diff --git a/src/core/ext/client_channel/client_channel.c b/src/core/ext/client_channel/client_channel.c
index bf64f84772c..9d92bf41c5d 100644
--- a/src/core/ext/client_channel/client_channel.c
+++ b/src/core/ext/client_channel/client_channel.c
@@ -449,7 +449,7 @@ static void on_resolver_result_changed_locked(grpc_exec_ctx *exec_ctx,
 static void start_transport_op_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                       grpc_error *error_ignored) {
   grpc_transport_op *op = arg;
-  grpc_channel_element *elem = op->transport_private.args[0];
+  grpc_channel_element *elem = op->transport_private.extra_arg;
   channel_data *chand = elem->channel_data;
 
   if (op->on_connectivity_state_change != NULL) {
diff --git a/src/core/lib/channel/compress_filter.c b/src/core/lib/channel/compress_filter.c
index 705480a0dbf..5321760e1a2 100644
--- a/src/core/lib/channel/compress_filter.c
+++ b/src/core/lib/channel/compress_filter.c
@@ -210,7 +210,8 @@ static void finish_send_message(grpc_exec_ctx *exec_ctx,
 
   grpc_slice_buffer_stream_init(&calld->replacement_stream, &calld->slices,
                                 calld->send_flags);
-  calld->send_op->send_message = &calld->replacement_stream.base;
+  calld->send_op->payload->send_message.send_message =
+      &calld->replacement_stream.base;
   calld->post_send = calld->send_op->on_complete;
   calld->send_op->on_complete = &calld->send_done;
 
diff --git a/src/core/lib/channel/message_size_filter.c b/src/core/lib/channel/message_size_filter.c
index b424c0d2acb..e99b767bef9 100644
--- a/src/core/lib/channel/message_size_filter.c
+++ b/src/core/lib/channel/message_size_filter.c
@@ -141,11 +141,13 @@ static void start_transport_stream_op(grpc_exec_ctx* exec_ctx,
                                       grpc_transport_stream_op* op) {
   call_data* calld = elem->call_data;
   // Check max send message size.
-  if (op->send_message != NULL && calld->max_send_size >= 0 &&
-      op->send_message->length > (size_t)calld->max_send_size) {
+  if (op->send_message && calld->max_send_size >= 0 &&
+      op->payload->send_message.send_message->length >
+          (size_t)calld->max_send_size) {
     char* message_string;
     gpr_asprintf(&message_string, "Sent message larger than max (%u vs. %d)",
-                 op->send_message->length, calld->max_send_size);
+                 op->payload->send_message.send_message->length,
+                 calld->max_send_size);
     grpc_transport_stream_op_finish_with_failure(
         exec_ctx, op, grpc_error_set_int(GRPC_ERROR_CREATE(message_string),
                                          GRPC_ERROR_INT_GRPC_STATUS,
@@ -154,10 +156,11 @@ static void start_transport_stream_op(grpc_exec_ctx* exec_ctx,
     return;
   }
   // Inject callback for receiving a message.
-  if (op->recv_message_ready != NULL) {
-    calld->next_recv_message_ready = op->recv_message_ready;
-    calld->recv_message = op->recv_message;
-    op->recv_message_ready = &calld->recv_message_ready;
+  if (op->payload->recv_message.recv_message_ready != NULL) {
+    calld->next_recv_message_ready =
+        op->payload->recv_message.recv_message_ready;
+    calld->recv_message = op->payload->recv_message.recv_message;
+    op->payload->recv_message.recv_message_ready = &calld->recv_message_ready;
   }
   // Chain to the next filter.
   grpc_call_next_op(exec_ctx, elem, op);
diff --git a/src/core/lib/security/transport/client_auth_filter.c b/src/core/lib/security/transport/client_auth_filter.c
index a23082a8667..98ef36518a1 100644
--- a/src/core/lib/security/transport/client_auth_filter.c
+++ b/src/core/lib/security/transport/client_auth_filter.c
@@ -120,8 +120,8 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
         GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAUTHENTICATED);
   } else {
     GPR_ASSERT(num_md <= MAX_CREDENTIALS_METADATA_COUNT);
-    GPR_ASSERT(op->send_initial_metadata != NULL);
-    mdb = op->send_initial_metadata;
+    GPR_ASSERT(op->send_initial_metadata);
+    mdb = op->payload->send_initial_metadata.send_initial_metadata;
     for (i = 0; i < num_md; i++) {
       add_error(&error,
                 grpc_metadata_batch_add_tail(
@@ -174,7 +174,9 @@ static void send_security_metadata(grpc_exec_ctx *exec_ctx,
   call_data *calld = elem->call_data;
   channel_data *chand = elem->channel_data;
   grpc_client_security_context *ctx =
-      (grpc_client_security_context *)op->context[GRPC_CONTEXT_SECURITY].value;
+      (grpc_client_security_context *)op->payload
+          ->context[GRPC_CONTEXT_SECURITY]
+          .value;
   grpc_call_credentials *channel_call_creds =
       chand->security_connector->request_metadata_creds;
   int call_creds_has_md = (ctx != NULL) && (ctx->creds != NULL);
@@ -248,23 +250,25 @@ static void auth_start_transport_op(grpc_exec_ctx *exec_ctx,
   grpc_linked_mdelem *l;
   grpc_client_security_context *sec_ctx = NULL;
 
-  if (calld->security_context_set == 0 && op->cancel_error == GRPC_ERROR_NONE) {
+  if (calld->security_context_set == 0 && !op->cancel_stream) {
     calld->security_context_set = 1;
-    GPR_ASSERT(op->context);
-    if (op->context[GRPC_CONTEXT_SECURITY].value == NULL) {
-      op->context[GRPC_CONTEXT_SECURITY].value =
+    GPR_ASSERT(op->payload->context != NULL);
+    if (op->payload->context[GRPC_CONTEXT_SECURITY].value == NULL) {
+      op->payload->context[GRPC_CONTEXT_SECURITY].value =
           grpc_client_security_context_create();
-      op->context[GRPC_CONTEXT_SECURITY].destroy =
+      op->payload->context[GRPC_CONTEXT_SECURITY].destroy =
           grpc_client_security_context_destroy;
     }
-    sec_ctx = op->context[GRPC_CONTEXT_SECURITY].value;
+    sec_ctx = op->payload->context[GRPC_CONTEXT_SECURITY].value;
     GRPC_AUTH_CONTEXT_UNREF(sec_ctx->auth_context, "client auth filter");
     sec_ctx->auth_context =
         GRPC_AUTH_CONTEXT_REF(chand->auth_context, "client_auth_filter");
   }
 
-  if (op->send_initial_metadata != NULL) {
-    for (l = op->send_initial_metadata->list.head; l != NULL; l = l->next) {
+  if (op->send_initial_metadata) {
+    for (l = op->payload->send_initial_metadata.send_initial_metadata->list
+                 .head;
+         l != NULL; l = l->next) {
       grpc_mdelem md = l->md;
       /* Pointer comparison is OK for md_elems created from the same context.
        */
diff --git a/src/core/lib/security/transport/server_auth_filter.c b/src/core/lib/security/transport/server_auth_filter.c
index 14619d97caf..afd07d69174 100644
--- a/src/core/lib/security/transport/server_auth_filter.c
+++ b/src/core/lib/security/transport/server_auth_filter.c
@@ -139,9 +139,10 @@ static void on_md_processing_done(
                         ? error_details
                         : "Authentication metadata processing failed.";
     calld->transport_op->send_initial_metadata = NULL;
-    if (calld->transport_op->send_message != NULL) {
-      grpc_byte_stream_destroy(&exec_ctx, calld->transport_op->send_message);
-      calld->transport_op->send_message = NULL;
+    if (calld->transport_op->send_message) {
+      grpc_byte_stream_destroy(
+          &exec_ctx, calld->transport_op->payload->send_message.send_message);
+      calld->transport_op->send_message = false;
     }
     calld->transport_op->send_trailing_metadata = NULL;
     grpc_closure_sched(&exec_ctx, calld->on_done_recv,
@@ -173,11 +174,14 @@ static void set_recv_ops_md_callbacks(grpc_call_element *elem,
                                       grpc_transport_stream_op *op) {
   call_data *calld = elem->call_data;
 
-  if (op->recv_initial_metadata != NULL) {
+  if (op->recv_initial_metadata) {
     /* substitute our callback for the higher callback */
-    calld->recv_initial_metadata = op->recv_initial_metadata;
-    calld->on_done_recv = op->recv_initial_metadata_ready;
-    op->recv_initial_metadata_ready = &calld->auth_on_recv;
+    calld->recv_initial_metadata =
+        op->payload->recv_initial_metadata.recv_initial_metadata;
+    calld->on_done_recv =
+        op->payload->recv_initial_metadata.recv_initial_metadata_ready;
+    op->payload->recv_initial_metadata.recv_initial_metadata_ready =
+        &calld->auth_on_recv;
     calld->transport_op = op;
   }
 }
diff --git a/src/core/lib/surface/lame_client.c b/src/core/lib/surface/lame_client.c
index 49bc4c114b3..4c2c3df14f5 100644
--- a/src/core/lib/surface/lame_client.c
+++ b/src/core/lib/surface/lame_client.c
@@ -84,10 +84,12 @@ static void lame_start_transport_stream_op(grpc_exec_ctx *exec_ctx,
                                            grpc_call_element *elem,
                                            grpc_transport_stream_op *op) {
   GRPC_CALL_LOG_OP(GPR_INFO, elem, op);
-  if (op->recv_initial_metadata != NULL) {
-    fill_metadata(exec_ctx, elem, op->recv_initial_metadata);
-  } else if (op->recv_trailing_metadata != NULL) {
-    fill_metadata(exec_ctx, elem, op->recv_trailing_metadata);
+  if (op->recv_initial_metadata) {
+    fill_metadata(exec_ctx, elem,
+                  op->payload->recv_initial_metadata.recv_initial_metadata);
+  } else if (op->recv_trailing_metadata) {
+    fill_metadata(exec_ctx, elem,
+                  op->payload->recv_trailing_metadata.recv_trailing_metadata);
   }
   grpc_transport_stream_op_finish_with_failure(
       exec_ctx, op, GRPC_ERROR_CREATE("lame client channel"));
diff --git a/src/core/lib/surface/server.c b/src/core/lib/surface/server.c
index b3605795536..17b3f8cbe50 100644
--- a/src/core/lib/surface/server.c
+++ b/src/core/lib/surface/server.c
@@ -154,8 +154,7 @@ struct call_data {
   grpc_completion_queue *cq_new;
 
   grpc_metadata_batch *recv_initial_metadata;
-  bool recv_idempotent_request;
-  bool recv_cacheable_request;
+  uint32_t recv_initial_metadata_flags;
   grpc_metadata_array initial_metadata;
 
   request_matcher *request_matcher;
@@ -498,13 +497,7 @@ static void publish_call(grpc_exec_ctx *exec_ctx, grpc_server *server,
       rc->data.batch.details->host = grpc_slice_ref_internal(calld->host);
       rc->data.batch.details->method = grpc_slice_ref_internal(calld->path);
       rc->data.batch.details->deadline = calld->deadline;
-      rc->data.batch.details->flags =
-          (calld->recv_idempotent_request
-               ? GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST
-               : 0) |
-          (calld->recv_cacheable_request
-               ? GRPC_INITIAL_METADATA_CACHEABLE_REQUEST
-               : 0);
+      rc->data.batch.details->flags = calld->recv_initial_metadata_flags;
       break;
     case REGISTERED_CALL:
       *rc->data.registered.deadline = calld->deadline;
@@ -632,7 +625,8 @@ static void start_new_rpc(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
       if (!grpc_slice_eq(rm->host, calld->host)) continue;
       if (!grpc_slice_eq(rm->method, calld->path)) continue;
       if ((rm->flags & GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) &&
-          !calld->recv_idempotent_request) {
+          0 == (calld->recv_initial_metadata_flags &
+                GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST)) {
         continue;
       }
       finish_start_new_rpc(exec_ctx, server, elem,
@@ -649,7 +643,8 @@ static void start_new_rpc(grpc_exec_ctx *exec_ctx, grpc_call_element *elem) {
       if (rm->has_host) continue;
       if (!grpc_slice_eq(rm->method, calld->path)) continue;
       if ((rm->flags & GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST) &&
-          !calld->recv_idempotent_request) {
+          0 == (calld->recv_initial_metadata_flags &
+                GRPC_INITIAL_METADATA_IDEMPOTENT_REQUEST)) {
         continue;
       }
       finish_start_new_rpc(exec_ctx, server, elem,
@@ -783,13 +778,16 @@ static void server_mutate_op(grpc_call_element *elem,
                              grpc_transport_stream_op *op) {
   call_data *calld = elem->call_data;
 
-  if (op->recv_initial_metadata != NULL) {
-    GPR_ASSERT(op->recv_idempotent_request == NULL);
-    calld->recv_initial_metadata = op->recv_initial_metadata;
-    calld->on_done_recv_initial_metadata = op->recv_initial_metadata_ready;
-    op->recv_initial_metadata_ready = &calld->server_on_recv_initial_metadata;
-    op->recv_idempotent_request = &calld->recv_idempotent_request;
-    op->recv_cacheable_request = &calld->recv_cacheable_request;
+  if (op->recv_initial_metadata) {
+    GPR_ASSERT(op->payload->recv_initial_metadata.recv_flags == NULL);
+    calld->recv_initial_metadata =
+        op->payload->recv_initial_metadata.recv_initial_metadata;
+    calld->on_done_recv_initial_metadata =
+        op->payload->recv_initial_metadata.recv_initial_metadata_ready;
+    op->payload->recv_initial_metadata.recv_initial_metadata_ready =
+        &calld->server_on_recv_initial_metadata;
+    op->payload->recv_initial_metadata.recv_flags =
+        &calld->recv_initial_metadata_flags;
   }
 }
 
diff --git a/src/core/lib/transport/transport_op_string.c b/src/core/lib/transport/transport_op_string.c
index 28360e37840..0ec6a6ea5cc 100644
--- a/src/core/lib/transport/transport_op_string.c
+++ b/src/core/lib/transport/transport_op_string.c
@@ -81,45 +81,49 @@ char *grpc_transport_stream_op_string(grpc_transport_stream_op *op) {
   gpr_strvec_add(
       &b, gpr_strdup(op->covered_by_poller ? "[COVERED]" : "[UNCOVERED]"));
 
-  if (op->send_initial_metadata != NULL) {
+  if (op->send_initial_metadata) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_strvec_add(&b, gpr_strdup("SEND_INITIAL_METADATA{"));
-    put_metadata_list(&b, *op->send_initial_metadata);
+    put_metadata_list(
+        &b, *op->payload->send_initial_metadata.send_initial_metadata);
     gpr_strvec_add(&b, gpr_strdup("}"));
   }
 
-  if (op->send_message != NULL) {
+  if (op->send_message) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_asprintf(&tmp, "SEND_MESSAGE:flags=0x%08x:len=%d",
-                 op->send_message->flags, op->send_message->length);
+                 op->payload->send_message.send_message->flags,
+                 op->payload->send_message.send_message->length);
     gpr_strvec_add(&b, tmp);
   }
 
-  if (op->send_trailing_metadata != NULL) {
+  if (op->send_trailing_metadata) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_strvec_add(&b, gpr_strdup("SEND_TRAILING_METADATA{"));
-    put_metadata_list(&b, *op->send_trailing_metadata);
+    put_metadata_list(
+        &b, *op->payload->send_trailing_metadata.send_trailing_metadata);
     gpr_strvec_add(&b, gpr_strdup("}"));
   }
 
-  if (op->recv_initial_metadata != NULL) {
+  if (op->recv_initial_metadata) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_strvec_add(&b, gpr_strdup("RECV_INITIAL_METADATA"));
   }
 
-  if (op->recv_message != NULL) {
+  if (op->recv_message) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_strvec_add(&b, gpr_strdup("RECV_MESSAGE"));
   }
 
-  if (op->recv_trailing_metadata != NULL) {
+  if (op->recv_trailing_metadata) {
     gpr_strvec_add(&b, gpr_strdup(" "));
     gpr_strvec_add(&b, gpr_strdup("RECV_TRAILING_METADATA"));
   }
 
-  if (op->cancel_error != GRPC_ERROR_NONE) {
+  if (op->cancel_stream) {
     gpr_strvec_add(&b, gpr_strdup(" "));
-    const char *msg = grpc_error_string(op->cancel_error);
+    const char *msg =
+        grpc_error_string(op->payload->cancel_stream.cancel_error);
     gpr_asprintf(&tmp, "CANCEL:%s", msg);
 
     gpr_strvec_add(&b, tmp);
diff --git a/test/core/end2end/tests/filter_causes_close.c b/test/core/end2end/tests/filter_causes_close.c
index 25e606556da..ebc6f0a52ad 100644
--- a/test/core/end2end/tests/filter_causes_close.c
+++ b/test/core/end2end/tests/filter_causes_close.c
@@ -220,9 +220,10 @@ static void start_transport_stream_op(grpc_exec_ctx *exec_ctx,
                                       grpc_call_element *elem,
                                       grpc_transport_stream_op *op) {
   call_data *calld = elem->call_data;
-  if (op->recv_initial_metadata != NULL) {
-    calld->recv_im_ready = op->recv_initial_metadata_ready;
-    op->recv_initial_metadata_ready =
+  if (op->recv_initial_metadata) {
+    calld->recv_im_ready =
+        op->payload->recv_initial_metadata.recv_initial_metadata_ready;
+    op->payload->recv_initial_metadata.recv_initial_metadata_ready =
         grpc_closure_create(recv_im_ready, elem, grpc_schedule_on_exec_ctx);
   }
   grpc_call_next_op(exec_ctx, elem, op);