diff --git a/.ocamlformat b/.ocamlformat
index 0fc5459..7a64b1e 100644
--- a/.ocamlformat
+++ b/.ocamlformat
@@ -1,4 +1,4 @@
-version=0.14.2
+version=0.17.0
 break-separators=before
 dock-collection-brackets=false
 break-sequences=true
diff --git a/src/pp.ml b/src/pp.ml
index 91673e6..0227704 100644
--- a/src/pp.ml
+++ b/src/pp.ml
@@ -108,7 +108,7 @@ let rec filter_map_tags t ~f =
     let t = filter_map_tags t ~f in
     match f tag with
     | None -> t
-    | Some tag -> Tag (tag, t) )
+    | Some tag -> Tag (tag, t))
   | Format f -> Format f
 
 module Render = struct
@@ -224,10 +224,10 @@ let chain l ~f =
             box ~indent:3
               (seq
                  (verbatim
-                    ( if i = 0 then
+                    (if i = 0 then
                       "   "
                     else
-                      "-> " ))
+                      "-> "))
                  (f x)))))
 
 module O = struct
diff --git a/src/pp.mli b/src/pp.mli
index 4b64844..f625ad3 100644
--- a/src/pp.mli
+++ b/src/pp.mli
@@ -177,16 +177,15 @@ val to_fmt_with_tags :
 
 (** Inject a classic formatter in a document.
 
-    Disclaimer: this function is to meant to help using [Pp] in
-    existing code that already use the [Format] module without having
-    to port everything to [Pp]. It is not meant as the normal way to
-    create [Pp.t] values.
-*)
+    Disclaimer: this function is to meant to help using [Pp] in existing code
+    that already use the [Format] module without having to port everything to
+    [Pp]. It is not meant as the normal way to create [Pp.t] values. *)
 val of_fmt : (Format.formatter -> 'a -> unit) -> 'a -> _ t
 
 (** {1 Ast} *)
 
 module Ast : sig
+  (** Stable representation useful for serialization *)
   type 'a t =
     | Nop
     | Seq of 'a t * 'a t
@@ -204,6 +203,9 @@ module Ast : sig
     | Tag of 'a * 'a t
 end
 
+(** [of_ast t] [Ast.t] to [Pp.t] *)
 val of_ast : 'a Ast.t -> 'a t
 
+(** [to_ast t] will try to convert [t] to [Ast.t]. When [t] contains values
+    constructed with [of_fmt], this function will fail and return [Error ()] *)
 val to_ast : 'a t -> ('a Ast.t, unit) result
diff --git a/test/tests.ml b/test/tests.ml
index cdea0ba..c78afc0 100644
--- a/test/tests.ml
+++ b/test/tests.ml
@@ -159,7 +159,7 @@ let%expect_test _ =
 let%expect_test _ =
   print
     (Pp.vbox
-       ( Pp.box (Pp.text "Error: something went wrong!")
+       (Pp.box (Pp.text "Error: something went wrong!")
        ++ Pp.cut
        ++ Pp.box (Pp.text "Here are a few things you can do:")
        ++ Pp.cut
@@ -180,7 +180,7 @@ let%expect_test _ =
                    ; "take a break from your keyboard"
                    ; "clear your head and try again"
                    ]
-            ] ));
+            ]));
   [%expect
     {|
     Error: something went wrong!
@@ -200,24 +200,24 @@ let%expect_test _ =
 let%expect_test _ =
   print
     (Pp.hovbox ~indent:2
-       ( Array.make 50 (Pp.char 'x')
+       (Array.make 50 (Pp.char 'x')
        |> Array.to_list
        |> Pp.concat
-            ~sep:(Pp.custom_break ~fits:("", 2, "") ~breaks:(" \\", -1, "")) ));
+            ~sep:(Pp.custom_break ~fits:("", 2, "") ~breaks:(" \\", -1, ""))));
   [%expect
     {|
 x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x \
  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x  x
 |}]
 
-let pp_pair ppf (a,b) = Format.fprintf ppf "(%i,@ %i)" a b
+let pp_pair ppf (a, b) = Format.fprintf ppf "(%i,@ %i)" a b
 
 let%expect_test _ =
-  print (
-    Pp.text "hello" ++ Pp.newline ++
-    Pp.vbox (Pp.of_fmt pp_pair (1,2)) ++ Pp.space ++ Pp.text "foo"
-  );
-  [%expect{|
+  print
+    (Pp.text "hello" ++ Pp.newline
+    ++ Pp.vbox (Pp.of_fmt pp_pair (1, 2))
+    ++ Pp.space ++ Pp.text "foo");
+  [%expect {|
     hello
     (1,
     2)