diff --git a/src/trace/opentelemetry_trace.ml b/src/trace/opentelemetry_trace.ml
index f839e992..4bcbfec3 100644
--- a/src/trace/opentelemetry_trace.ml
+++ b/src/trace/opentelemetry_trace.ml
@@ -207,10 +207,10 @@ let with_ambient_span (sp : Trace.span) f =
 
 let ambient_span_provider = Ambient_span_provider_.provider
 
-let collector () : Trace.collector =
+let collector : Trace.collector =
   Trace_core.Collector.C_some ((), Collector_.callbacks)
 
-let setup () = Trace.setup_collector @@ collector ()
+let setup () = Trace.setup_collector collector
 
 let setup_with_otel_backend b : unit =
   Otel.Collector.set_backend b;
diff --git a/src/trace/opentelemetry_trace.mli b/src/trace/opentelemetry_trace.mli
index 8da7a25f..4765e213 100644
--- a/src/trace/opentelemetry_trace.mli
+++ b/src/trace/opentelemetry_trace.mli
@@ -49,11 +49,12 @@ val setup : unit -> unit
 val setup_with_otel_backend : Opentelemetry.Collector.backend -> unit
 (** Same as {!setup}, but also install the given backend as OTEL backend *)
 
-val collector : unit -> Trace_core.collector
+val collector : Trace_core.collector
 (** Make a Trace collector that uses the OTEL backend to send spans and logs *)
 
 val ambient_span_provider : Trace_core.Ambient_span_provider.t
-(** Uses {!Ambient_context} to provide contextual spans in {!Trace_core}.*)
+(** Uses {!Ambient_context} to provide contextual spans in {!Trace_core}. It is
+    automatically installed by the {!collector}. *)
 
 val link_spans : Otrace.span -> Otrace.span -> unit
 (** [link_spans sp1 sp2] modifies [sp1] by adding a span link to [sp2].