diff --git a/src/lisp/lcp.lisp b/src/lisp/lcp.lisp
index 84736c9fe..514f2d242 100644
--- a/src/lisp/lcp.lisp
+++ b/src/lisp/lcp.lisp
@@ -22,6 +22,8 @@
 (in-package #:lcp)
 
 (defconstant +whitespace-chars+ '(#\Newline #\Space #\Return #\Linefeed #\Tab))
+(defconstant +vim-read-only+ "vim: readonly")
+(defconstant +emacs-read-only+ "-*- buffer-read-only: t; -*-")
 
 (defstruct raw-cpp
   (string "" :type string :read-only t))
@@ -1498,7 +1500,9 @@ written to CPP-OUT stream.  This source file will include the provided HPP-FILE.
 Original LCP-FILE is used just to insert a comment about the source of the
 code generation."
   (with-open-file (out capnp-file :direction :output :if-exists :supersede)
-    (format out "# Autogenerated using LCP from '~A'~%# DO NOT EDIT!~2%" lcp-file)
+    (format out "~@{# ~A~%~}" +emacs-read-only+ +vim-read-only+)
+    (format out "# DO NOT EDIT! Generated using LCP from '~A'~2%"
+            (file-namestring lcp-file))
     (format out "~A;~2%" capnp-id)
     (write-line "using Cxx = import \"/capnp/c++.capnp\";" out)
     (format out "$Cxx.namespace(\"~A::capnp\");~2%" *capnp-namespace*)
@@ -1569,7 +1573,9 @@ file."
       ;; cpp-code. This allows us to generate code which may rely on
       ;; evaluation done after the code definition.
       (with-open-file (out hpp-file :direction :output :if-exists :supersede)
-        (format out "// Autogenerated using LCP from '~A'~%// DO NOT EDIT!~2%" lcp-file)
+        (format out "~@{// ~A~%~}" +emacs-read-only+ +vim-read-only+)
+        (format out "// DO NOT EDIT! Generated using LCP from '~A'~2%"
+                (file-namestring lcp-file))
         (dolist (res (read-lcp lcp-file))
           (write-line (cpp-code res) out)))
       (when *cpp-namespaces*
@@ -1581,7 +1587,9 @@ file."
         ;; When we have either capnp or C++ code for the .cpp file, generate the .cpp file
         (when (or *cpp-impl* types-for-capnp)
           (with-open-file (out cpp-file :direction :output :if-exists :supersede)
-            (format out "// Autogenerated using LCP from '~A'~%// DO NOT EDIT!~2%" lcp-file)
+            (format out "~@{// ~A~%~}" +emacs-read-only+ +vim-read-only+)
+            (format out "// DO NOT EDIT! Generated using LCP from '~A'~2%"
+                    (file-namestring lcp-file))
             (format out "#include \"~A\"~2%" (file-namestring hpp-file))
             ;; First output the C++ code from the user
             (let (open-namespaces)