diff --git a/documentation/docs/98-reference/.generated/compile-errors.md b/documentation/docs/98-reference/.generated/compile-errors.md
index 079b1d2a0a..7fc9f56cd1 100644
--- a/documentation/docs/98-reference/.generated/compile-errors.md
+++ b/documentation/docs/98-reference/.generated/compile-errors.md
@@ -63,7 +63,41 @@ Event attribute must be a JavaScript expression, not a string
 ### attribute_invalid_sequence_expression
 
 ```
-Sequence expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses
+Comma-separated expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses
+```
+
+```
+An attribute value cannot be a comma-separated sequence of expressions — in other words this is disallowed:
+```
+
+```
+```svelte
+<div class={size, color}>...</div>
+```
+```
+
+```
+Instead, make sure that the attribute value contains a single expression. In the example above it's likely that this was intended (see the [class documentation](class) for more details):
+```
+
+```
+```svelte
+<div class={[size, color]}>...</div>
+```
+```
+
+```
+If you _do_ need to use the comma operator for some reason, wrap the sequence in parentheses:
+```
+
+```
+```svelte
+<div class={(size, color)}>...</div>
+```
+```
+
+```
+[!NOTE] This will evaluate to `color`, ignoring `size`.
 ```
 
 ### attribute_invalid_type
diff --git a/packages/svelte/src/compiler/errors.js b/packages/svelte/src/compiler/errors.js
index 3997dbec32..ee2e759779 100644
--- a/packages/svelte/src/compiler/errors.js
+++ b/packages/svelte/src/compiler/errors.js
@@ -785,12 +785,12 @@ export function attribute_invalid_name(node, name) {
 }
 
 /**
- * Sequence expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses
+ * [!NOTE] This will evaluate to `color`, ignoring `size`.
  * @param {null | number | NodeLike} node
  * @returns {never}
  */
 export function attribute_invalid_sequence_expression(node) {
-	e(node, 'attribute_invalid_sequence_expression', `Sequence expressions are not allowed as attribute/directive values in runes mode, unless wrapped in parentheses\nhttps://svelte.dev/e/attribute_invalid_sequence_expression`);
+	e(node, 'attribute_invalid_sequence_expression', `[!NOTE] This will evaluate to \`color\`, ignoring \`size\`.\nhttps://svelte.dev/e/attribute_invalid_sequence_expression`);
 }
 
 /**