diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index 7ba1d54a15d84362e847b22ab9c878d2d4025c1c..d3e66e9c4cc657aadb5265317e61f4022395c0d3 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -374,6 +374,8 @@ grpc_call *grpc_call_create(grpc_channel *channel, grpc_call *parent_call,
     }
     /* for now GRPC_PROPAGATE_TRACING_CONTEXT *MUST* be passed with
      * GRPC_PROPAGATE_STATS_CONTEXT */
+    /* TODO(ctiller): This should change to use the appropriate census start_op
+     * call. */
     if (propagation_mask & GRPC_PROPAGATE_CENSUS_TRACING_CONTEXT) {
       GPR_ASSERT(propagation_mask & GRPC_PROPAGATE_CENSUS_STATS_CONTEXT);
       grpc_call_context_set(call, GRPC_CONTEXT_TRACING,