diff --git a/sandboxed_api/BUILD.bazel b/sandboxed_api/BUILD.bazel
index 77f1c84..302f702 100644
--- a/sandboxed_api/BUILD.bazel
+++ b/sandboxed_api/BUILD.bazel
@@ -176,12 +176,13 @@ cc_library(
         ":call",
         ":lenval_core",
         ":proto_arg_cc_proto",
+        ":var_type",
         ":vars",
-        "//sandboxed_api/sandbox2:client",
         "//sandboxed_api/sandbox2:comms",
         "//sandboxed_api/sandbox2:forkingclient",
         "//sandboxed_api/sandbox2:logsink",
         "//sandboxed_api/util:raw_logging",
+        "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/base:dynamic_annotations",
         "@com_google_absl//absl/flags:parse",
         "@com_google_absl//absl/log",
diff --git a/sandboxed_api/CMakeLists.txt b/sandboxed_api/CMakeLists.txt
index ddff045..702aa87 100644
--- a/sandboxed_api/CMakeLists.txt
+++ b/sandboxed_api/CMakeLists.txt
@@ -172,7 +172,6 @@ target_link_libraries(sapi_client
           absl::log_initialize
           absl::strings
           libffi::libffi
-          sandbox2::client
           sandbox2::comms
           sandbox2::forkingclient
           sandbox2::logsink
diff --git a/sandboxed_api/client.cc b/sandboxed_api/client.cc
index 2bae12f..7515566 100644
--- a/sandboxed_api/client.cc
+++ b/sandboxed_api/client.cc
@@ -12,18 +12,22 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include "sandboxed_api/sandbox2/client.h"
-
 #include <dlfcn.h>
 #include <sys/syscall.h>
 
+#include <algorithm>
+#include <cstdint>
+#include <cstdlib>
 #include <cstring>
 #include <iterator>
 #include <list>
+#include <type_traits>
+#include <utility>
 #include <vector>
 
 #include "google/protobuf/descriptor.h"
 #include "google/protobuf/message.h"
+#include "absl/base/attributes.h"
 #include "absl/base/dynamic_annotations.h"
 #include "absl/flags/parse.h"
 #include "absl/log/check.h"
@@ -38,6 +42,7 @@
 #include "sandboxed_api/sandbox2/forkingclient.h"
 #include "sandboxed_api/sandbox2/logsink.h"
 #include "sandboxed_api/util/raw_logging.h"
+#include "sandboxed_api/var_type.h"
 
 #include <ffi.h>
 
diff --git a/sandboxed_api/sandbox2/BUILD.bazel b/sandboxed_api/sandbox2/BUILD.bazel
index a0cd8d6..39df77f 100644
--- a/sandboxed_api/sandbox2/BUILD.bazel
+++ b/sandboxed_api/sandbox2/BUILD.bazel
@@ -576,6 +576,7 @@ cc_library(
         "//sandboxed_api/util:raw_logging",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_map",
+        "@com_google_absl//absl/status",
         "@com_google_absl//absl/strings",
     ],
 )
@@ -660,13 +661,10 @@ cc_library(
         "//sandboxed_api/util:fileops",
         "//sandboxed_api/util:raw_logging",
         "//sandboxed_api/util:status",
-        "//sandboxed_api/util:strerror",
-        "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/container:flat_hash_set",
         "@com_google_absl//absl/status",
         "@com_google_absl//absl/status:statusor",
         "@com_google_absl//absl/strings",
-        "@com_google_protobuf//:protobuf",
     ],
 )
 
@@ -819,8 +817,6 @@ cc_library(
         "//sandboxed_api/util:raw_logging",
         "//sandboxed_api/util:status",
         "//sandboxed_api/util:status_cc_proto",
-        "//sandboxed_api/util:strerror",
-        "@com_google_absl//absl/base:config",
         "@com_google_absl//absl/base:core_headers",
         "@com_google_absl//absl/base:dynamic_annotations",
         "@com_google_absl//absl/log:die_if_null",
@@ -849,9 +845,9 @@ cc_test(
         "@com_google_absl//absl/container:fixed_array",
         "@com_google_absl//absl/log",
         "@com_google_absl//absl/log:check",
+        "@com_google_absl//absl/status",
         "@com_google_absl//absl/strings",
         "@com_google_googletest//:gtest_main",
-        "@com_google_protobuf//:protobuf",
     ],
 )
 
diff --git a/sandboxed_api/sandbox2/CMakeLists.txt b/sandboxed_api/sandbox2/CMakeLists.txt
index 4649e67..8314f72 100644
--- a/sandboxed_api/sandbox2/CMakeLists.txt
+++ b/sandboxed_api/sandbox2/CMakeLists.txt
@@ -523,6 +523,7 @@ target_link_libraries(sandbox2_client
           sapi::base
           sapi::raw_logging
   PUBLIC absl::flat_hash_map
+         absl::status
          sandbox2::comms
          sandbox2::logsink
          sandbox2::network_proxy_client
@@ -612,8 +613,7 @@ target_link_libraries(sandbox2_mounts
           sapi::base
           sapi::raw_logging
           sapi::status
-  PUBLIC absl::core_headers
-         absl::status
+  PUBLIC absl::status
          absl::statusor
          absl::strings
          sandbox2::mount_tree_proto
@@ -739,7 +739,6 @@ target_link_libraries(sandbox2_comms
           absl::statusor
           absl::str_format
           absl::strings
-          sapi::strerror
           sandbox2::util
           sapi::base
           sapi::raw_logging
diff --git a/sandboxed_api/sandbox2/client.cc b/sandboxed_api/sandbox2/client.cc
index f38d187..2693697 100644
--- a/sandboxed_api/sandbox2/client.cc
+++ b/sandboxed_api/sandbox2/client.cc
@@ -25,12 +25,10 @@
 
 #include <atomic>
 #include <cinttypes>
-#include <climits>
-#include <cstddef>
 #include <cstdint>
 #include <cstdlib>
-#include <cstring>
 #include <memory>
+#include <string>
 #include <thread>  // NOLINT(build/c++11)
 #include <utility>
 
@@ -41,6 +39,7 @@
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
 #include "sandboxed_api/sandbox2/comms.h"
 #include "sandboxed_api/sandbox2/policy.h"
 #include "sandboxed_api/sandbox2/sanitizer.h"
diff --git a/sandboxed_api/sandbox2/client.h b/sandboxed_api/sandbox2/client.h
index 02484ef..241728d 100644
--- a/sandboxed_api/sandbox2/client.h
+++ b/sandboxed_api/sandbox2/client.h
@@ -21,8 +21,10 @@
 #include <cstdint>
 #include <memory>
 #include <string>
+#include <vector>
 
 #include "absl/container/flat_hash_map.h"
+#include "absl/status/status.h"
 #include "sandboxed_api/sandbox2/comms.h"
 #include "sandboxed_api/sandbox2/logsink.h"
 #include "sandboxed_api/sandbox2/network_proxy/client.h"
diff --git a/sandboxed_api/sandbox2/comms.cc b/sandboxed_api/sandbox2/comms.cc
index 0b17b7c..a200fb8 100644
--- a/sandboxed_api/sandbox2/comms.cc
+++ b/sandboxed_api/sandbox2/comms.cc
@@ -29,7 +29,6 @@
 
 #include <atomic>
 #include <cerrno>
-#include <cinttypes>
 #include <cstddef>
 #include <cstdlib>
 #include <cstring>
@@ -37,18 +36,14 @@
 #include <memory>
 
 #include "google/protobuf/message.h"
-#include "absl/base/config.h"
 #include "absl/base/dynamic_annotations.h"
-#include "absl/log/die_if_null.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
-#include "absl/strings/str_cat.h"
 #include "absl/strings/str_format.h"
 #include "absl/synchronization/mutex.h"
 #include "sandboxed_api/sandbox2/util.h"
 #include "sandboxed_api/util/raw_logging.h"
 #include "sandboxed_api/util/status.h"
-#include "sandboxed_api/util/strerror.h"
 
 namespace sandbox2 {
 
diff --git a/sandboxed_api/sandbox2/comms.h b/sandboxed_api/sandbox2/comms.h
index db44282..ac231e2 100644
--- a/sandboxed_api/sandbox2/comms.h
+++ b/sandboxed_api/sandbox2/comms.h
@@ -26,6 +26,7 @@
 #include <sys/un.h>
 #include <unistd.h>
 
+#include <cstddef>
 #include <cstdint>
 #include <limits>
 #include <memory>
@@ -33,6 +34,7 @@
 #include <utility>
 
 #include "absl/base/attributes.h"
+#include "absl/log/die_if_null.h"
 #include "absl/status/status.h"
 #include "absl/strings/string_view.h"
 #include "absl/synchronization/mutex.h"
diff --git a/sandboxed_api/sandbox2/comms_test.cc b/sandboxed_api/sandbox2/comms_test.cc
index 93d4490..3e52dbf 100644
--- a/sandboxed_api/sandbox2/comms_test.cc
+++ b/sandboxed_api/sandbox2/comms_test.cc
@@ -19,19 +19,21 @@
 #include <sys/socket.h>
 #include <sys/time.h>
 
-#include <cstdio>
+#include <cstdint>
 #include <cstring>
 #include <ctime>
-#include <sstream>
+#include <functional>
+#include <memory>
+#include <string>
 #include <thread>  // NOLINT(build/c++11)
-#include <utility>
+#include <vector>
 
-#include "google/protobuf/text_format.h"
 #include "gmock/gmock.h"
 #include "gtest/gtest.h"
 #include "absl/container/fixed_array.h"
 #include "absl/log/check.h"
 #include "absl/log/log.h"
+#include "absl/status/status.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
 #include "sandboxed_api/sandbox2/comms_test.pb.h"
diff --git a/sandboxed_api/sandbox2/mounts.cc b/sandboxed_api/sandbox2/mounts.cc
index 1ff10e8..0dddbf3 100644
--- a/sandboxed_api/sandbox2/mounts.cc
+++ b/sandboxed_api/sandbox2/mounts.cc
@@ -27,12 +27,9 @@
 #include <utility>
 #include <vector>
 
-#include "google/protobuf/util/message_differencer.h"
 #include "absl/container/flat_hash_set.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
-#include "absl/strings/ascii.h"
-#include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/str_join.h"
 #include "absl/strings/str_split.h"
@@ -45,7 +42,6 @@
 #include "sandboxed_api/util/path.h"
 #include "sandboxed_api/util/raw_logging.h"
 #include "sandboxed_api/util/status_macros.h"
-#include "sandboxed_api/util/strerror.h"
 
 namespace sandbox2 {
 namespace {
diff --git a/sandboxed_api/sandbox2/mounts.h b/sandboxed_api/sandbox2/mounts.h
index 4e7392b..dff764f 100644
--- a/sandboxed_api/sandbox2/mounts.h
+++ b/sandboxed_api/sandbox2/mounts.h
@@ -18,7 +18,6 @@
 #include <string>
 #include <vector>
 
-#include "absl/base/attributes.h"
 #include "absl/status/status.h"
 #include "absl/status/statusor.h"
 #include "absl/strings/string_view.h"