibleContent
-          className={cn(
-            "mt-2 space-y-3",
-            "data-[state=closed]:fade-out-0 data-[state=closed]:slide-out-to-top-2 data-[state=open]:slide-in-from-top-2 text-popover-foreground outline-none data-[state=closed]:animate-out data-[state=open]:animate-in",
-            className
-          )}
-          {...props}
-        >
-          {children}
-        </CollapsibleContent>
-      </Collapsible>
+      <CollapsibleContent
+        className={cn(
+          "mt-2 space-y-3",
+          "data-[state=closed]:fade-out-0 data-[state=closed]:slide-out-to-top-2 data-[state=open]:slide-in-from-top-2 text-popover-foreground outline-none data-[state=closed]:animate-out data-[state=open]:animate-in",
+          className
+        )}
+        {...props}
+      >
+        {children}
+      </CollapsibleContent>
     );
   }
 );