diff --git a/src/lib_protocol_compiler/main_embedded_packer.ml b/src/lib_protocol_compiler/main_embedded_packer.ml
index 80adbe051..1eaf329a5 100644
--- a/src/lib_protocol_compiler/main_embedded_packer.ml
+++ b/src/lib_protocol_compiler/main_embedded_packer.ml
@@ -31,7 +31,7 @@ end
 let () =
   Format.printf {|
 let () =
-  let module Ignored = Tezos_protocol_updater.Registered_protocol.Register
+  let module Ignored = Tezos_protocol_updater.Registered_protocol.Register_embedded
     (Tezos_embedded_protocol_environment_%s.Environment)
     (Tezos_embedded_raw_protocol_%s.Main)
     (Source) in
diff --git a/src/lib_protocol_updater/registered_protocol.ml b/src/lib_protocol_updater/registered_protocol.ml
index 5abb6d0c5..e0f9e0a92 100644
--- a/src/lib_protocol_updater/registered_protocol.ml
+++ b/src/lib_protocol_updater/registered_protocol.ml
@@ -42,6 +42,9 @@ module VersionTable = Protocol_hash.Table
 let versions : (module T) VersionTable.t =
   VersionTable.create 20
 
+let sources : Protocol.t VersionTable.t =
+  VersionTable.create 20
+
 let mem hash =
   VersionTable.mem versions hash ||
   Tezos_protocol_registerer.Registerer.mem hash
@@ -57,7 +60,17 @@ let get hash =
   try Some (get_exn hash)
   with Not_found -> None
 
-module Register
+let list_embedded () =
+  VersionTable.fold (fun k _ acc -> k :: acc) sources []
+
+let get_embedded_sources_exn hash =
+  VersionTable.find sources hash
+
+let get_embedded_sources hash =
+  try Some (get_embedded_sources_exn hash)
+  with Not_found -> None
+
+module Register_embedded
     (Env : Tezos_protocol_environment_shell.V1)
     (Proto : Env.Updater.PROTOCOL)
     (Source : sig
@@ -73,7 +86,8 @@ module Register
     let module Name = struct
       let name = Protocol_hash.to_b58check hash
     end in
-    (* TODO add a memory table for "embedded" sources... *)
+    VersionTable.add
+      sources hash Source.sources ;
     VersionTable.add
       versions hash
       (module struct
diff --git a/src/lib_protocol_updater/registered_protocol.mli b/src/lib_protocol_updater/registered_protocol.mli
index 1905765fe..fa6765e75 100644
--- a/src/lib_protocol_updater/registered_protocol.mli
+++ b/src/lib_protocol_updater/registered_protocol.mli
@@ -25,8 +25,12 @@ val mem: Protocol_hash.t -> bool
 val get: Protocol_hash.t -> t option
 val get_exn: Protocol_hash.t -> t
 
+val list_embedded: unit -> Protocol_hash.t list
 
-module Register
+val get_embedded_sources: Protocol_hash.t -> Protocol.t option
+val get_embedded_sources_exn: Protocol_hash.t -> Protocol.t
+
+module Register_embedded
     (Env : Tezos_protocol_environment_shell.V1)
     (Proto : Env.Updater.PROTOCOL)
     (Source : sig
diff --git a/src/lib_shell/protocol_directory.ml b/src/lib_shell/protocol_directory.ml
index 0aff34ced..54a67de02 100644
--- a/src/lib_shell/protocol_directory.ml
+++ b/src/lib_shell/protocol_directory.ml
@@ -17,12 +17,16 @@ let build_rpc_directory state =
 
   gen_register0 Protocol_services.S.list begin fun () () ->
     State.Protocol.list state >>= fun set ->
-    let protocols = Protocol_hash.Set.elements set in
+    let protocols =
+      Protocol_hash.Set.elements set @
+      Registered_protocol.list_embedded () in
     RPC_answer.return protocols
   end ;
 
   register1 Protocol_services.S.contents begin fun hash () () ->
-    State.Protocol.read state hash
+    match Registered_protocol.get_embedded_sources hash with
+    | Some p -> return p
+    | None -> State.Protocol.read state hash
   end ;
 
   !dir