diff --git a/CHANGES.md b/CHANGES.md
index 94a19b7f..ff40288c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,10 @@
+next
+----
+
+- Add a `(universe)` special dependency to specify that an action
+  depend on everything in the universe. Jbuilder cannot cache the
+  result of an action that depend on the universe (#603, fixes #255)
+
 1.0+beta19 (13/03/2018)
 -----------------------
 
diff --git a/doc/jbuild.rst b/doc/jbuild.rst
index e3974c42..0f43a835 100644
--- a/doc/jbuild.rst
+++ b/doc/jbuild.rst
@@ -1052,6 +1052,12 @@ syntax:
   :ref:`glob <glob>` for details
 - ``(files_recursively_in <dir>)``: depend on all files in the subtree with root
   ``<dir>``
+- ``(universe)``: depend on everything in the universe. This is for
+  cases where dependencies are too hard to specify. Note that Jbuilder
+  will not be able to cache the result of actions that depend on the
+  universe. In any case, this is only for dependencies in the
+  installed world, you must still specify all dependencies that come
+  from the workspace.
 
 In all these cases, the argument supports `Variables expansion`_.
 
diff --git a/src/build_system.ml b/src/build_system.ml
index f10d0660..ac56495a 100644
--- a/src/build_system.ml
+++ b/src/build_system.ml
@@ -339,7 +339,8 @@ type t =
   ; file_tree   : File_tree.t
   ; mutable local_mkdirs : Path.Local.Set.t
   ; mutable dirs : (Path.t, Dir_status.t) Hashtbl.t
-  ; mutable gen_rules : (dir:Path.t -> string list -> extra_sub_directories_to_keep) String_map.t
+  ; mutable gen_rules :
+      (dir:Path.t -> string list -> extra_sub_directories_to_keep) String_map.t
   ; mutable load_dir_stack : Path.t list
   ; (* Set of directories under _build that have at least one rule and
        all their ancestors. *)
@@ -1173,8 +1174,24 @@ let eval_request t ~request ~process_target =
        let dyn_deps = Build_exec.exec_nop t request () in
        process_targets (Pset.diff dyn_deps static_deps))
 
+let universe_file = Path.relative Path.build_dir ".universe-state"
+
+let update_universe t =
+  (* To workaround the fact that [mtime] is not precise enough on OSX *)
+  Utils.Cached_digest.remove universe_file;
+  let fname = Path.to_string universe_file in
+  let n =
+    if Sys.file_exists fname then
+      Sexp.Of_sexp.int (Sexp.load ~mode:Single ~fname) + 1
+    else
+      0
+  in
+  make_local_dirs t (Pset.singleton Path.build_dir);
+  Io.write_file fname (Sexp.to_string (Sexp.To_sexp.int n))
+
 let do_build t ~request =
   entry_point t ~f:(fun () ->
+    update_universe t;
     eval_request t ~request ~process_target:(wait_for_file t))
 
 module Ir_set = Set.Make(Internal_rule)
diff --git a/src/build_system.mli b/src/build_system.mli
index 6b21b057..b10a10fc 100644
--- a/src/build_system.mli
+++ b/src/build_system.mli
@@ -159,6 +159,9 @@ val do_build
 
 (** {2 Other queries} *)
 
+(** File for the [(universe)] dependency. *)
+val universe_file : Path.t
+
 val is_target : t -> Path.t -> bool
 
 (** Return all the library dependencies (as written by the user)
diff --git a/src/jbuild.ml b/src/jbuild.ml
index 43bdbb8b..3afc2053 100644
--- a/src/jbuild.ml
+++ b/src/jbuild.ml
@@ -230,18 +230,20 @@ module Dep_conf = struct
     | Alias_rec of String_with_vars.t
     | Glob_files of String_with_vars.t
     | Files_recursively_in of String_with_vars.t
+    | Universe
 
   let t =
     let t =
-      let cstr name f =
+      let cstr_sw name f =
         cstr name (String_with_vars.t @> nil) f
       in
       sum
-        [ cstr "file"                 (fun x -> File x)
-        ; cstr "alias"                (fun x -> Alias x)
-        ; cstr "alias_rec"            (fun x -> Alias_rec x)
-        ; cstr "glob_files"           (fun x -> Glob_files x)
-        ; cstr "files_recursively_in" (fun x -> Files_recursively_in x)
+        [ cstr_sw "file"                 (fun x -> File x)
+        ; cstr_sw "alias"                (fun x -> Alias x)
+        ; cstr_sw "alias_rec"            (fun x -> Alias_rec x)
+        ; cstr_sw "glob_files"           (fun x -> Glob_files x)
+        ; cstr_sw "files_recursively_in" (fun x -> Files_recursively_in x)
+        ; cstr    "universe" nil         Universe
         ]
     in
     fun sexp ->
@@ -264,6 +266,8 @@ module Dep_conf = struct
     | Files_recursively_in t ->
        List [Sexp.unsafe_atom_of_string "files_recursively_in" ;
              String_with_vars.sexp_of_t t]
+    | Universe ->
+      Sexp.unsafe_atom_of_string "universe"
 end
 
 module Preprocess = struct
diff --git a/src/jbuild.mli b/src/jbuild.mli
index c3fdfa58..05a989b2 100644
--- a/src/jbuild.mli
+++ b/src/jbuild.mli
@@ -125,6 +125,7 @@ module Dep_conf : sig
     | Alias_rec of String_with_vars.t
     | Glob_files of String_with_vars.t
     | Files_recursively_in of String_with_vars.t
+    | Universe
 
   val t : t Sexp.Of_sexp.t
   val sexp_of_t : t -> Sexp.t
diff --git a/src/super_context.ml b/src/super_context.ml
index 8bb6f1ce..ca13e310 100644
--- a/src/super_context.ml
+++ b/src/super_context.ml
@@ -338,6 +338,9 @@ module Deps = struct
       let path = Path.relative dir (expand_vars t ~scope ~dir s) in
       Build.files_recursively_in ~dir:path ~file_tree:t.file_tree
       >>^ Pset.to_list
+    | Universe ->
+      Build.path Build_system.universe_file
+      >>^ fun () -> []
 
   let interpret t ~scope ~dir l =
     Build.all (List.map l ~f:(dep t ~scope ~dir))
diff --git a/test/blackbox-tests/jbuild b/test/blackbox-tests/jbuild
index 727f140d..4d3f6294 100644
--- a/test/blackbox-tests/jbuild
+++ b/test/blackbox-tests/jbuild
@@ -430,3 +430,13 @@
      (progn
       (run ${exe:cram.exe} run.t)
       (diff? run.t run.t.corrected)))))))
+
+(alias
+ ((name runtest)
+  (deps ((files_recursively_in test-cases/depend-on-the-universe)))
+  (action
+   (chdir test-cases/depend-on-the-universe
+    (setenv JBUILDER ${bin:jbuilder}
+     (progn
+      (run ${exe:cram.exe} run.t)
+      (diff? run.t run.t.corrected)))))))
diff --git a/test/blackbox-tests/test-cases/depend-on-the-universe/jbuild b/test/blackbox-tests/test-cases/depend-on-the-universe/jbuild
new file mode 100644
index 00000000..7669794b
--- /dev/null
+++ b/test/blackbox-tests/test-cases/depend-on-the-universe/jbuild
@@ -0,0 +1,4 @@
+(alias
+ ((name x)
+  (deps ((universe)))
+  (action (echo "Hello, world!"))))
diff --git a/test/blackbox-tests/test-cases/depend-on-the-universe/run.t b/test/blackbox-tests/test-cases/depend-on-the-universe/run.t
new file mode 100644
index 00000000..3b51b455
--- /dev/null
+++ b/test/blackbox-tests/test-cases/depend-on-the-universe/run.t
@@ -0,0 +1,10 @@
+  $ $JBUILDER build --root . -j 1 --display quiet @x
+  Hello, world!
+  $ $JBUILDER build --root . -j 1 --display quiet @x
+  Hello, world!
+  $ $JBUILDER build --root . -j 1 --display quiet @x
+  Hello, world!
+  $ $JBUILDER build --root . -j 1 --display quiet @x
+  Hello, world!
+  $ $JBUILDER build --root . -j 1 --display quiet @x
+  Hello, world!