diff --git a/KLR/Trace/Term.lean b/KLR/Trace/Term.lean
index e1df1e1e..e6b8092f 100644
--- a/KLR/Trace/Term.lean
+++ b/KLR/Trace/Term.lean
@@ -676,7 +676,6 @@ def builtinEnv : List (Name × Term) := Id.run do
     let fn := .builtin name none
     let names : List Name := match name with
       | .str `builtin.python n => [.str `builtins n, .str .anonymous n]
-      | .str `builtin.isa n => [nisa n, name]
       | .str `builtin.typing n => [nt n, name]
       | .str `builtin.lang n => [nl n, name]
       | _ => [name]