diff --git a/ocaml/xapi-idl/lib/observer_helpers.mli b/ocaml/xapi-idl/lib/observer_helpers.mli
new file mode 100644
index 0000000000..34a4688d00
--- /dev/null
+++ b/ocaml/xapi-idl/lib/observer_helpers.mli
@@ -0,0 +1,226 @@
+val queue_name : string
+
+val default_path : string
+
+module Errors : sig
+  type error =
+    | Internal_error of string
+    | Unimplemented of string
+    | Unknown_error
+
+  val typ_of_error : error Rpc.Types.typ
+
+  val error : error Rpc.Types.def
+end
+
+exception Observer_error of Errors.error
+
+type debug_info = string
+
+(** ObserverAPI contains the declarations for the RPCs which are sent to
+    Observer modules when the corresponding function is called on the Observer
+    see ocaml/libs/tracing/ and ocaml/xapi/xapi_observer.ml *)
+module ObserverAPI : functor (R : Idl.RPC) -> sig
+  val description : Idl.Interface.description
+
+  val implementation : R.implementation
+
+  val create :
+    (   debug_info
+     -> string
+     -> string
+     -> (string * string) list
+     -> string list
+     -> bool
+     -> (unit, Errors.error) R.comp
+    )
+    R.res
+  (** [create dbg uuid name attributes endpoints enabled] is for when the
+      Observer is created. [uuid] is the Observer which has been created and
+      the parameters following are the fields the Observer was created with. *)
+
+  val destroy : (debug_info -> string -> (unit, Errors.error) R.comp) R.res
+  (** [destroy dbg uuid] is for when the Observer is destroyed. [uuid]
+      is the Observer which has been destroyed.*)
+
+  val set_enabled :
+    (debug_info -> string -> bool -> (unit, Errors.error) R.comp) R.res
+  (** [set_enabled dbg uuid enabled] is for when the Observer's enabled
+      field is set to [enabled]. *)
+
+  val set_attributes :
+    (   debug_info
+     -> string
+     -> (string * string) list
+     -> (unit, Errors.error) R.comp
+    )
+    R.res
+  (** [set_attributes dbg uuid attributes] is for when the Observer's
+      attributes field is set to [attributes]. *)
+
+  val set_endpoints :
+    (debug_info -> string -> string list -> (unit, Errors.error) R.comp) R.res
+  (** [set_endpoints dbg uuid endpoints] is for when the Observer's endpoints
+      field is set to [endpoints]. *)
+
+  val init : (debug_info -> (unit, Errors.error) R.comp) R.res
+  (** [init dbg] is for when tracing is first initialised *)
+
+  val set_trace_log_dir :
+    (debug_info -> string -> (unit, Errors.error) R.comp) R.res
+  (** [set_trace_log_dir dbg dir] is for when the destination of the
+      trace logs is set to [dir]. *)
+
+  val set_export_interval :
+    (debug_info -> float -> (unit, Errors.error) R.comp) R.res
+  (** [set_export_interval dbg interval] is for when the interval between trace
+      exports is set to [interval]. *)
+
+  val set_max_spans : (debug_info -> int -> (unit, Errors.error) R.comp) R.res
+  (** [set_max_spans dbg spans] is for when the max number of spans is
+      set to [spans]. *)
+
+  val set_max_traces : (debug_info -> int -> (unit, Errors.error) R.comp) R.res
+  (** [set_max_traces dbg traces] is for when the max number of traces is
+      set to [traces]. *)
+
+  val set_max_file_size :
+    (debug_info -> int -> (unit, Errors.error) R.comp) R.res
+  (** [set_max_file_size dbg file_size] is for when the max size of a trace file
+      is set to [file_size]. *)
+
+  val set_host_id : (debug_info -> string -> (unit, Errors.error) R.comp) R.res
+  (** [set_host_id dbg host_id] is for when the host to be traced is
+      set to [host_id]. *)
+
+  val set_compress_tracing_files :
+    (debug_info -> bool -> (unit, Errors.error) R.comp) R.res
+  (** [set_compress_tracing_files dbg enabled] is for when the compression of
+      tracing files is enabled/disabled according to [enabled]. *)
+end
+
+(** A Server_impl module will define how the Server responds to ObserverAPI calls *)
+module type Server_impl = sig
+  type context = unit
+
+  val create :
+       context
+    -> dbg:debug_info
+    -> uuid:string
+    -> name_label:string
+    -> attributes:(string * string) list
+    -> endpoints:string list
+    -> enabled:bool
+    -> unit
+
+  val destroy : context -> dbg:debug_info -> uuid:string -> unit
+
+  val set_enabled :
+    context -> dbg:debug_info -> uuid:string -> enabled:bool -> unit
+
+  val set_attributes :
+       context
+    -> dbg:debug_info
+    -> uuid:string
+    -> attributes:(string * string) list
+    -> unit
+
+  val set_endpoints :
+    context -> dbg:debug_info -> uuid:string -> endpoints:string list -> unit
+
+  val init : context -> dbg:debug_info -> unit
+
+  val set_trace_log_dir : context -> dbg:debug_info -> dir:string -> unit
+
+  val set_export_interval : context -> dbg:debug_info -> interval:float -> unit
+
+  val set_max_spans : context -> dbg:debug_info -> spans:int -> unit
+
+  val set_max_traces : context -> dbg:debug_info -> traces:int -> unit
+
+  val set_max_file_size : context -> dbg:debug_info -> file_size:int -> unit
+
+  val set_host_id : context -> dbg:debug_info -> host_id:string -> unit
+
+  val set_compress_tracing_files :
+    context -> dbg:debug_info -> enabled:bool -> unit
+end
+
+(** A Server for receiving ObserverAPI calls *)
+module Server : functor (_ : Server_impl) () -> sig
+  module S : sig
+    val create :
+         (   debug_info
+          -> string
+          -> string
+          -> (string * string) list
+          -> string list
+          -> bool
+          -> unit
+         )
+      -> unit
+
+    val destroy : (debug_info -> string -> unit) -> unit
+
+    val set_enabled : (debug_info -> string -> bool -> unit) -> unit
+
+    val set_attributes :
+      (debug_info -> string -> (string * string) list -> unit) -> unit
+
+    val set_endpoints : (debug_info -> string -> string list -> unit) -> unit
+
+    val init : (debug_info -> unit) -> unit
+
+    val set_trace_log_dir : (debug_info -> string -> unit) -> unit
+
+    val set_export_interval : (debug_info -> float -> unit) -> unit
+
+    val set_max_spans : (debug_info -> int -> unit) -> unit
+
+    val set_max_traces : (debug_info -> int -> unit) -> unit
+
+    val set_max_file_size : (debug_info -> int -> unit) -> unit
+
+    val set_host_id : (debug_info -> string -> unit) -> unit
+
+    val set_compress_tracing_files : (debug_info -> bool -> unit) -> unit
+  end
+
+  val process : Rpc.call -> Rpc.response
+end
+
+(** A client for sending ObserverAPI calls to the above queue_name *)
+module Client : sig
+  val create :
+       debug_info
+    -> string
+    -> string
+    -> (string * string) list
+    -> string list
+    -> bool
+    -> unit
+
+  val destroy : debug_info -> string -> unit
+
+  val set_enabled : debug_info -> string -> bool -> unit
+
+  val set_attributes : debug_info -> string -> (string * string) list -> unit
+
+  val set_endpoints : debug_info -> string -> string list -> unit
+
+  val init : debug_info -> unit
+
+  val set_trace_log_dir : debug_info -> string -> unit
+
+  val set_export_interval : debug_info -> float -> unit
+
+  val set_max_spans : debug_info -> int -> unit
+
+  val set_max_traces : debug_info -> int -> unit
+
+  val set_max_file_size : debug_info -> int -> unit
+
+  val set_host_id : debug_info -> string -> unit
+
+  val set_compress_tracing_files : debug_info -> bool -> unit
+end
diff --git a/ocaml/xapi-idl/lib/observer_skeleton.mli b/ocaml/xapi-idl/lib/observer_skeleton.mli
new file mode 100644
index 0000000000..c99b77f9a3
--- /dev/null
+++ b/ocaml/xapi-idl/lib/observer_skeleton.mli
@@ -0,0 +1,46 @@
+(** This module provides dummy implementations for each Observer function.
+    These are intended to be used to fill in the functions that the module will
+    not ever use, as they will raise an Unimplemented error if called *)
+module Observer : sig
+  type context = unit
+
+  val create :
+       context
+    -> dbg:string
+    -> uuid:string
+    -> name_label:string
+    -> attributes:(string * string) list
+    -> endpoints:string list
+    -> enabled:bool
+    -> unit
+
+  val destroy : context -> dbg:string -> uuid:string -> unit
+
+  val set_enabled : context -> dbg:string -> uuid:string -> enabled:bool -> unit
+
+  val set_attributes :
+       context
+    -> dbg:string
+    -> uuid:string
+    -> attributes:(string * string) list
+    -> unit
+
+  val set_endpoints :
+    context -> dbg:string -> uuid:string -> endpoints:string list -> unit
+
+  val init : context -> dbg:string -> unit
+
+  val set_trace_log_dir : context -> dbg:string -> dir:string -> unit
+
+  val set_export_interval : context -> dbg:string -> interval:float -> unit
+
+  val set_max_spans : context -> dbg:string -> spans:int -> unit
+
+  val set_max_traces : context -> dbg:string -> traces:int -> unit
+
+  val set_max_file_size : context -> dbg:string -> file_size:int -> unit
+
+  val set_host_id : context -> dbg:string -> host_id:string -> unit
+
+  val set_compress_tracing_files : context -> dbg:string -> enabled:bool -> unit
+end
diff --git a/quality-gate.sh b/quality-gate.sh
index 6455846d21..f6540cb2a1 100755
--- a/quality-gate.sh
+++ b/quality-gate.sh
@@ -25,7 +25,7 @@ verify-cert () {
 }
 
 mli-files () {
-  N=469
+  N=467
   X="ocaml/tests"
   X+="|ocaml/quicktest"
   X+="|ocaml/message-switch/core_test"