diff --git a/src/core/key_value.ml b/src/core/key_value.ml
index 6760c340..36ee087c 100644
--- a/src/core/key_value.ml
+++ b/src/core/key_value.ml
@@ -6,3 +6,6 @@ let conv (k, v) =
   let open Proto.Common in
   let value = Value.conv v in
   make_key_value ~key:k ?value ()
+
+let of_otel (kv : Proto.Common.key_value) : t =
+  kv.key, Value.of_otel_opt kv.value
diff --git a/src/core/opentelemetry.ml b/src/core/opentelemetry.ml
index ec84d0e4..73e34600 100644
--- a/src/core/opentelemetry.ml
+++ b/src/core/opentelemetry.ml
@@ -1,7 +1,5 @@
 (** Opentelemetry types and instrumentation *)
 
-open Common_
-
 module Rand_bytes = Rand_bytes
 (** Generation of random identifiers. *)
 
@@ -29,9 +27,6 @@ module Timestamp_ns = Timestamp_ns
 module Exporter = Exporter
 module Collector = Exporter [@@deprecated "Use 'Exporter' instead"]
 
-module Tick_callbacks = Tick_callbacks
-(** Helper to implement part of the exporter *)
-
 (** {2 Identifiers} *)
 
 module Trace_id = Trace_id
@@ -63,10 +58,6 @@ module Span_link = Span_link
 module Span_status = Span_status
 module Span_kind = Span_kind
 
-(** {2 Scopes} *)
-
-module Scope = Scope
-
 (** {2 Traces} *)
 
 module Span = Span
diff --git a/src/core/scope.ml b/src/core/scope.ml
deleted file mode 100644
index aa5cb19a..00000000
--- a/src/core/scope.ml
+++ /dev/null
@@ -1,131 +0,0 @@
-open Common_
-
-type item_list =
-  | Nil
-  | Ev of Event.t * item_list
-  | Attr of Key_value.t * item_list
-  | Span_link of Span_link.t * item_list
-  | Span_status of Span_status.t * item_list
-  | Span_kind of Span_kind.t * item_list
-
-type t = {
-  trace_id: Trace_id.t;
-  span_id: Span_id.t;
-  mutable items: item_list;
-}
-
-let attrs scope =
-  let rec loop acc = function
-    | Nil -> acc
-    | Attr (attr, l) -> loop (attr :: acc) l
-    | Ev (_, l) | Span_kind (_, l) | Span_link (_, l) | Span_status (_, l) ->
-      loop acc l
-  in
-  loop [] scope.items
-
-let events scope =
-  let rec loop acc = function
-    | Nil -> acc
-    | Ev (event, l) -> loop (event :: acc) l
-    | Attr (_, l) | Span_kind (_, l) | Span_link (_, l) | Span_status (_, l) ->
-      loop acc l
-  in
-  loop [] scope.items
-
-let links scope =
-  let rec loop acc = function
-    | Nil -> acc
-    | Span_link (span_link, l) -> loop (span_link :: acc) l
-    | Ev (_, l) | Span_kind (_, l) | Attr (_, l) | Span_status (_, l) ->
-      loop acc l
-  in
-  loop [] scope.items
-
-let status scope =
-  let rec loop = function
-    | Nil -> None
-    | Span_status (status, _) -> Some status
-    | Ev (_, l) | Attr (_, l) | Span_kind (_, l) | Span_link (_, l) -> loop l
-  in
-  loop scope.items
-
-let kind scope =
-  let rec loop = function
-    | Nil -> None
-    | Span_kind (k, _) -> Some k
-    | Ev (_, l) | Span_status (_, l) | Attr (_, l) | Span_link (_, l) -> loop l
-  in
-  loop scope.items
-
-let make ~trace_id ~span_id ?(events = []) ?(attrs = []) ?(links = []) ?status
-    () : t =
-  let items =
-    let items =
-      match status with
-      | None -> Nil
-      | Some status -> Span_status (status, Nil)
-    in
-    let items = List.fold_left (fun acc ev -> Ev (ev, acc)) items events in
-    let items = List.fold_left (fun acc attr -> Attr (attr, acc)) items attrs in
-    List.fold_left (fun acc link -> Span_link (link, acc)) items links
-  in
-  { trace_id; span_id; items }
-
-let[@inline] to_span_link ?trace_state ?attrs ?dropped_attributes_count
-    (self : t) : Span_link.t =
-  Span_link.make ?trace_state ?attrs ?dropped_attributes_count
-    ~trace_id:self.trace_id ~span_id:self.span_id ()
-
-let[@inline] to_span_ctx (self : t) : Span_ctx.t =
-  Span_ctx.make ~trace_id:self.trace_id ~parent_id:self.span_id ()
-
-open struct
-  let[@inline] is_not_dummy (self : t) : bool = Span_id.is_valid self.span_id
-end
-
-let[@inline] add_event (self : t) (ev : unit -> Event.t) : unit =
-  if is_not_dummy self then self.items <- Ev (ev (), self.items)
-
-let[@inline] record_exception (self : t) (exn : exn)
-    (bt : Printexc.raw_backtrace) : unit =
-  if is_not_dummy self then (
-    let ev =
-      Event.make "exception"
-        ~attrs:
-          [
-            "exception.message", `String (Printexc.to_string exn);
-            "exception.type", `String (Printexc.exn_slot_name exn);
-            ( "exception.stacktrace",
-              `String (Printexc.raw_backtrace_to_string bt) );
-          ]
-    in
-    self.items <- Ev (ev, self.items)
-  )
-
-let[@inline] add_attrs (self : t) (attrs : unit -> Key_value.t list) : unit =
-  if is_not_dummy self then
-    self.items <-
-      List.fold_left (fun acc attr -> Attr (attr, acc)) self.items (attrs ())
-
-let[@inline] add_links (self : t) (links : unit -> Span_link.t list) : unit =
-  if is_not_dummy self then
-    self.items <-
-      List.fold_left
-        (fun acc link -> Span_link (link, acc))
-        self.items (links ())
-
-let set_status (self : t) (status : Span_status.t) : unit =
-  if is_not_dummy self then self.items <- Span_status (status, self.items)
-
-let set_kind (self : t) (k : Span_kind.t) : unit =
-  if is_not_dummy self then self.items <- Span_kind (k, self.items)
-
-let ambient_scope_key : t Ambient_context.key = Ambient_context.create_key ()
-
-let get_ambient_scope ?scope () : t option =
-  match scope with
-  | Some _ -> scope
-  | None -> Ambient_context.get ambient_scope_key
-
-let[@inline] with_ambient_scope (sc : t) (f : unit -> 'a) : 'a =
-  Ambient_context.with_binding ambient_scope_key sc (fun _ -> f ())
diff --git a/src/core/scope.mli b/src/core/scope.mli
deleted file mode 100644
index 9ba60d0e..00000000
--- a/src/core/scope.mli
+++ /dev/null
@@ -1,89 +0,0 @@
-(** Scopes.
-
-    A scope is a trace ID and the span ID of the currently active span. *)
-
-open Common_
-
-type item_list
-
-type t = {
-  trace_id: Trace_id.t;
-  span_id: Span_id.t;
-  mutable items: item_list;
-}
-
-val attrs : t -> Key_value.t list
-
-val events : t -> Event.t list
-
-val links : t -> Span_link.t list
-
-val status : t -> Span_status.t option
-
-val kind : t -> Span_kind.t option
-
-val make :
-  trace_id:Trace_id.t ->
-  span_id:Span_id.t ->
-  ?events:Event.t list ->
-  ?attrs:Key_value.t list ->
-  ?links:Span_link.t list ->
-  ?status:Span_status.t ->
-  unit ->
-  t
-
-val to_span_link :
-  ?trace_state:string ->
-  ?attrs:Key_value.t list ->
-  ?dropped_attributes_count:int ->
-  t ->
-  Span_link.t
-(** Turn the scope into a span link *)
-
-val to_span_ctx : t -> Span_ctx.t
-(** Turn the scope into a span context *)
-
-val add_event : t -> (unit -> Event.t) -> unit
-(** Add an event to the scope. It will be aggregated into the span.
-
-    Note that this takes a function that produces an event, and will only call
-    it if there is an instrumentation backend. *)
-
-val record_exception : t -> exn -> Printexc.raw_backtrace -> unit
-
-val add_attrs : t -> (unit -> Key_value.t list) -> unit
-(** Add attributes to the scope. It will be aggregated into the span.
-
-    Note that this takes a function that produces attributes, and will only call
-    it if there is an instrumentation backend. *)
-
-val add_links : t -> (unit -> Span_link.t list) -> unit
-(** Add links to the scope. It will be aggregated into the span.
-
-    Note that this takes a function that produces links, and will only call it
-    if there is an instrumentation backend. *)
-
-val set_status : t -> Span_status.t -> unit
-(** set the span status.
-
-    Note that this function will be called only if there is an instrumentation
-    backend. *)
-
-val set_kind : t -> Span_kind.t -> unit
-(** Set the span's kind.
-    @since 0.11 *)
-
-val ambient_scope_key : t Ambient_context.key
-(** The opaque key necessary to access/set the ambient scope with
-    {!Ambient_context}. *)
-
-val get_ambient_scope : ?scope:t -> unit -> t option
-(** Obtain current scope from {!Ambient_context}, if available. *)
-
-val with_ambient_scope : t -> (unit -> 'a) -> 'a
-(** [with_ambient_scope sc thunk] calls [thunk()] in a context where [sc] is the
-    (thread|continuation)-local scope, then reverts to the previous local scope,
-    if any.
-
-    @see <https://github.com/ELLIOTTCABLE/ocaml-ambient-context>
-      ambient-context docs *)
diff --git a/src/core/span.ml b/src/core/span.ml
index 1ea8cb0b..f0135b40 100644
--- a/src/core/span.ml
+++ b/src/core/span.ml
@@ -22,11 +22,15 @@ type key_value =
     | `None
     ]
 
-let id self = Span_id.of_bytes self.span_id
+let[@inline] id self = Span_id.of_bytes self.span_id
 
-let create ?(kind = !Globals.default_span_kind) ?(id = Span_id.create ())
-    ?trace_state ?(attrs = []) ?(events = []) ?status ~trace_id ?parent
-    ?(links = []) ~start_time ~end_time name : t * id =
+let[@inline] trace_id self = Trace_id.of_bytes self.trace_id
+
+let[@inline] is_not_dummy self = Span_id.is_valid (id self)
+
+let make ?(kind = !Globals.default_span_kind) ?trace_state ?(attrs = [])
+    ?(events = []) ?status ~trace_id ~id ?parent ?(links = []) ~start_time
+    ~end_time name : t =
   let trace_id = Trace_id.to_bytes trace_id in
   let parent_span_id = Option.map Span_id.to_bytes parent in
   let attributes = List.map Key_value.conv attrs in
@@ -35,4 +39,85 @@ let create ?(kind = !Globals.default_span_kind) ?(id = Span_id.create ())
       ~attributes ~events ?trace_state ?status ~kind ~name ~links
       ~start_time_unix_nano:start_time ~end_time_unix_nano:end_time ()
   in
-  span, id
+  span
+
+let create_new ?kind ?(id = Span_id.create ()) ?trace_state ?attrs ?events
+    ?status ~trace_id ?parent ?links ~start_time ~end_time name : t =
+  make ?kind ~id ~trace_id ?trace_state ?attrs ?events ?status ?parent ?links
+    ~start_time ~end_time name
+
+let attrs self = self.attributes |> List.rev_map Key_value.of_otel
+
+let events self = self.events
+
+let links self : Span_link.t list = self.links
+
+let status self = self.status
+
+let kind self =
+  let k = self.kind in
+  if k = Span_kind_unspecified then
+    None
+  else
+    Some k
+
+let to_span_link (self : t) : Span_link.t =
+  make_span_link ~attributes:self.attributes
+    ?dropped_attributes_count:
+      (if span_has_dropped_attributes_count self then
+         Some self.dropped_attributes_count
+       else
+         None)
+    ?trace_state:
+      (if span_has_trace_state self then
+         Some self.trace_state
+       else
+         None)
+    ~trace_id:self.trace_id ~span_id:self.span_id ()
+
+let[@inline] to_span_ctx (self : t) : Span_ctx.t =
+  Span_ctx.make ~trace_id:(trace_id self) ~parent_id:(id self) ()
+
+let[@inline] add_event self ev : unit =
+  if is_not_dummy self then span_set_events self (ev :: self.events)
+
+let add_event' self ev : unit = if is_not_dummy self then add_event self (ev ())
+
+let record_exception (self : t) (exn : exn) (bt : Printexc.raw_backtrace) : unit
+    =
+  if is_not_dummy self then (
+    let ev =
+      Event.make "exception"
+        ~attrs:
+          [
+            "exception.message", `String (Printexc.to_string exn);
+            "exception.type", `String (Printexc.exn_slot_name exn);
+            ( "exception.stacktrace",
+              `String (Printexc.raw_backtrace_to_string bt) );
+          ]
+    in
+    add_event self ev
+  )
+
+let[@inline] add_attrs (self : t) (attrs : unit -> Key_value.t list) : unit =
+  if is_not_dummy self then (
+    let attrs = List.rev_map Key_value.conv (attrs ()) in
+    let attrs = List.rev_append attrs self.attributes in
+    span_set_attributes self attrs
+  )
+
+let add_links (self : t) (links : Span_link.t list) : unit =
+  if links <> [] then (
+    let links = List.rev_append links self.links in
+    span_set_links self links
+  )
+
+let add_links' (self : t) (links : unit -> Span_link.t list) : unit =
+  if is_not_dummy self then (
+    let links = List.rev_append (links ()) self.links in
+    span_set_links self links
+  )
+
+let set_status = span_set_status
+
+let set_kind = span_set_kind
diff --git a/src/core/span.mli b/src/core/span.mli
index cfb9a2de..673654a9 100644
--- a/src/core/span.mli
+++ b/src/core/span.mli
@@ -24,9 +24,30 @@ val id : t -> Span_id.t
 
 type key_value = Key_value.t
 
-val create :
+val make :
   ?kind:kind ->
-  ?id:id ->
+  ?trace_state:string ->
+  ?attrs:key_value list ->
+  ?events:Event.t list ->
+  ?status:status ->
+  trace_id:Trace_id.t ->
+  id:Span_id.t ->
+  ?parent:id ->
+  ?links:Span_link.t list ->
+  start_time:Timestamp_ns.t ->
+  end_time:Timestamp_ns.t ->
+  string ->
+  t
+(** [make ~trace_id ~id name] creates a new span
+    @param trace_id the trace this belongs to
+    @param parent parent span, if any
+    @param links
+      list of links to other spans, each with their trace state (see
+      {{:https://www.w3.org/TR/trace-context/#tracestate-header} w3.org}) *)
+
+val create_new :
+  ?kind:kind ->
+  ?id:Span_id.t ->
   ?trace_state:string ->
   ?attrs:key_value list ->
   ?events:Event.t list ->
@@ -37,10 +58,50 @@ val create :
   start_time:Timestamp_ns.t ->
   end_time:Timestamp_ns.t ->
   string ->
-  t * id
-(** [create ~trace_id name] creates a new span with its unique ID.
-    @param trace_id the trace this belongs to
-    @param parent parent span, if any
-    @param links
-      list of links to other spans, each with their trace state (see
-      {{:https://www.w3.org/TR/trace-context/#tracestate-header} w3.org}) *)
+  t
+
+val attrs : t -> Key_value.t list
+
+val events : t -> Event.t list
+
+val links : t -> Span_link.t list
+
+val status : t -> Span_status.t option
+
+val kind : t -> Span_kind.t option
+
+val to_span_link : t -> Span_link.t
+(** Turn the scope into a span link *)
+
+val to_span_ctx : t -> Span_ctx.t
+(** Turn the scope into a span context *)
+
+val add_event : t -> Event.t -> unit
+
+val add_event' : t -> (unit -> Event.t) -> unit
+(** Add an event to the scope. It will be aggregated into the span.
+
+    Note that this takes a function that produces an event, and will only call
+    it if there is an instrumentation backend. *)
+
+val record_exception : t -> exn -> Printexc.raw_backtrace -> unit
+
+val add_links : t -> Span_link.t list -> unit
+
+val add_links' : t -> (unit -> Span_link.t list) -> unit
+(** Add links to the scope. It will be aggregated into the span.
+
+    Note that this takes a function that produces links, and will only call it
+    if there is an instrumentation backend. *)
+
+val add_attrs : t -> (unit -> Key_value.t list) -> unit
+
+val set_status : t -> Span_status.t -> unit
+(** set the span status.
+
+    Note that this function will be called only if there is an instrumentation
+    backend. *)
+
+val set_kind : t -> Span_kind.t -> unit
+(** Set the span's kind.
+    @since 0.11 *)
diff --git a/src/core/tracer.ml b/src/core/tracer.ml
index 6045df9d..f15c6985 100644
--- a/src/core/tracer.ml
+++ b/src/core/tracer.ml
@@ -49,11 +49,11 @@ let simple_main_exporter : t =
 
     {b NOTE} be careful not to call this inside a Gc alarm, as it can cause
     deadlocks. *)
-let emit ?service_name:_ ?attrs:_ (spans : span list) : unit =
+let (emit [@deprecated "use an explicit tracer"]) =
+ fun ?service_name:_ ?attrs:_ (spans : span list) : unit ->
   match Exporter.Main_exporter.get () with
   | None -> ()
   | Some exp -> exp#send_trace spans
-[@@deprecated "use an explicit tracer"]
 
 (* TODO: remove scope, use span directly *)
 type scope = Scope.t = {
@@ -113,11 +113,11 @@ let with_' ?(tracer = simple_main_exporter) ?(force_new_trace_id = false)
             (make_status ~code:Status_code_error ~message:(Printexc.to_string e)
                ()))
     in
-    let span, _ =
+    let span =
       (* TODO: should the attrs passed to with_ go on the Span
            (in Span.create) or on the ResourceSpan (in emit)?
            (question also applies to Opentelemetry_lwt.Trace.with) *)
-      Span.create ?kind ~trace_id ?parent ~links:(Scope.links scope) ~id:span_id
+      Span.make ?kind ~trace_id ?parent ~links:(Scope.links scope) ~id:span_id
         ?trace_state ~attrs:(Scope.attrs scope) ~events:(Scope.events scope)
         ~start_time
         ~end_time:(Timestamp_ns.now_unix_ns ())
diff --git a/src/core/value.ml b/src/core/value.ml
index 97fc0503..d3d07c0e 100644
--- a/src/core/value.ml
+++ b/src/core/value.ml
@@ -17,3 +17,11 @@ let conv =
   | `Bool b -> Some (Bool_value b)
   | `Float f -> Some (Double_value f)
   | `None -> None
+
+let of_otel_opt (v : Proto.Common.any_value option) : t =
+  match v with
+  | Some (Int_value i) -> `Int (Int64.to_int i)
+  | Some (String_value s) -> `String s
+  | Some (Bool_value b) -> `Bool b
+  | Some (Double_value f) -> `Float f
+  | Some (Array_value _ | Kvlist_value _ | Bytes_value _) | None -> `None