diff --git a/benchmarks/scan_benchmark.cpp b/benchmarks/scan_benchmark.cpp
index d44b31cb2..2c30861ec 100644
--- a/benchmarks/scan_benchmark.cpp
+++ b/benchmarks/scan_benchmark.cpp
@@ -26,7 +26,7 @@
 #include "support/path_pool.h"
 #include "syntax/dependency_graph.h"
 
-#include "kota/codec/json/serializer.h"
+#include "kota/codec/json/json.h"
 #include "kota/deco/deco.h"
 #include "llvm/Support/FileSystem.h"
 
diff --git a/src/compile/compilation.cpp b/src/compile/compilation.cpp
index bce235f30..ffc5bf386 100644
--- a/src/compile/compilation.cpp
+++ b/src/compile/compilation.cpp
@@ -219,9 +219,10 @@ class ProxyAction final : public clang::WrapperFrontendAction {
 
     auto CreateASTConsumer(clang::CompilerInstance& instance, llvm::StringRef file)
         -> std::unique_ptr<clang::ASTConsumer> final {
-        return std::make_unique<ProxyASTConsumer>(
-            WrapperFrontendAction::CreateASTConsumer(instance, file),
-            unit);
+        auto consumer = WrapperFrontendAction::CreateASTConsumer(instance, file);
+        if(!consumer)
+            return nullptr;
+        return std::make_unique<ProxyASTConsumer>(std::move(consumer), unit);
     }
 
     /// Make this public.
diff --git a/src/compile/compilation_unit.cpp b/src/compile/compilation_unit.cpp
index c82704f42..03d56576e 100644
--- a/src/compile/compilation_unit.cpp
+++ b/src/compile/compilation_unit.cpp
@@ -81,7 +81,8 @@ auto CompilationUnitRef::file_offset(clang::SourceLocation location) -> std::uin
 }
 
 auto CompilationUnitRef::file_path(clang::FileID fid) -> llvm::StringRef {
-    assert(fid.isValid() && "Invalid fid");
+    if(!fid.isValid())
+        return {};
     if(auto it = self->path_cache.find(fid); it != self->path_cache.end()) {
         return it->second;
     }
diff --git a/src/server/compiler.cpp b/src/server/compiler.cpp
index 349dfeb8d..0686049b4 100644
--- a/src/server/compiler.cpp
+++ b/src/server/compiler.cpp
@@ -490,6 +490,22 @@ kota::task<bool> Compiler::ensure_pch(Session& session,
     auto completion = std::make_shared<kota::event>();
     workspace.pch_cache[path_id].building = completion;
 
+    if(workspace.config.project.cache_dir.empty()) {
+        LOG_WARN("PCH build skipped: cache_dir is not configured");
+        workspace.pch_cache[path_id].building.reset();
+        completion->set();
+        co_return false;
+    }
+
+    // Ensure the PCH cache directory exists.
+    auto pch_dir = path::join(workspace.config.project.cache_dir, "cache", "pch");
+    if(auto ec = llvm::sys::fs::create_directories(pch_dir)) {
+        LOG_WARN("Cannot create PCH cache dir {}: {}", pch_dir, ec.message());
+        workspace.pch_cache[path_id].building.reset();
+        completion->set();
+        co_return false;
+    }
+
     // Build a new PCH via stateless worker.
     worker::BuildParams bp;
     bp.kind = worker::BuildKind::BuildPCH;
diff --git a/src/server/compiler.h b/src/server/compiler.h
index 2ee5bf33e..c0c7b71d5 100644
--- a/src/server/compiler.h
+++ b/src/server/compiler.h
@@ -14,7 +14,7 @@
 #include "syntax/completion.h"
 
 #include "kota/async/async.h"
-#include "kota/codec/raw_value.h"
+#include "kota/codec/json/json.h"
 #include "kota/ipc/codec/json.h"
 #include "kota/ipc/lsp/protocol.h"
 #include "kota/ipc/peer.h"
diff --git a/src/server/config.cpp b/src/server/config.cpp
index 00ee41b50..a2d8087ca 100644
--- a/src/server/config.cpp
+++ b/src/server/config.cpp
@@ -7,7 +7,7 @@
 #include "support/logging.h"
 
 #include "kota/codec/json/json.h"
-#include "kota/codec/toml.h"
+#include "kota/codec/toml/toml.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Process.h"
diff --git a/src/server/master_server.cpp b/src/server/master_server.cpp
index 790b258f0..f5a6bf853 100644
--- a/src/server/master_server.cpp
+++ b/src/server/master_server.cpp
@@ -56,9 +56,9 @@ MasterServer::MasterServer(kota::event_loop& loop,
 
 MasterServer::~MasterServer() = default;
 
-kota::task<> MasterServer::load_workspace() {
+void MasterServer::load_workspace() {
     if(workspace_root.empty())
-        co_return;
+        return;
 
     auto& cfg = workspace.config.project;
 
@@ -125,7 +125,7 @@ kota::task<> MasterServer::load_workspace() {
 
     if(cdb_path.empty()) {
         LOG_WARN("No compile_commands.json found in workspace {}", workspace_root);
-        co_return;
+        return;
     }
 
     auto count = workspace.cdb.load(cdb_path);
@@ -331,7 +331,7 @@ void MasterServer::register_handlers() {
             indexer.schedule();
         };
 
-        loop.schedule(load_workspace());
+        load_workspace();
     });
 
     peer.on_request(
diff --git a/src/server/master_server.h b/src/server/master_server.h
index 250be8d94..94106fffa 100644
--- a/src/server/master_server.h
+++ b/src/server/master_server.h
@@ -12,7 +12,7 @@
 #include "server/workspace.h"
 
 #include "kota/async/async.h"
-#include "kota/codec/raw_value.h"
+#include "kota/codec/json/json.h"
 #include "kota/ipc/peer.h"
 #include "llvm/ADT/DenseMap.h"
 
@@ -73,7 +73,7 @@ class MasterServer {
     std::string session_log_dir;
     std::string init_options_json;  ///< Raw JSON from initializationOptions, consumed once.
 
-    kota::task<> load_workspace();
+    void load_workspace();
 
     using RawResult = kota::task<kota::codec::RawValue, kota::ipc::Error>;
 };
diff --git a/src/server/protocol.h b/src/server/protocol.h
index 641c03440..1a2774c78 100644
--- a/src/server/protocol.h
+++ b/src/server/protocol.h
@@ -9,7 +9,7 @@
 
 #include "syntax/token.h"
 
-#include "kota/codec/raw_value.h"
+#include "kota/codec/json/json.h"
 #include "kota/ipc/lsp/protocol.h"
 #include "kota/ipc/protocol.h"
 
diff --git a/src/server/worker_common.h b/src/server/worker_common.h
index fb73e40df..45bfa3a46 100644
--- a/src/server/worker_common.h
+++ b/src/server/worker_common.h
@@ -8,8 +8,7 @@
 
 #include "compile/compilation.h"
 
-#include "kota/codec/json/serializer.h"
-#include "kota/codec/raw_value.h"
+#include "kota/codec/json/json.h"
 #include "kota/ipc/codec/json.h"
 
 namespace clice {
diff --git a/tests/unit/server/config_tests.cpp b/tests/unit/server/config_tests.cpp
index f29f81017..1cfb550a0 100644
--- a/tests/unit/server/config_tests.cpp
+++ b/tests/unit/server/config_tests.cpp
@@ -6,7 +6,7 @@
 #include "support/filesystem.h"
 
 #include "kota/codec/json/json.h"
-#include "kota/codec/toml.h"
+#include "kota/codec/toml/toml.h"
 
 namespace clice::testing {
 
diff --git a/tests/unit/server/stateful_worker_tests.cpp b/tests/unit/server/stateful_worker_tests.cpp
index 8ef426088..d16f6c622 100644
--- a/tests/unit/server/stateful_worker_tests.cpp
+++ b/tests/unit/server/stateful_worker_tests.cpp
@@ -5,7 +5,7 @@
 #include "server/protocol.h"
 #include "server/worker_test_helpers.h"
 
-#include "kota/codec/raw_value.h"
+#include "kota/codec/json/json.h"
 
 namespace clice::testing {
 
diff --git a/tests/unit/server/stateless_worker_tests.cpp b/tests/unit/server/stateless_worker_tests.cpp
index e79a6b795..0cc8b4848 100644
--- a/tests/unit/server/stateless_worker_tests.cpp
+++ b/tests/unit/server/stateless_worker_tests.cpp
@@ -6,7 +6,6 @@
 #include "server/worker_test_helpers.h"
 
 #include "kota/codec/bincode/bincode.h"
-#include "kota/codec/raw_value.h"
 
 namespace clice::testing {