diff --git a/.emacs.d/custom.el b/.emacs.d/custom.el
index 9be2dd7..bedcca7 100644
--- a/.emacs.d/custom.el
+++ b/.emacs.d/custom.el
@@ -78,10 +78,11 @@
                    mocha modus-themes monky monokai-theme multi-term
                    mustache-mode nyan-mode paredit popup prettier-js
                    projectile protobuf-mode python-mode request rjsx-mode
-                   ruby-mode rust-mode scala-ts-mode sql-indent swift-mode
-                   switch-window terraform-mode thrift tide tree-sitter tss
-                   tuareg typescript-mode use-package vterm web-mode wgrep
-                   wgsl-mode xref-js2 xterm-color yaml-mode zig-mode))
+                   ruby-mode rust-mode scala-ts-mode simple-httpd sql-indent
+                   swift-mode switch-window terraform-mode thrift tide
+                   tree-sitter tss tuareg typescript-mode use-package uuidgen
+                   vterm web-mode wgrep wgsl-mode xref-js2 xterm-color
+                   yaml-mode zig-mode))
  '(reb-re-syntax 'string)
  '(rmail-mail-new-frame t)
  '(safe-local-variable-values
diff --git a/site-lisp/doty-tools.el b/site-lisp/doty-tools.el
index 3105012..5b2c706 100644
--- a/site-lisp/doty-tools.el
+++ b/site-lisp/doty-tools.el
@@ -100,9 +100,12 @@ If it is a buffer object, just return it. If it names a file, visit the
  that buffer. Otherwise return nil."
   (cond
    ((bufferp buffer-or-file) buffer-or-file)
-   ((file-exists-p buffer-or-file) (find-file-noselect buffer-or-file))
+   ((file-exists-p (expand-file-name buffer-or-file))
+    (find-file-noselect (expand-file-name buffer-or-file)))
    ((length= (match-buffers buffer-or-file) 1)
-    (car (match-buffers buffer-or-file)))))
+    (car (match-buffers buffer-or-file)))
+   (t (error "file %s doesn't exist and does not name an open buffer"
+             buffer-or-file))))
 
 (defun doty-tools--open-file (filename &optional max-chars)
   "Visit FILENAME and return up to MAX-CHARS of its contents as a string.
@@ -404,9 +407,9 @@ Returns file path, modified status, major mode, size, line count, and more."
       (treesit-node-check node 'missing)))
 
 
-(defun doty-tools--map-buffer (buffer)
-  "Generate a map for BUFFER."
-  (with-current-buffer buffer
+(defun doty-tools--map-buffer (file-or-buffer)
+  "Generate a map for FILE-OR-BUFFER."
+  (with-current-buffer (doty-tools--buffer-or-file file-or-buffer)
     (let* ((registration (or (assoc (treesit-language-at (point-min))
                                     doty-tools--treesit-queries)
                              (error "Language '%s' not registered as a tree-sitter mapper"