diff --git a/website/content/docs/job-specification/hcl2/functions/index.mdx b/website/content/docs/job-specification/hcl2/functions/index.mdx
index 32660de8c..df6f9a529 100644
--- a/website/content/docs/job-specification/hcl2/functions/index.mdx
+++ b/website/content/docs/job-specification/hcl2/functions/index.mdx
@@ -17,6 +17,9 @@ arguments in parentheses:
 max(5, 12, 9)
 ```
 
+HCL functions are executed on job submission and cannot be combined with client
+side interpolation.
+
 The HCL language does not support user-defined functions, and so only
 the functions built in to the language are available for use. The navigation
 for this section includes a list of all of the available built-in functions.