diff --git a/lib/Fmt_ast.ml b/lib/Fmt_ast.ml
index 7eac0d0871..69a04c1db3 100644
--- a/lib/Fmt_ast.ml
+++ b/lib/Fmt_ast.ml
@@ -783,7 +783,7 @@ and fmt_modals ?(pro = fmt "@ ") c ~ats modals =
   let fmt_ats =
     match ats with `Zero -> str "" | `One -> str "@ " | `Two -> str "@@ "
   in
-  let fmt_modal {txt; loc} = Cmts.fmt c loc (str txt) in
+  let fmt_modal {txt; loc} = Cmts.fmt c loc (str txt) ~eol:(fmt "@ ") in
   let fmt_mode {txt= Mode mode; loc} = fmt_modal {txt= mode; loc} in
   let fmt_modality {txt= Modality modality; loc} =
     fmt_modal {txt= modality; loc}
@@ -5302,7 +5302,7 @@ let fmt_file (type a) ~ctx ~fmt_code ~debug (fragment : a Extended_ast.t)
   let c = {source; cmts; conf; debug; fmt_code} in
   match (fragment, itms) with
   | Signature, {psg_items= []; psg_modalities; _} ->
-      fmt_modals c ~ats:`Two (Modalities psg_modalities)
+      fmt_modals ~pro:noop c ~ats:`Two (Modalities psg_modalities)
       $ Cmts.fmt_after ~pro:noop c Location.none
   | Structure, [] | Use_file, [] -> Cmts.fmt_after ~pro:noop c Location.none
   | Structure, l -> Chunk.split_and_fmt Structure c ctx l
diff --git a/test/passing/dune.inc b/test/passing/dune.inc
index 3fbbe502f8..3b7d925dd4 100644
--- a/test/passing/dune.inc
+++ b/test/passing/dune.inc
@@ -8563,6 +8563,80 @@
  (package ocamlformat)
  (action (diff tests/mod_type_subst.ml.js-err mod_type_subst.ml.js-stderr)))
 
+(rule
+ (deps tests/.ocamlformat )
+ (package ocamlformat)
+ (action
+  (with-stdout-to modality_comments_failure.mli.stdout
+   (with-stderr-to modality_comments_failure.mli.stderr
+     (with-accepted-exit-codes 1
+       (run %{bin:ocamlformat} --margin-check %{dep:tests/modality_comments_failure.mli}))))))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_failure.mli.ref modality_comments_failure.mli.stdout)))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_failure.mli.err modality_comments_failure.mli.stderr)))
+
+(rule
+ (deps tests/.ocamlformat )
+ (package ocamlformat)
+ (action
+  (with-stdout-to modality_comments_failure.mli.js-stdout
+   (with-stderr-to modality_comments_failure.mli.js-stderr
+     (with-accepted-exit-codes 1
+       (run %{bin:ocamlformat} --profile=janestreet --enable-outside-detected-project --disable-conf-files %{dep:tests/modality_comments_failure.mli}))))))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_failure.mli.js-ref modality_comments_failure.mli.js-stdout)))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_failure.mli.js-err modality_comments_failure.mli.js-stderr)))
+
+(rule
+ (deps tests/.ocamlformat )
+ (package ocamlformat)
+ (action
+  (with-stdout-to modality_comments_regression.mli.stdout
+   (with-stderr-to modality_comments_regression.mli.stderr
+     (run %{bin:ocamlformat} --margin-check %{dep:tests/modality_comments_regression.mli})))))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_regression.mli.ref modality_comments_regression.mli.stdout)))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_regression.mli.err modality_comments_regression.mli.stderr)))
+
+(rule
+ (deps tests/.ocamlformat )
+ (package ocamlformat)
+ (action
+  (with-stdout-to modality_comments_regression.mli.js-stdout
+   (with-stderr-to modality_comments_regression.mli.js-stderr
+     (run %{bin:ocamlformat} --profile=janestreet --enable-outside-detected-project --disable-conf-files %{dep:tests/modality_comments_regression.mli})))))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_regression.mli.js-ref modality_comments_regression.mli.js-stdout)))
+
+(rule
+ (alias runtest)
+ (package ocamlformat)
+ (action (diff tests/modality_comments_regression.mli.js-err modality_comments_regression.mli.js-stderr)))
+
 (rule
  (deps tests/.ocamlformat )
  (package ocamlformat)
diff --git a/test/passing/tests/default_modalities2.mli.js-ref b/test/passing/tests/default_modalities2.mli.js-ref
index f4da7957cc..56160f153e 100644
--- a/test/passing/tests/default_modalities2.mli.js-ref
+++ b/test/passing/tests/default_modalities2.mli.js-ref
@@ -1,7 +1,6 @@
 @@ (* a *)
 
-   (* b *)
-   moda1 (* c *) moda2
+   (* b *) moda1 (* c *) moda2
 
 (* d *)
 val x : int
diff --git a/test/passing/tests/default_modalities2.mli.ref b/test/passing/tests/default_modalities2.mli.ref
index f4da7957cc..56160f153e 100644
--- a/test/passing/tests/default_modalities2.mli.ref
+++ b/test/passing/tests/default_modalities2.mli.ref
@@ -1,7 +1,6 @@
 @@ (* a *)
 
-   (* b *)
-   moda1 (* c *) moda2
+   (* b *) moda1 (* c *) moda2
 
 (* d *)
 val x : int
diff --git a/test/passing/tests/layout_abbreviation-erased.ml.js-ref b/test/passing/tests/layout_abbreviation-erased.ml.js-ref
index 662ee36e92..f099198d4f 100644
--- a/test/passing/tests/layout_abbreviation-erased.ml.js-ref
+++ b/test/passing/tests/layout_abbreviation-erased.ml.js-ref
@@ -815,7 +815,11 @@ kind_abbrev_ k =
   (* 375 *)
   mod
      (* 382 *)
-     m (* 381 *) mmmmmmmmmmmmmmmmmmmmm (* 383 *) mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
+     m
+     (* 381 *)
+     mmmmmmmmmmmmmmmmmmmmm
+     (* 383 *)
+     mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
 (* 374 *)
 
 kind_abbrev_ k =
@@ -1912,8 +1916,8 @@ module type S = sig
                                       _
                                       (* 1192 *)
                                       (* 1191 *)
-                                      mod (* 1194 *)
-                                          mmmmmmmmmmmmm (* 1195 *) mmmmmmmmmmmmm
+                                      mod
+                                         (* 1194 *) mmmmmmmmmmmmm (* 1195 *) mmmmmmmmmmmmm
                                       (* 1190 *)
                                       (* 1189 *)
                                       with (* 1196 *) tt (* 1188 *))
diff --git a/test/passing/tests/layout_abbreviation.ml.err b/test/passing/tests/layout_abbreviation.ml.err
index a32acaee89..72d82581af 100644
--- a/test/passing/tests/layout_abbreviation.ml.err
+++ b/test/passing/tests/layout_abbreviation.ml.err
@@ -1,12 +1,12 @@
 Warning: tests/layout_abbreviation.ml:2044 exceeds the margin
 Warning: tests/layout_abbreviation.ml:2058 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2090 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2105 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2122 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2139 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2141 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2187 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2194 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2266 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2268 exceeds the margin
-Warning: tests/layout_abbreviation.ml:2277 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2089 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2104 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2121 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2138 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2140 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2186 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2193 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2265 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2267 exceeds the margin
+Warning: tests/layout_abbreviation.ml:2276 exceeds the margin
diff --git a/test/passing/tests/layout_abbreviation.ml.js-ref b/test/passing/tests/layout_abbreviation.ml.js-ref
index 662ee36e92..f099198d4f 100644
--- a/test/passing/tests/layout_abbreviation.ml.js-ref
+++ b/test/passing/tests/layout_abbreviation.ml.js-ref
@@ -815,7 +815,11 @@ kind_abbrev_ k =
   (* 375 *)
   mod
      (* 382 *)
-     m (* 381 *) mmmmmmmmmmmmmmmmmmmmm (* 383 *) mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
+     m
+     (* 381 *)
+     mmmmmmmmmmmmmmmmmmmmm
+     (* 383 *)
+     mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
 (* 374 *)
 
 kind_abbrev_ k =
@@ -1912,8 +1916,8 @@ module type S = sig
                                       _
                                       (* 1192 *)
                                       (* 1191 *)
-                                      mod (* 1194 *)
-                                          mmmmmmmmmmmmm (* 1195 *) mmmmmmmmmmmmm
+                                      mod
+                                         (* 1194 *) mmmmmmmmmmmmm (* 1195 *) mmmmmmmmmmmmm
                                       (* 1190 *)
                                       (* 1189 *)
                                       with (* 1196 *) tt (* 1188 *))
diff --git a/test/passing/tests/layout_abbreviation.ml.ref b/test/passing/tests/layout_abbreviation.ml.ref
index c95201d25d..ae279dadd6 100644
--- a/test/passing/tests/layout_abbreviation.ml.ref
+++ b/test/passing/tests/layout_abbreviation.ml.ref
@@ -2066,8 +2066,7 @@ module type S = sig
                                                     tttttttttttttttttttt
                                                     (* 1091 *)
                                                     (* 1079 *)))
-                                           mod (* 1096 *)
-                                               mmmmmmmmmmmmmm
+                                           mod (* 1096 *) mmmmmmmmmmmmmm
                                            (* 1078 *)
                                            (* 1077 *)
                                            with (* 1097 *)
diff --git a/test/passing/tests/layout_annotation_mod.ml.js-ref b/test/passing/tests/layout_annotation_mod.ml.js-ref
index 8d70bbfe77..15ebcd0a13 100644
--- a/test/passing/tests/layout_annotation_mod.ml.js-ref
+++ b/test/passing/tests/layout_annotation_mod.ml.js-ref
@@ -240,8 +240,7 @@ type a =
   ((* comment 1 *)
   'k (* comment 2 *) :
   (* comment 3 *)
-  immediate64 (* comment 4 *) mod (* comment 5 *)
-                                  mode (* comment 6 *))
+  immediate64 (* comment 4 *) mod (* comment 5 *) mode (* comment 6 *))
 (* comment 7 *)
 
 let f (type a : immediate mod mode) x = x
diff --git a/test/passing/tests/layout_annotation_mod.ml.ref b/test/passing/tests/layout_annotation_mod.ml.ref
index 836e461b9b..ee669bc9f2 100644
--- a/test/passing/tests/layout_annotation_mod.ml.ref
+++ b/test/passing/tests/layout_annotation_mod.ml.ref
@@ -310,8 +310,7 @@ type a =
   (* comment 3 *)
   immediate64
   (* comment 4 *)
-  mod (* comment 5 *)
-      mode
+  mod (* comment 5 *) mode
   (* comment 6 *))
 (* comment 7 *)
 
diff --git a/test/passing/tests/modality_comments_failure.mli b/test/passing/tests/modality_comments_failure.mli
new file mode 100644
index 0000000000..e6b7dd02e8
--- /dev/null
+++ b/test/passing/tests/modality_comments_failure.mli
@@ -0,0 +1,5 @@
+(** a *)
+
+(** b *)
+
+@@ a b c
diff --git a/test/passing/tests/modality_comments_failure.mli.err b/test/passing/tests/modality_comments_failure.mli.err
new file mode 100644
index 0000000000..62640188a9
--- /dev/null
+++ b/test/passing/tests/modality_comments_failure.mli.err
@@ -0,0 +1,6 @@
+ocamlformat: ignoring "tests/modality_comments_failure.mli" (misplaced documentation comments - warning 50)
+File "tests/modality_comments_failure.mli", line 3, characters 0-8:
+3 | (** b *)
+    ^^^^^^^^
+Warning 50 [unexpected-docstring]: unattached documentation comment (ignored)
+Hint: (Warning 50) This file contains a documentation comment (** ... *) that the OCaml compiler does not know how to attach to the AST. OCamlformat does not support these cases. You can find more information at: https://github.com/ocaml-ppx/ocamlformat#overview. If you'd like to disable this check and let ocamlformat make a choice (though it might not be consistent with the ocaml compilers and odoc), you can set the --no-comment-check option.
diff --git a/test/passing/tests/modality_comments_failure.mli.js-err b/test/passing/tests/modality_comments_failure.mli.js-err
new file mode 100644
index 0000000000..62640188a9
--- /dev/null
+++ b/test/passing/tests/modality_comments_failure.mli.js-err
@@ -0,0 +1,6 @@
+ocamlformat: ignoring "tests/modality_comments_failure.mli" (misplaced documentation comments - warning 50)
+File "tests/modality_comments_failure.mli", line 3, characters 0-8:
+3 | (** b *)
+    ^^^^^^^^
+Warning 50 [unexpected-docstring]: unattached documentation comment (ignored)
+Hint: (Warning 50) This file contains a documentation comment (** ... *) that the OCaml compiler does not know how to attach to the AST. OCamlformat does not support these cases. You can find more information at: https://github.com/ocaml-ppx/ocamlformat#overview. If you'd like to disable this check and let ocamlformat make a choice (though it might not be consistent with the ocaml compilers and odoc), you can set the --no-comment-check option.
diff --git a/test/passing/tests/modality_comments_failure.mli.js-ref b/test/passing/tests/modality_comments_failure.mli.js-ref
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/passing/tests/modality_comments_failure.mli.ref b/test/passing/tests/modality_comments_failure.mli.ref
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/passing/tests/modality_comments_failure.mli.should-fail b/test/passing/tests/modality_comments_failure.mli.should-fail
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/test/passing/tests/modality_comments_regression.mli b/test/passing/tests/modality_comments_regression.mli
new file mode 100644
index 0000000000..314fa8c49f
--- /dev/null
+++ b/test/passing/tests/modality_comments_regression.mli
@@ -0,0 +1,3 @@
+@@ mmmmmmmmm m (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*) mmmmmmmmmm mmmmmmmmmm mmmmm mm m
+
+val command : Command.t  @@ mmmmmmmm m mmmmm mmm mmmmmmmm (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*) mmmmmmm mmmmm mmmmmm
diff --git a/test/passing/tests/modality_comments_regression.mli.js-ref b/test/passing/tests/modality_comments_regression.mli.js-ref
new file mode 100644
index 0000000000..b1946c89f3
--- /dev/null
+++ b/test/passing/tests/modality_comments_regression.mli.js-ref
@@ -0,0 +1,20 @@
+@@ m
+   m
+   mm
+   mmmmm
+   mmmmmmmmm
+   (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*)
+   mmmmmmmmmm
+   mmmmmmmmmm
+
+val command
+  : Command.t
+  @@ m
+     mmm
+     mmmmm
+     mmmmm
+     mmmmmm
+     (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*)
+     mmmmmmm
+     mmmmmmmm
+     mmmmmmmm
diff --git a/test/passing/tests/modality_comments_regression.mli.ref b/test/passing/tests/modality_comments_regression.mli.ref
new file mode 100644
index 0000000000..7e999382ae
--- /dev/null
+++ b/test/passing/tests/modality_comments_regression.mli.ref
@@ -0,0 +1,19 @@
+@@ m
+   m
+   mm
+   mmmmm
+   mmmmmmmmm
+   (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*)
+   mmmmmmmmmm
+   mmmmmmmmmm
+
+val command : Command.t
+  @@ m
+     mmm
+     mmmmm
+     mmmmm
+     mmmmmm
+     (* xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*)
+     mmmmmmm
+     mmmmmmmm
+     mmmmmmmm