diff --git a/lix/libstore/build/derivation-goal.cc b/lix/libstore/build/derivation-goal.cc
index 0cad92073..01972f6d9 100644
--- a/lix/libstore/build/derivation-goal.cc
+++ b/lix/libstore/build/derivation-goal.cc
@@ -1055,7 +1055,7 @@ try {
     KJ_DEFER(hook = nullptr);
     auto output = handleChildOutput();
 
-    auto buildReq = hook->rpc.buildRequest();
+    auto buildReq = hook->rpc->buildRequest();
     RPC_FILL(buildReq, setAmWilling, slotToken.valid());
     RPC_FILL(buildReq, setNeededSystem, drv->platform);
     RPC_FILL(buildReq, initDrvPath, drvPath, worker.store);
@@ -1114,8 +1114,6 @@ try {
 
     // close the rpc connection to have the hook exit
     hook->rpc = nullptr;
-    hook->client = nullptr;
-    hook->conn = nullptr;
 
     if (auto error = TRY_AWAIT(output)) {
         co_return HookResult::Accept{std::move(*error)};
diff --git a/lix/libstore/build/hook-instance.cc b/lix/libstore/build/hook-instance.cc
index 0f76d61fc..7e050d37e 100644
--- a/lix/libstore/build/hook-instance.cc
+++ b/lix/libstore/build/hook-instance.cc
@@ -7,6 +7,7 @@
 #include "lix/libutil/rpc.hh"
 #include "lix/libutil/strings.hh"
 #include "lix/libutil/types-rpc.hh" // IWYU pragma: keep
+#include <kj/memory.h>
 #include <memory>
 
 namespace nix {
@@ -76,9 +77,7 @@ try {
 
     co_return std::make_unique<HookInstance>(
         std::move(fromHook_.readSide),
-        std::move(conn),
-        std::move(client),
-        std::move(rpc),
+        kj::heap(std::move(rpc)).attach(std::move(conn), std::move(client)),
         std::move(pid)
     );
 } catch (...) {
diff --git a/lix/libstore/build/hook-instance.hh b/lix/libstore/build/hook-instance.hh
index 7d55d0a20..5bddf3ba7 100644
--- a/lix/libstore/build/hook-instance.hh
+++ b/lix/libstore/build/hook-instance.hh
@@ -19,24 +19,16 @@ struct HookInstance
      */
     AutoCloseFD fromHook;
 
-    kj::Own<kj::AsyncCapabilityStream> conn;
-    std::unique_ptr<capnp::TwoPartyClient> client;
-    rpc::build_remote::HookInstance::Client rpc;
+    kj::Own<rpc::build_remote::HookInstance::Client> rpc;
 
     std::map<ActivityId, Activity> activities;
 
     static kj::Promise<Result<std::unique_ptr<HookInstance>>> create();
 
     HookInstance(
-        AutoCloseFD fromHook,
-        kj::Own<kj::AsyncCapabilityStream> conn,
-        std::unique_ptr<capnp::TwoPartyClient> client,
-        rpc::build_remote::HookInstance::Client rpc,
-        Pid pid
+        AutoCloseFD fromHook, kj::Own<rpc::build_remote::HookInstance::Client> rpc, Pid pid
     )
         : fromHook(std::move(fromHook))
-        , conn(std::move(conn))
-        , client(std::move(client))
         , rpc(std::move(rpc))
         , pidOrStatus(std::move(pid))
     {