diff --git a/.github/workflows/msvc-analysis.yml b/.github/workflows/msvc-analysis.yml
index a2628f34..bd370187 100644
--- a/.github/workflows/msvc-analysis.yml
+++ b/.github/workflows/msvc-analysis.yml
@@ -25,7 +25,7 @@ env:
 jobs:
   analyze:
     name: Analyze
-    runs-on: windows-latest
+    runs-on: windows-2019
 
     steps:
       - name: Checkout repository
diff --git a/bootstrap/src/build_buildcc.cpp b/bootstrap/src/build_buildcc.cpp
index 33b1066b..70765e9d 100644
--- a/bootstrap/src/build_buildcc.cpp
+++ b/bootstrap/src/build_buildcc.cpp
@@ -62,9 +62,11 @@ void buildcc_cb(BaseTarget &target, const BaseGenerator &schema_gen,
 
   // TOOLCHAIN
   target.GlobSources("lib/toolchain/src/api");
+  target.GlobSources("lib/toolchain/src/common");
   target.AddIncludeDir("lib/toolchain/include");
   target.GlobHeaders("lib/toolchain/include/toolchain");
   target.GlobHeaders("lib/toolchain/include/toolchain/api");
+  target.GlobHeaders("lib/toolchain/include/toolchain/common");
 
   // TARGET
   target.GlobSources("lib/target/src/common");
@@ -205,33 +207,35 @@ void BuildBuildCC::Setup(const ArgToolchainState &state) {
 
   // Flatbuffers HO lib
   auto &flatbuffers_ho_lib = storage_.Add<TargetInfo>(
-      kFlatbuffersHoName,
+      kFlatbuffersHoName, toolchain_,
       TargetEnv(env_.GetTargetRootDir() / "third_party" / "flatbuffers",
                 env_.GetTargetBuildDir()));
   reg_.CallbackIf(state, flatbuffers_ho_cb, flatbuffers_ho_lib);
 
   // CLI11 HO lib
   auto &cli11_ho_lib = storage_.Add<TargetInfo>(
-      kCli11HoName, TargetEnv(env_.GetTargetRootDir() / "third_party" / "CLI11",
-                              env_.GetTargetBuildDir()));
+      kCli11HoName, toolchain_,
+      TargetEnv(env_.GetTargetRootDir() / "third_party" / "CLI11",
+                env_.GetTargetBuildDir()));
   reg_.CallbackIf(state, cli11_ho_cb, cli11_ho_lib);
 
   // fmt HO lib
   auto &fmt_ho_lib = storage_.Add<TargetInfo>(
-      kFmtHoName, TargetEnv(env_.GetTargetRootDir() / "third_party" / "fmt",
-                            env_.GetTargetBuildDir()));
+      kFmtHoName, toolchain_,
+      TargetEnv(env_.GetTargetRootDir() / "third_party" / "fmt",
+                env_.GetTargetBuildDir()));
   reg_.CallbackIf(state, fmt_ho_cb, fmt_ho_lib);
 
   // spdlog HO lib
   auto &spdlog_ho_lib = storage_.Add<TargetInfo>(
-      kSpdlogHoName,
+      kSpdlogHoName, toolchain_,
       TargetEnv(env_.GetTargetRootDir() / "third_party" / "spdlog",
                 env_.GetTargetBuildDir()));
   reg_.CallbackIf(state, spdlog_ho_cb, spdlog_ho_lib);
 
   // taskflow HO lib
   auto &taskflow_ho_lib = storage_.Add<TargetInfo>(
-      kTaskflowHoName,
+      kTaskflowHoName, toolchain_,
       TargetEnv(env_.GetTargetRootDir() / "third_party" / "taskflow",
                 env_.GetTargetBuildDir()));
   reg_.CallbackIf(state, taskflow_ho_cb, taskflow_ho_lib);
diff --git a/buildcc/lib/target/cmake/common_target_src.cmake b/buildcc/lib/target/cmake/common_target_src.cmake
index 875e5edf..6f2bb771 100644
--- a/buildcc/lib/target/cmake/common_target_src.cmake
+++ b/buildcc/lib/target/cmake/common_target_src.cmake
@@ -7,7 +7,6 @@ set(COMMON_TARGET_SRCS
     src/common/target_state.cpp
     include/target/common/target_config.h
     include/target/common/target_state.h
-    include/target/common/target_file_ext.h
     include/target/common/target_env.h
 
     src/common/util.cpp
diff --git a/buildcc/lib/target/cmake/mock_target.cmake b/buildcc/lib/target/cmake/mock_target.cmake
index da18b626..39ec8a77 100644
--- a/buildcc/lib/target/cmake/mock_target.cmake
+++ b/buildcc/lib/target/cmake/mock_target.cmake
@@ -21,7 +21,6 @@ target_link_options(mock_target PUBLIC ${TEST_LINK_FLAGS} ${BUILD_LINK_FLAGS})
 target_link_libraries(mock_target PUBLIC 
     Taskflow
 
-    mock_schema
     mock_toolchain
 
     CppUTest
diff --git a/buildcc/lib/target/cmake/target.cmake b/buildcc/lib/target/cmake/target.cmake
index fdb0cd8d..98f16479 100644
--- a/buildcc/lib/target/cmake/target.cmake
+++ b/buildcc/lib/target/cmake/target.cmake
@@ -28,7 +28,6 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
         $<INSTALL_INTERFACE:${BUILDCC_INSTALL_HEADER_PREFIX}>
     )
     target_link_libraries(target PUBLIC 
-        schema
         toolchain
         Taskflow
     )
diff --git a/buildcc/lib/target/include/target/common/target_config.h b/buildcc/lib/target/include/target/common/target_config.h
index 172c52b0..a09d2595 100644
--- a/buildcc/lib/target/include/target/common/target_config.h
+++ b/buildcc/lib/target/include/target/common/target_config.h
@@ -21,8 +21,6 @@
 #include <string>
 #include <unordered_set>
 
-#include "target/common/target_file_ext.h"
-
 namespace fs = std::filesystem;
 
 namespace buildcc {
@@ -30,77 +28,13 @@ namespace buildcc {
 struct TargetConfig {
   TargetConfig() = default;
 
-  /**
-   * @brief Get the valid file extension from a path
-   *
-   * See TargetConfig::valid_c_ext, TargetConfig::valid_cpp_ext,
-   * TargetConfig::valid_asm_ext, TargetConfig::valid_header_ext
-   *
-   * @param filepath Absolute / Relative path of the file
-   * @return TargetFileExt File path detected as per TargetConfig::valid_*
-   * variables
-   */
-  TargetFileExt GetFileExt(const fs::path &filepath) const;
-
-  /**
-   * @brief Checks for C/C++ source file validity.
-   *
-   * See TargetConfig::valid_c_ext, TargetConfig::valid_cpp_ext,
-   * TargetConfig::valid_asm_ext
-   *
-   * @param filepath Absolute / Relative path of file
-   * @return true If file extension belongs to the above valid_* list
-   * @return false If file extension does not belong to the above valid_* list
-   */
-  bool IsValidSource(const fs::path &filepath) const;
-
-  /**
-   * @brief Checks for Header file validity
-   *
-   * See TargetConfig::valid_header_ext
-   *
-   * @param filepath Absolute / Relative path of file
-   * @return true If file extension belongs to above valid_* list
-   * @return false If file extension does not belong to above valid_* list
-   */
-  bool IsValidHeader(const fs::path &filepath) const;
-
-  /**
-   * @brief Expects Source file validity
-   *
-   * env::assert_fatal if not a valid source
-   *
-   * @param filepath Absolute / Relative path of file
-   */
-  void ExpectsValidSource(const fs::path &filepath) const;
-
-  /**
-   * @brief Expects header file validity
-   *
-   * env::assert_fatal if not a valid header
-   *
-   * @param filepath Absolute / Relative path of file
-   */
-  void ExpectsValidHeader(const fs::path &filepath) const;
-
   std::string target_ext{""};
-  std::string obj_ext{".o"};
-  std::string pch_header_ext{".h"};
-  std::string pch_compile_ext{".gch"};
-
-  std::string prefix_include_dir{"-I"};
-  std::string prefix_lib_dir{"-L"};
 
   // clang-format off
   std::string pch_command{"{compiler} {preprocessor_flags} {include_dirs} {common_compile_flags} {pch_compile_flags} {compile_flags} -o {output} -c {input}"};
   std::string compile_command{"{compiler} {preprocessor_flags} {include_dirs} {common_compile_flags} {pch_object_flags} {compile_flags} -o {output} -c {input}"};
   std::string link_command{"{cpp_compiler} {link_flags} {compiled_sources} -o {output} {lib_dirs} {lib_deps}"};
   // clang-format on
-
-  std::unordered_set<std::string> valid_c_ext{".c"};
-  std::unordered_set<std::string> valid_cpp_ext{".cpp", ".cxx", ".cc"};
-  std::unordered_set<std::string> valid_asm_ext{".s", ".S", ".asm"};
-  std::unordered_set<std::string> valid_header_ext{".h", ".hpp"};
 };
 
 } // namespace buildcc
diff --git a/buildcc/lib/target/include/target/common/target_state.h b/buildcc/lib/target/include/target/common/target_state.h
index cc7e06eb..3afc766f 100644
--- a/buildcc/lib/target/include/target/common/target_state.h
+++ b/buildcc/lib/target/include/target/common/target_state.h
@@ -17,7 +17,7 @@
 #ifndef TARGET_COMMON_TARGET_STATE_H_
 #define TARGET_COMMON_TARGET_STATE_H_
 
-#include "target/common/target_file_ext.h"
+#include "toolchain/common/file_ext.h"
 
 namespace buildcc {
 
@@ -27,7 +27,7 @@ namespace buildcc {
 // TargetInfo does not have a `Build` method, it is only meant to hold
 // information
 struct TargetState {
-  void SetSourceState(TargetFileExt file_extension);
+  void SetSourceState(FileExt file_extension);
   void SetPch();
   void SetLock();
 
diff --git a/buildcc/lib/target/include/target/target.h b/buildcc/lib/target/include/target/target.h
index 4a75c230..a9540a14 100644
--- a/buildcc/lib/target/include/target/target.h
+++ b/buildcc/lib/target/include/target/target.h
@@ -70,10 +70,12 @@ class Target : public internal::BuilderInterface,
                   const Toolchain &toolchain, const TargetEnv &env,
                   const TargetConfig &config = TargetConfig())
       : TargetInfo(
+            toolchain,
             TargetEnv(env.GetTargetRootDir(),
                       env.GetTargetBuildDir() / toolchain.GetName() / name),
             config),
-        name_(name), type_(type), toolchain_(toolchain),
+        name_(name), type_(type),
+        // toolchain_(toolchain),
         // loader_(name, env_.GetTargetBuildDir()),
         serialization_(env_.GetTargetBuildDir() / fmt::format("{}.bin", name)),
         compile_pch_(*this), compile_object_(*this), link_target_(*this) {
@@ -99,8 +101,8 @@ class Target : public internal::BuilderInterface,
   void Initialize();
 
   //
-  std::optional<std::string> SelectCompileFlags(TargetFileExt ext) const;
-  std::optional<std::string> SelectCompiler(TargetFileExt ext) const;
+  std::optional<std::string> SelectCompileFlags(FileExt ext) const;
+  std::optional<std::string> SelectCompiler(FileExt ext) const;
 
   // Recompilation checks
   void RecheckPaths(const internal::path_unordered_set &previous_path,
@@ -139,7 +141,7 @@ class Target : public internal::BuilderInterface,
 private:
   std::string name_;
   TargetType type_;
-  const Toolchain &toolchain_;
+  // const Toolchain &toolchain_;
   internal::TargetSerialization serialization_;
 
   // Friend classes
diff --git a/buildcc/lib/target/include/target/target_info.h b/buildcc/lib/target/include/target/target_info.h
index aa3c22ca..fb795161 100644
--- a/buildcc/lib/target/include/target/target_info.h
+++ b/buildcc/lib/target/include/target/target_info.h
@@ -19,6 +19,8 @@
 
 #include <string>
 
+#include "toolchain/toolchain.h"
+
 #include "target/common/target_config.h"
 #include "target/common/target_env.h"
 #include "target/common/target_state.h"
@@ -60,8 +62,9 @@ class TargetInfo : public internal::SourceApi<TargetInfo>,
                    public internal::SyncApi<TargetInfo>,
                    public internal::TargetInfoGetter<TargetInfo> {
 public:
-  TargetInfo(const TargetEnv &env, const TargetConfig &config = TargetConfig())
-      : env_(env), config_(config) {}
+  TargetInfo(const BaseToolchain &toolchain, const TargetEnv &env,
+             const TargetConfig &config = TargetConfig())
+      : toolchain_(toolchain), env_(env), config_(config) {}
 
 private:
   // Inputs
@@ -79,6 +82,7 @@ class TargetInfo : public internal::SourceApi<TargetInfo>,
   friend class internal::TargetInfoGetter<TargetInfo>;
 
 protected:
+  const BaseToolchain &toolchain_;
   TargetEnv env_;
   TargetConfig config_;
 
diff --git a/buildcc/lib/target/src/api/include_api.cpp b/buildcc/lib/target/src/api/include_api.cpp
index a1716935..49ca6241 100644
--- a/buildcc/lib/target/src/api/include_api.cpp
+++ b/buildcc/lib/target/src/api/include_api.cpp
@@ -25,7 +25,7 @@ void IncludeApi<T>::AddHeaderAbsolute(const fs::path &absolute_filepath) {
   T &t = static_cast<T &>(*this);
 
   t.state_.ExpectsUnlock();
-  t.config_.ExpectsValidHeader(absolute_filepath);
+  t.toolchain_.GetConfig().ExpectsValidHeader(absolute_filepath);
   t.user_.headers.insert(absolute_filepath);
 }
 
@@ -53,7 +53,7 @@ void IncludeApi<T>::GlobHeadersAbsolute(const fs::path &absolute_path) {
   T &t = static_cast<T &>(*this);
 
   for (const auto &p : fs::directory_iterator(absolute_path)) {
-    if (t.config_.IsValidHeader(p.path())) {
+    if (t.toolchain_.GetConfig().IsValidHeader(p.path())) {
       AddHeaderAbsolute(p.path());
     }
   }
diff --git a/buildcc/lib/target/src/api/pch_api.cpp b/buildcc/lib/target/src/api/pch_api.cpp
index 60d3745e..c0695342 100644
--- a/buildcc/lib/target/src/api/pch_api.cpp
+++ b/buildcc/lib/target/src/api/pch_api.cpp
@@ -25,7 +25,7 @@ void PchApi<T>::AddPchAbsolute(const fs::path &absolute_filepath) {
   T &t = static_cast<T &>(*this);
 
   t.state_.ExpectsUnlock();
-  t.config_.ExpectsValidHeader(absolute_filepath);
+  t.toolchain_.GetConfig().ExpectsValidHeader(absolute_filepath);
 
   const fs::path absolute_pch = fs::path(absolute_filepath).make_preferred();
   t.user_.pchs.insert(absolute_pch);
diff --git a/buildcc/lib/target/src/api/source_api.cpp b/buildcc/lib/target/src/api/source_api.cpp
index 78d260a9..cc47cda3 100644
--- a/buildcc/lib/target/src/api/source_api.cpp
+++ b/buildcc/lib/target/src/api/source_api.cpp
@@ -25,7 +25,7 @@ void SourceApi<T>::AddSourceAbsolute(const fs::path &absolute_source) {
   T &t = static_cast<T &>(*this);
 
   t.state_.ExpectsUnlock();
-  t.config_.ExpectsValidSource(absolute_source);
+  t.toolchain_.GetConfig().ExpectsValidSource(absolute_source);
   t.user_.sources.emplace(fs::path(absolute_source).make_preferred());
 }
 
@@ -34,7 +34,7 @@ void SourceApi<T>::GlobSourcesAbsolute(const fs::path &absolute_source_dir) {
   T &t = static_cast<T &>(*this);
 
   for (const auto &p : fs::directory_iterator(absolute_source_dir)) {
-    if (t.config_.IsValidSource(p.path())) {
+    if (t.toolchain_.GetConfig().IsValidSource(p.path())) {
       AddSourceAbsolute(p.path());
     }
   }
@@ -59,7 +59,7 @@ void SourceApi<T>::GlobSources(const fs::path &relative_to_target_path) {
   fs::path absolute_input_path =
       t.env_.GetTargetRootDir() / relative_to_target_path;
   for (const auto &p : fs::directory_iterator(absolute_input_path)) {
-    if (t.config_.IsValidSource(p.path())) {
+    if (t.toolchain_.GetConfig().IsValidSource(p.path())) {
       AddSourceAbsolute(p.path());
     }
   }
diff --git a/buildcc/lib/target/src/common/target_config.cpp b/buildcc/lib/target/src/common/target_config.cpp
index 3f7b5135..23207ac1 100644
--- a/buildcc/lib/target/src/common/target_config.cpp
+++ b/buildcc/lib/target/src/common/target_config.cpp
@@ -22,67 +22,4 @@
 
 #include "fmt/format.h"
 
-namespace buildcc {
-
-TargetFileExt TargetConfig::GetFileExt(const fs::path &filepath) const {
-  if (!filepath.has_extension()) {
-    return TargetFileExt::Invalid;
-  }
-
-  TargetFileExt type = TargetFileExt::Invalid;
-  const std::string ext = filepath.extension().string();
-
-  if (valid_c_ext.count(ext) == 1) {
-    type = TargetFileExt::C;
-  } else if (valid_cpp_ext.count(ext) == 1) {
-    type = TargetFileExt::Cpp;
-  } else if (valid_asm_ext.count(ext) == 1) {
-    type = TargetFileExt::Asm;
-  } else if (valid_header_ext.count(ext) == 1) {
-    type = TargetFileExt::Header;
-  }
-
-  return type;
-}
-
-bool TargetConfig::IsValidSource(const fs::path &filepath) const {
-  if (!filepath.has_extension()) {
-    return false;
-  }
-
-  const std::string ext = filepath.extension().string();
-  bool valid = false;
-  if ((valid_c_ext.find(ext) != valid_c_ext.end()) ||
-      (valid_cpp_ext.find(ext) != valid_cpp_ext.end()) ||
-      (valid_asm_ext.find(ext) != valid_asm_ext.end())) {
-    valid = true;
-  }
-  return valid;
-}
-
-void TargetConfig::ExpectsValidSource(const fs::path &filepath) const {
-  env::assert_fatal(
-      IsValidSource(filepath),
-      fmt::format("{} does not have a valid source extension", filepath));
-}
-
-bool TargetConfig::IsValidHeader(const fs::path &filepath) const {
-  if (!filepath.has_extension()) {
-    return {};
-  }
-
-  const std::string ext = filepath.extension().string();
-  bool valid = false;
-  if ((valid_header_ext.find(ext) != valid_header_ext.end())) {
-    valid = true;
-  }
-  return valid;
-}
-
-void TargetConfig::ExpectsValidHeader(const fs::path &filepath) const {
-  env::assert_fatal(
-      IsValidHeader(filepath),
-      fmt::format("{} does not have a valid header extension", filepath));
-}
-
-} // namespace buildcc
+namespace buildcc {} // namespace buildcc
diff --git a/buildcc/lib/target/src/common/target_state.cpp b/buildcc/lib/target/src/common/target_state.cpp
index d2740547..95a8a022 100644
--- a/buildcc/lib/target/src/common/target_state.cpp
+++ b/buildcc/lib/target/src/common/target_state.cpp
@@ -20,19 +20,19 @@
 
 namespace buildcc {
 
-void TargetState::SetSourceState(TargetFileExt file_extension) {
+void TargetState::SetSourceState(FileExt file_extension) {
   switch (file_extension) {
-  case TargetFileExt::Asm:
+  case FileExt::Asm:
     contains_asm = true;
     break;
-  case TargetFileExt::C:
+  case FileExt::C:
     contains_c = true;
     break;
-  case TargetFileExt::Cpp:
+  case FileExt::Cpp:
     contains_cpp = true;
     break;
-  case TargetFileExt::Header:
-  case TargetFileExt::Invalid:
+  case FileExt::Header:
+  case FileExt::Invalid:
   default:
     break;
   }
diff --git a/buildcc/lib/target/src/target/build.cpp b/buildcc/lib/target/src/target/build.cpp
index 4e9de6c6..7d00cd19 100644
--- a/buildcc/lib/target/src/target/build.cpp
+++ b/buildcc/lib/target/src/target/build.cpp
@@ -66,7 +66,7 @@ void Target::Build() {
   // Source state
   for (const auto &abs_source : user_.sources) {
     // Set state
-    state_.SetSourceState(config_.GetFileExt(abs_source));
+    state_.SetSourceState(toolchain_.GetConfig().GetFileExt(abs_source));
 
     // Relate input source with output object
     compile_object_.AddObjectData(abs_source);
@@ -74,10 +74,11 @@ void Target::Build() {
 
   // Target default arguments
   command_.AddDefaultArguments({
-      {kIncludeDirs, internal::aggregate_with_prefix(config_.prefix_include_dir,
-                                                     GetIncludeDirs())},
-      {kLibDirs,
-       internal::aggregate_with_prefix(config_.prefix_lib_dir, GetLibDirs())},
+      {kIncludeDirs,
+       internal::aggregate_with_prefix(
+           toolchain_.GetConfig().prefix_include_dir, GetIncludeDirs())},
+      {kLibDirs, internal::aggregate_with_prefix(
+                     toolchain_.GetConfig().prefix_lib_dir, GetLibDirs())},
 
       {kPreprocessorFlags, internal::aggregate(GetPreprocessorFlags())},
       {kCommonCompileFlags, internal::aggregate(GetCommonCompileFlags())},
diff --git a/buildcc/lib/target/src/target/friend/compile_object.cpp b/buildcc/lib/target/src/target/friend/compile_object.cpp
index 846108df..c9b46bdf 100644
--- a/buildcc/lib/target/src/target/friend/compile_object.cpp
+++ b/buildcc/lib/target/src/target/friend/compile_object.cpp
@@ -46,7 +46,8 @@ void CompileObject::CacheCompileCommands() {
         fmt::format("{}", GetObjectData(absolute_current_source).output);
     const std::string input = fmt::format("{}", absolute_current_source);
 
-    const auto type = target_.config_.GetFileExt(absolute_current_source);
+    const auto type =
+        target_.toolchain_.GetConfig().GetFileExt(absolute_current_source);
     const std::string selected_aggregated_compile_flags =
         target_.SelectCompileFlags(type).value_or("");
     const std::string selected_compiler =
@@ -156,7 +157,7 @@ CompileObject::ConstructObjectPath(const fs::path &absolute_source_file) const {
   fs::path absolute_compiled_source = target_.GetTargetBuildDir() / relative;
   absolute_compiled_source.replace_filename(
       fmt::format("{}{}", absolute_source_file.filename().string(),
-                  target_.GetConfig().obj_ext));
+                  target_.toolchain_.GetConfig().obj_ext));
   return absolute_compiled_source;
 }
 
diff --git a/buildcc/lib/target/src/target/friend/compile_pch.cpp b/buildcc/lib/target/src/target/friend/compile_pch.cpp
index 971f36f1..312b8b7c 100644
--- a/buildcc/lib/target/src/target/friend/compile_pch.cpp
+++ b/buildcc/lib/target/src/target/friend/compile_pch.cpp
@@ -117,13 +117,14 @@ void CompilePch::BuildCompile() {
 
 fs::path CompilePch::ConstructHeaderPath() const {
   return target_.GetTargetBuildDir() /
-         fmt::format("buildcc_pch{}", target_.GetConfig().pch_header_ext);
+         fmt::format("buildcc_pch{}",
+                     target_.toolchain_.GetConfig().pch_header_ext);
 }
 
 fs::path CompilePch::ConstructCompilePath() const {
   return ConstructHeaderPath().replace_extension(
-      fmt::format("{}{}", target_.GetConfig().pch_header_ext,
-                  target_.GetConfig().pch_compile_ext));
+      fmt::format("{}{}", target_.toolchain_.GetConfig().pch_header_ext,
+                  target_.toolchain_.GetConfig().pch_compile_ext));
 }
 
 fs::path CompilePch::ConstructSourcePath(bool has_cpp) const {
@@ -133,7 +134,7 @@ fs::path CompilePch::ConstructSourcePath(bool has_cpp) const {
 
 fs::path CompilePch::ConstructObjectPath() const {
   return ConstructHeaderPath().replace_extension(
-      fmt::format("{}", target_.GetConfig().obj_ext));
+      fmt::format("{}", target_.toolchain_.GetConfig().obj_ext));
 }
 
 std::string CompilePch::ConstructCompileCommand() const {
@@ -141,14 +142,14 @@ std::string CompilePch::ConstructCompileCommand() const {
                              ? target_.GetToolchain().GetCppCompiler()
                              : target_.GetToolchain().GetCCompiler();
   compiler = fmt::format("{}", fs::path(compiler));
-  const TargetFileExt file_ext_type =
-      target_.GetState().contains_cpp ? TargetFileExt::Cpp : TargetFileExt::C;
+  const FileExt file_ext_type =
+      target_.GetState().contains_cpp ? FileExt::Cpp : FileExt::C;
   const std::string compile_flags =
       target_.SelectCompileFlags(file_ext_type).value_or("");
   const std::string pch_compile_path = fmt::format("{}", compile_path_);
   const std::string pch_header_path = fmt::format("{}", header_path_);
   const std::string pch_source_path = fmt::format("{}", source_path_);
-  return target_.command_.Construct(target_.config_.pch_command,
+  return target_.command_.Construct(target_.GetConfig().pch_command,
                                     {
                                         {kCompiler, compiler},
                                         {kCompileFlags, compile_flags},
diff --git a/buildcc/lib/target/src/target/friend/link_target.cpp b/buildcc/lib/target/src/target/friend/link_target.cpp
index 2c6fd30e..49bc52b7 100644
--- a/buildcc/lib/target/src/target/friend/link_target.cpp
+++ b/buildcc/lib/target/src/target/friend/link_target.cpp
@@ -36,7 +36,7 @@ void LinkTarget::CacheLinkCommand() {
   const std::string output_target = fmt::format("{}", output_);
   const auto &target_user_schema = target_.user_;
   command_ = target_.command_.Construct(
-      target_.config_.link_command,
+      target_.GetConfig().link_command,
       {
           {kOutput, output_target},
           {kCompiledSources, aggregated_compiled_sources},
diff --git a/buildcc/lib/target/src/target/target.cpp b/buildcc/lib/target/src/target/target.cpp
index 571cd9a4..dd4aedbe 100644
--- a/buildcc/lib/target/src/target/target.cpp
+++ b/buildcc/lib/target/src/target/target.cpp
@@ -89,15 +89,15 @@ void Target::RecheckExternalLib(
                  std::bind(&Target::ExternalLibChanged, this));
 }
 
-std::optional<std::string> Target::SelectCompileFlags(TargetFileExt ext) const {
+std::optional<std::string> Target::SelectCompileFlags(FileExt ext) const {
   switch (ext) {
-  case TargetFileExt::Asm:
+  case FileExt::Asm:
     return internal::aggregate(GetAsmCompileFlags());
     break;
-  case TargetFileExt::C:
+  case FileExt::C:
     return internal::aggregate(GetCCompileFlags());
     break;
-  case TargetFileExt::Cpp:
+  case FileExt::Cpp:
     return internal::aggregate(GetCppCompileFlags());
     break;
   default:
@@ -106,15 +106,15 @@ std::optional<std::string> Target::SelectCompileFlags(TargetFileExt ext) const {
   return {};
 }
 
-std::optional<std::string> Target::SelectCompiler(TargetFileExt ext) const {
+std::optional<std::string> Target::SelectCompiler(FileExt ext) const {
   switch (ext) {
-  case TargetFileExt::Asm:
+  case FileExt::Asm:
     return GetToolchain().GetAsmCompiler();
     break;
-  case TargetFileExt::C:
+  case FileExt::C:
     return GetToolchain().GetCCompiler();
     break;
-  case TargetFileExt::Cpp:
+  case FileExt::Cpp:
     return GetToolchain().GetCppCompiler();
     break;
   default:
diff --git a/buildcc/lib/target/test/target/CMakeLists.txt b/buildcc/lib/target/test/target/CMakeLists.txt
index 9b914b55..83d29bbe 100644
--- a/buildcc/lib/target/test/target/CMakeLists.txt
+++ b/buildcc/lib/target/test/target/CMakeLists.txt
@@ -25,17 +25,11 @@ add_test(NAME test_serialization_interface COMMAND test_serialization_interface
 )
 
 # Common
-add_executable(test_target_config
-    test_target_config.cpp
-)
-target_link_libraries(test_target_config PRIVATE target_interface)
-
 add_executable(test_target_state
     test_target_state.cpp
 )
 target_link_libraries(test_target_state PRIVATE target_interface)
 
-add_test(NAME test_target_config COMMAND test_target_config)
 add_test(NAME test_target_state COMMAND test_target_state)
 
 # Generator
diff --git a/buildcc/lib/target/test/target/test_target_config.cpp b/buildcc/lib/target/test/target/test_target_config.cpp
deleted file mode 100644
index e0fcfcf0..00000000
--- a/buildcc/lib/target/test/target/test_target_config.cpp
+++ /dev/null
@@ -1,41 +0,0 @@
-#include "target/common/target_config.h"
-
-// NOTE, Make sure all these includes are AFTER the system and header includes
-#include "CppUTest/CommandLineTestRunner.h"
-#include "CppUTest/MemoryLeakDetectorNewMacros.h"
-#include "CppUTest/TestHarness.h"
-#include "CppUTest/Utest.h"
-
-// clang-format off
-TEST_GROUP(TargetConfigTestGroup)
-{
-};
-// clang-format on
-
-TEST(TargetConfigTestGroup, GetFileExt) {
-  buildcc::TargetConfig target_config;
-
-  buildcc::TargetFileExt ext;
-
-  ext = target_config.GetFileExt("file.asm");
-  CHECK(ext == buildcc::TargetFileExt::Asm);
-
-  ext = target_config.GetFileExt("file.c");
-  CHECK(ext == buildcc::TargetFileExt::C);
-
-  ext = target_config.GetFileExt("file.cpp");
-  CHECK(ext == buildcc::TargetFileExt::Cpp);
-
-  ext = target_config.GetFileExt("file.h");
-  CHECK(ext == buildcc::TargetFileExt::Header);
-
-  ext = target_config.GetFileExt("file.invalid");
-  CHECK(ext == buildcc::TargetFileExt::Invalid);
-
-  ext = target_config.GetFileExt("random/directory");
-  CHECK(ext == buildcc::TargetFileExt::Invalid);
-}
-
-int main(int ac, char **av) {
-  return CommandLineTestRunner::RunAllTests(ac, av);
-}
diff --git a/buildcc/lib/target/test/target/test_target_state.cpp b/buildcc/lib/target/test/target/test_target_state.cpp
index 33900732..f3af3363 100644
--- a/buildcc/lib/target/test/target/test_target_state.cpp
+++ b/buildcc/lib/target/test/target/test_target_state.cpp
@@ -1,5 +1,5 @@
-#include "target/common/target_file_ext.h"
 #include "target/common/target_state.h"
+#include "toolchain/common/file_ext.h"
 
 // NOTE, Make sure all these includes are AFTER the system and header includes
 #include "CppUTest/CommandLineTestRunner.h"
@@ -17,20 +17,20 @@ TEST(TargetStateTestGroup, SetSourceState) {
   buildcc::TargetState target_state;
 
   CHECK_FALSE(target_state.contains_c);
-  target_state.SetSourceState(buildcc::TargetFileExt::C);
+  target_state.SetSourceState(buildcc::FileExt::C);
   CHECK_TRUE(target_state.contains_c);
 
   CHECK_FALSE(target_state.contains_cpp);
-  target_state.SetSourceState(buildcc::TargetFileExt::Cpp);
+  target_state.SetSourceState(buildcc::FileExt::Cpp);
   CHECK_TRUE(target_state.contains_cpp);
 
   CHECK_FALSE(target_state.contains_asm);
-  target_state.SetSourceState(buildcc::TargetFileExt::Asm);
+  target_state.SetSourceState(buildcc::FileExt::Asm);
   CHECK_TRUE(target_state.contains_asm);
 
   // Ignored
-  target_state.SetSourceState(buildcc::TargetFileExt::Header);
-  target_state.SetSourceState(buildcc::TargetFileExt::Invalid);
+  target_state.SetSourceState(buildcc::FileExt::Header);
+  target_state.SetSourceState(buildcc::FileExt::Invalid);
 }
 
 int main(int ac, char **av) {
diff --git a/buildcc/lib/toolchain/CMakeLists.txt b/buildcc/lib/toolchain/CMakeLists.txt
index edb0cc09..712131ff 100644
--- a/buildcc/lib/toolchain/CMakeLists.txt
+++ b/buildcc/lib/toolchain/CMakeLists.txt
@@ -1,6 +1,12 @@
 set(TOOLCHAIN_SRCS
     include/toolchain/toolchain.h
 
+    include/toolchain/common/file_ext.h
+
+    src/common/toolchain_config.cpp
+    include/toolchain/common/toolchain_config.h
+
+    # Features
     src/api/toolchain_verify.cpp
     include/toolchain/api/toolchain_verify.h
 )
@@ -14,7 +20,7 @@ if (${TESTING})
     target_compile_options(mock_toolchain PUBLIC ${TEST_COMPILE_FLAGS} ${BUILD_COMPILE_FLAGS})
     target_link_options(mock_toolchain PUBLIC ${TEST_LINK_FLAGS} ${BUILD_LINK_FLAGS})
     target_link_libraries(mock_toolchain PUBLIC
-        mock_env
+        mock_schema
 
         CppUTest
         CppUTestExt
@@ -28,9 +34,17 @@ if (${TESTING})
         mock_toolchain
     )
 
+    add_executable(test_toolchain_config
+        test/test_toolchain_config.cpp
+    )
+    target_link_libraries(test_toolchain_config PRIVATE
+        mock_toolchain
+    )
+
     add_test(NAME test_toolchain_verify COMMAND test_toolchain_verify
         WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}/test
     )
+    add_test(NAME test_toolchain_config COMMAND test_toolchain_config)
 endif()
 
 if(${BUILDCC_BUILD_AS_SINGLE_LIB})
@@ -53,7 +67,7 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
         $<INSTALL_INTERFACE:${BUILDCC_INSTALL_HEADER_PREFIX}>
     )
     target_link_libraries(toolchain PUBLIC 
-        env
+        schema
     )
 endif()
 
diff --git a/buildcc/lib/target/include/target/common/target_file_ext.h b/buildcc/lib/toolchain/include/toolchain/common/file_ext.h
similarity index 88%
rename from buildcc/lib/target/include/target/common/target_file_ext.h
rename to buildcc/lib/toolchain/include/toolchain/common/file_ext.h
index bab96289..64a35660 100644
--- a/buildcc/lib/target/include/target/common/target_file_ext.h
+++ b/buildcc/lib/toolchain/include/toolchain/common/file_ext.h
@@ -14,12 +14,12 @@
  * limitations under the License.
  */
 
-#ifndef TARGET_COMMON_TARGET_FILE_EXT_H_
-#define TARGET_COMMON_TARGET_FILE_EXT_H_
+#ifndef TOOLCHAIN_COMMON_FILE_EXT_H_
+#define TOOLCHAIN_COMMON_FILE_EXT_H_
 
 namespace buildcc {
 
-enum class TargetFileExt {
+enum class FileExt {
   Asm,     ///< Valid Assembly source extension
   C,       ///< Valid C source extension
   Cpp,     ///< Valid Cpp source extension
diff --git a/buildcc/lib/toolchain/include/toolchain/common/toolchain_config.h b/buildcc/lib/toolchain/include/toolchain/common/toolchain_config.h
new file mode 100644
index 00000000..8cdcce3b
--- /dev/null
+++ b/buildcc/lib/toolchain/include/toolchain/common/toolchain_config.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright 2021-2022 Niket Naidu. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef TOOLCHAIN_COMMON_TOOLCHAIN_CONFIG_H_
+#define TOOLCHAIN_COMMON_TOOLCHAIN_CONFIG_H_
+
+#include <filesystem>
+#include <string>
+#include <unordered_set>
+
+#include "toolchain/common/file_ext.h"
+
+namespace fs = std::filesystem;
+
+namespace buildcc {
+
+struct ToolchainConfig {
+  ToolchainConfig() = default;
+
+  /**
+   * @brief Get the valid file extension from a path
+   *
+   * See ToolchainConfig::valid_c_ext, ToolchainConfig::valid_cpp_ext,
+   * ToolchainConfig::valid_asm_ext, ToolchainConfig::valid_header_ext
+   *
+   * @param filepath Absolute / Relative path of the file
+   * @return FileExt File path detected as per Toolchain::valid_*
+   * variables
+   */
+  FileExt GetFileExt(const fs::path &filepath) const;
+
+  /**
+   * @brief Checks for C/C++ source file validity.
+   *
+   * See ToolchainConfig::valid_c_ext, ToolchainConfig::valid_cpp_ext,
+   * ToolchainConfig::valid_asm_ext
+   *
+   * @param filepath Absolute / Relative path of file
+   * @return true If file extension belongs to the above valid_* list
+   * @return false If file extension does not belong to the above valid_* list
+   */
+  bool IsValidSource(const fs::path &filepath) const;
+
+  /**
+   * @brief Checks for Header file validity
+   *
+   * See ToolchainConfig::valid_header_ext
+   *
+   * @param filepath Absolute / Relative path of file
+   * @return true If file extension belongs to above valid_* list
+   * @return false If file extension does not belong to above valid_* list
+   */
+  bool IsValidHeader(const fs::path &filepath) const;
+
+  /**
+   * @brief Expects Source file validity
+   *
+   * env::assert_fatal if not a valid source
+   *
+   * @param filepath Absolute / Relative path of file
+   */
+  void ExpectsValidSource(const fs::path &filepath) const;
+
+  /**
+   * @brief Expects header file validity
+   *
+   * env::assert_fatal if not a valid header
+   *
+   * @param filepath Absolute / Relative path of file
+   */
+  void ExpectsValidHeader(const fs::path &filepath) const;
+
+  std::string obj_ext{".o"};
+  std::string pch_header_ext{".h"};
+  std::string pch_compile_ext{".gch"};
+
+  std::string prefix_include_dir{"-I"};
+  std::string prefix_lib_dir{"-L"};
+
+  std::unordered_set<std::string> valid_c_ext{".c"};
+  std::unordered_set<std::string> valid_cpp_ext{".cpp", ".cxx", ".cc"};
+  std::unordered_set<std::string> valid_asm_ext{".s", ".S", ".asm"};
+  std::unordered_set<std::string> valid_header_ext{".h", ".hpp"};
+};
+
+} // namespace buildcc
+
+#endif
diff --git a/buildcc/lib/toolchain/include/toolchain/toolchain.h b/buildcc/lib/toolchain/include/toolchain/toolchain.h
index f46c3d41..dec04968 100644
--- a/buildcc/lib/toolchain/include/toolchain/toolchain.h
+++ b/buildcc/lib/toolchain/include/toolchain/toolchain.h
@@ -21,7 +21,9 @@
 #include <unordered_map>
 #include <vector>
 
-#include "api/toolchain_verify.h"
+#include "toolchain/common/toolchain_config.h"
+
+#include "toolchain/api/toolchain_verify.h"
 
 namespace buildcc {
 
@@ -41,10 +43,13 @@ class Toolchain : public ToolchainVerify<Toolchain> {
   explicit Toolchain(Id id, std::string_view name,
                      std::string_view asm_compiler, std::string_view c_compiler,
                      std::string_view cpp_compiler, std::string_view archiver,
-                     std::string_view linker)
+                     std::string_view linker,
+                     const ToolchainConfig &config = ToolchainConfig())
       : id_(id), name_(name), asm_compiler_(asm_compiler),
         c_compiler_(c_compiler), cpp_compiler_(cpp_compiler),
-        archiver_(archiver), linker_(linker) {}
+        archiver_(archiver), linker_(linker), config_(config) {
+    UpdateConfig(config_);
+  }
 
   Toolchain(Toolchain &&toolchain) = default;
   Toolchain(const Toolchain &toolchain) = delete;
@@ -58,6 +63,11 @@ class Toolchain : public ToolchainVerify<Toolchain> {
   const std::string &GetArchiver() const { return archiver_; }
   const std::string &GetLinker() const { return linker_; }
 
+  const ToolchainConfig &GetConfig() const { return config_; }
+
+private:
+  virtual void UpdateConfig(ToolchainConfig &config) { (void)config; }
+
 private:
   friend class ToolchainVerify<Toolchain>;
 
@@ -69,6 +79,8 @@ class Toolchain : public ToolchainVerify<Toolchain> {
   std::string cpp_compiler_;
   std::string archiver_;
   std::string linker_;
+
+  ToolchainConfig config_;
 };
 
 typedef Toolchain::Id ToolchainId;
diff --git a/buildcc/lib/toolchain/src/common/toolchain_config.cpp b/buildcc/lib/toolchain/src/common/toolchain_config.cpp
new file mode 100644
index 00000000..55125dd4
--- /dev/null
+++ b/buildcc/lib/toolchain/src/common/toolchain_config.cpp
@@ -0,0 +1,88 @@
+/*
+ * Copyright 2021-2022 Niket Naidu. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "toolchain/common/toolchain_config.h"
+
+#include "env/assert_fatal.h"
+
+#include "schema/path.h"
+
+#include "fmt/format.h"
+
+namespace buildcc {
+
+FileExt ToolchainConfig::GetFileExt(const fs::path &filepath) const {
+  if (!filepath.has_extension()) {
+    return FileExt::Invalid;
+  }
+
+  FileExt type = FileExt::Invalid;
+  const std::string ext = filepath.extension().string();
+
+  if (valid_c_ext.count(ext) == 1) {
+    type = FileExt::C;
+  } else if (valid_cpp_ext.count(ext) == 1) {
+    type = FileExt::Cpp;
+  } else if (valid_asm_ext.count(ext) == 1) {
+    type = FileExt::Asm;
+  } else if (valid_header_ext.count(ext) == 1) {
+    type = FileExt::Header;
+  }
+
+  return type;
+}
+
+bool ToolchainConfig::IsValidSource(const fs::path &filepath) const {
+  if (!filepath.has_extension()) {
+    return false;
+  }
+
+  const std::string ext = filepath.extension().string();
+  bool valid = false;
+  if ((valid_c_ext.find(ext) != valid_c_ext.end()) ||
+      (valid_cpp_ext.find(ext) != valid_cpp_ext.end()) ||
+      (valid_asm_ext.find(ext) != valid_asm_ext.end())) {
+    valid = true;
+  }
+  return valid;
+}
+
+void ToolchainConfig::ExpectsValidSource(const fs::path &filepath) const {
+  env::assert_fatal(
+      IsValidSource(filepath),
+      fmt::format("{} does not have a valid source extension", filepath));
+}
+
+bool ToolchainConfig::IsValidHeader(const fs::path &filepath) const {
+  if (!filepath.has_extension()) {
+    return {};
+  }
+
+  const std::string ext = filepath.extension().string();
+  bool valid = false;
+  if ((valid_header_ext.find(ext) != valid_header_ext.end())) {
+    valid = true;
+  }
+  return valid;
+}
+
+void ToolchainConfig::ExpectsValidHeader(const fs::path &filepath) const {
+  env::assert_fatal(
+      IsValidHeader(filepath),
+      fmt::format("{} does not have a valid header extension", filepath));
+}
+
+} // namespace buildcc
diff --git a/buildcc/lib/toolchain/test/test_toolchain_config.cpp b/buildcc/lib/toolchain/test/test_toolchain_config.cpp
new file mode 100644
index 00000000..a0cfce24
--- /dev/null
+++ b/buildcc/lib/toolchain/test/test_toolchain_config.cpp
@@ -0,0 +1,41 @@
+#include "toolchain/common/toolchain_config.h"
+
+// NOTE, Make sure all these includes are AFTER the system and header includes
+#include "CppUTest/CommandLineTestRunner.h"
+#include "CppUTest/MemoryLeakDetectorNewMacros.h"
+#include "CppUTest/TestHarness.h"
+#include "CppUTest/Utest.h"
+
+// clang-format off
+TEST_GROUP(ToolchainConfigTestGroup)
+{
+};
+// clang-format on
+
+TEST(ToolchainConfigTestGroup, GetFileExt) {
+  buildcc::ToolchainConfig toolchain_config;
+
+  buildcc::FileExt ext;
+
+  ext = toolchain_config.GetFileExt("file.asm");
+  CHECK(ext == buildcc::FileExt::Asm);
+
+  ext = toolchain_config.GetFileExt("file.c");
+  CHECK(ext == buildcc::FileExt::C);
+
+  ext = toolchain_config.GetFileExt("file.cpp");
+  CHECK(ext == buildcc::FileExt::Cpp);
+
+  ext = toolchain_config.GetFileExt("file.h");
+  CHECK(ext == buildcc::FileExt::Header);
+
+  ext = toolchain_config.GetFileExt("file.invalid");
+  CHECK(ext == buildcc::FileExt::Invalid);
+
+  ext = toolchain_config.GetFileExt("random/directory");
+  CHECK(ext == buildcc::FileExt::Invalid);
+}
+
+int main(int ac, char **av) {
+  return CommandLineTestRunner::RunAllTests(ac, av);
+}
diff --git a/buildcc/schema/cmake/schema.cmake b/buildcc/schema/cmake/schema.cmake
index 99d9949c..a3d21867 100644
--- a/buildcc/schema/cmake/schema.cmake
+++ b/buildcc/schema/cmake/schema.cmake
@@ -68,6 +68,9 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
         $<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>
         $<INSTALL_INTERFACE:${BUILDCC_INSTALL_HEADER_PREFIX}>
     )
+    target_link_libraries(schema PUBLIC
+        env
+    )
     target_include_directories(schema PRIVATE
         ${SCHEMA_BUILD_DIR}
     )
@@ -75,7 +78,6 @@ if(${BUILDCC_BUILD_AS_INTERFACE})
     target_link_options(schema PRIVATE ${BUILD_LINK_FLAGS})
     target_link_libraries(schema PRIVATE
         flatbuffers_header_only
-        env
     )
     add_dependencies(schema fbs_to_header)
 endif()
diff --git a/buildcc/targets/include/targets/target_gcc.h b/buildcc/targets/include/targets/target_gcc.h
index 60df007f..2e2dfb32 100644
--- a/buildcc/targets/include/targets/target_gcc.h
+++ b/buildcc/targets/include/targets/target_gcc.h
@@ -29,14 +29,6 @@ constexpr const char *const kGccExecutableExt = "";
 constexpr const char *const kGccStaticLibExt = ".a";
 constexpr const char *const kGccDynamicLibExt = ".so";
 
-constexpr const char *const kGccObjExt = ".o";
-constexpr const char *const kGccPchHeaderExt = ".h";
-constexpr const char *const kGccPchCompileExt = ".gch";
-
-// GCC
-constexpr const char *const kGccPrefixIncludeDir = "-I";
-constexpr const char *const kGccPrefixLibDir = "-L";
-
 constexpr const char *const kGccGenericPchCompileCommand =
     "{compiler} {preprocessor_flags} {include_dirs} {common_compile_flags} "
     "{pch_compile_flags} {compile_flags} -o {output} -c {input}";
@@ -72,11 +64,6 @@ class GccConfig : ConfigInterface<GccConfig> {
                                        const std::string &link_command) {
     TargetConfig config;
     config.target_ext = target_ext;
-    config.obj_ext = kGccObjExt;
-    config.pch_header_ext = kGccPchHeaderExt;
-    config.pch_compile_ext = kGccPchCompileExt;
-    std::string prefix_include_dir = kGccPrefixIncludeDir;
-    std::string prefix_lib_dir = kGccPrefixLibDir;
     config.pch_command = kGccGenericPchCompileCommand;
     config.compile_command = compile_command;
     config.link_command = link_command;
diff --git a/buildcc/targets/include/targets/target_mingw.h b/buildcc/targets/include/targets/target_mingw.h
index 44f93720..abaeeb38 100644
--- a/buildcc/targets/include/targets/target_mingw.h
+++ b/buildcc/targets/include/targets/target_mingw.h
@@ -54,11 +54,6 @@ class MingwConfig : ConfigInterface<MingwConfig> {
                                          const std::string &link_command) {
     TargetConfig config;
     config.target_ext = target_ext;
-    config.obj_ext = kGccObjExt;
-    config.pch_header_ext = kGccPchHeaderExt;
-    config.pch_compile_ext = kGccPchCompileExt;
-    std::string prefix_include_dir = kGccPrefixIncludeDir;
-    std::string prefix_lib_dir = kGccPrefixLibDir;
     config.pch_command = kGccGenericPchCompileCommand;
     config.compile_command = compile_command;
     config.link_command = link_command;
diff --git a/buildcc/targets/include/targets/target_msvc.h b/buildcc/targets/include/targets/target_msvc.h
index 0d8e91ae..7baaae88 100644
--- a/buildcc/targets/include/targets/target_msvc.h
+++ b/buildcc/targets/include/targets/target_msvc.h
@@ -33,13 +33,6 @@ constexpr const char *const kMsvcStaticLibExt = ".lib";
 // OUT .dll needs to be present in the executable folder during runtime
 constexpr const char *const kMsvcDynamicLibExt = ".lib";
 
-constexpr const char *const kMsvcObjExt = ".obj";
-constexpr const char *const kMsvcPchHeaderExt = ".h";
-constexpr const char *const kMsvcPchCompileExt = ".pch";
-
-constexpr const char *const kMsvcPrefixIncludeDir = "/I";
-constexpr const char *const kMsvcPrefixLibDir = "/LIBPATH:";
-
 constexpr const char *const kMsvcPchCompileCommand =
     "{compiler} {preprocessor_flags} {include_dirs} {common_compile_flags} "
     "/Yc{input} /FI{input} /Fp{output} {pch_compile_flags} {compile_flags} "
@@ -79,11 +72,6 @@ class MsvcConfig : ConfigInterface<MsvcConfig> {
                                         const std::string &link_command) {
     TargetConfig config;
     config.target_ext = target_ext;
-    config.obj_ext = kMsvcObjExt;
-    config.pch_header_ext = kMsvcPchHeaderExt;
-    config.pch_compile_ext = kMsvcPchCompileExt;
-    config.prefix_include_dir = kMsvcPrefixIncludeDir;
-    config.prefix_lib_dir = kMsvcPrefixLibDir;
     config.pch_command = kMsvcPchCompileCommand;
     config.compile_command = compile_command;
     config.link_command = link_command;
diff --git a/buildcc/toolchains/include/toolchains/toolchain_gcc.h b/buildcc/toolchains/include/toolchains/toolchain_gcc.h
index b7c490fb..ebf4be40 100644
--- a/buildcc/toolchains/include/toolchains/toolchain_gcc.h
+++ b/buildcc/toolchains/include/toolchains/toolchain_gcc.h
@@ -21,6 +21,12 @@
 
 namespace buildcc {
 
+constexpr const char *const kGccObjExt = ".o";
+constexpr const char *const kGccPchHeaderExt = ".h";
+constexpr const char *const kGccPchCompileExt = ".gch";
+constexpr const char *const kGccPrefixIncludeDir = "-I";
+constexpr const char *const kGccPrefixLibDir = "-L";
+
 /**
  * @brief Generic GCC Toolchain <br>
  * id = ToolchainId::Gcc <br>
@@ -36,6 +42,15 @@ class Toolchain_gcc : public Toolchain {
   Toolchain_gcc()
       : Toolchain(Toolchain::Id::Gcc, "gcc", "as", "gcc", "g++", "ar", "ld") {}
   Toolchain_gcc(const Toolchain_gcc &gcc) = delete;
+
+private:
+  void UpdateConfig(ToolchainConfig &config) override {
+    config.obj_ext = kGccObjExt;
+    config.pch_header_ext = kGccPchHeaderExt;
+    config.pch_compile_ext = kGccPchCompileExt;
+    config.prefix_include_dir = kGccPrefixIncludeDir;
+    config.prefix_lib_dir = kGccPrefixLibDir;
+  }
 };
 
 } // namespace buildcc
diff --git a/buildcc/toolchains/include/toolchains/toolchain_mingw.h b/buildcc/toolchains/include/toolchains/toolchain_mingw.h
index 44d4b09b..05bef7ca 100644
--- a/buildcc/toolchains/include/toolchains/toolchain_mingw.h
+++ b/buildcc/toolchains/include/toolchains/toolchain_mingw.h
@@ -21,6 +21,12 @@
 
 namespace buildcc {
 
+constexpr const char *const kMingwObjExt = ".o";
+constexpr const char *const kMingwPchHeaderExt = ".h";
+constexpr const char *const kMingwPchCompileExt = ".gch";
+constexpr const char *const kMingwPrefixIncludeDir = "-I";
+constexpr const char *const kMingwPrefixLibDir = "-L";
+
 /**
  * @brief Generic MinGW Toolchain <br>
  * id = ToolchainId::MinGW <br>
@@ -36,6 +42,15 @@ class Toolchain_mingw : public BaseToolchain {
   Toolchain_mingw()
       : Toolchain(ToolchainId::MinGW, "gcc", "as", "gcc", "g++", "ar", "ld") {}
   Toolchain_mingw(const Toolchain_mingw &) = delete;
+
+private:
+  void UpdateConfig(ToolchainConfig &config) {
+    config.obj_ext = kMingwObjExt;
+    config.pch_header_ext = kMingwPchHeaderExt;
+    config.pch_compile_ext = kMingwPchCompileExt;
+    config.prefix_include_dir = kMingwPrefixIncludeDir;
+    config.prefix_lib_dir = kMingwPrefixLibDir;
+  }
 };
 
 } // namespace buildcc
diff --git a/buildcc/toolchains/include/toolchains/toolchain_msvc.h b/buildcc/toolchains/include/toolchains/toolchain_msvc.h
index f74a479d..6a5a8ceb 100644
--- a/buildcc/toolchains/include/toolchains/toolchain_msvc.h
+++ b/buildcc/toolchains/include/toolchains/toolchain_msvc.h
@@ -21,6 +21,13 @@
 
 namespace buildcc {
 
+constexpr const char *const kMsvcObjExt = ".obj";
+constexpr const char *const kMsvcPchHeaderExt = ".h";
+constexpr const char *const kMsvcPchCompileExt = ".pch";
+
+constexpr const char *const kMsvcPrefixIncludeDir = "/I";
+constexpr const char *const kMsvcPrefixLibDir = "/LIBPATH:";
+
 /**
  * @brief Generic GCC Toolchain <br>
  * id = ToolchainId::Msvc <br>
@@ -37,6 +44,15 @@ class Toolchain_msvc : public Toolchain {
       : Toolchain(Toolchain::Id::Msvc, "msvc", "cl", "cl", "cl", "lib",
                   "link") {}
   Toolchain_msvc(const Toolchain_msvc &gcc) = delete;
+
+private:
+  void UpdateConfig(ToolchainConfig &config) {
+    config.obj_ext = kMsvcObjExt;
+    config.pch_header_ext = kMsvcPchHeaderExt;
+    config.pch_compile_ext = kMsvcPchCompileExt;
+    config.prefix_include_dir = kMsvcPrefixIncludeDir;
+    config.prefix_lib_dir = kMsvcPrefixLibDir;
+  }
 };
 
 } // namespace buildcc
diff --git a/buildexe/src/build_env_setup.cpp b/buildexe/src/build_env_setup.cpp
index 6884a1de..2bfcac96 100644
--- a/buildexe/src/build_env_setup.cpp
+++ b/buildexe/src/build_env_setup.cpp
@@ -194,31 +194,15 @@ struct BuildExeLibDir {{
   }
 
   // Segregate valid lib files into sources and include dirs
-  internal::fs_unordered_set sources;
-  internal::fs_unordered_set include_dirs;
-  internal::fs_unordered_set headers;
   for (const auto &lib_build_file : buildexe_args_.GetLibBuildFiles()) {
-    if (user_target.GetConfig().IsValidSource(lib_build_file)) {
-      sources.insert(lib_build_file);
+    if (user_target.GetToolchain().GetConfig().IsValidSource(lib_build_file)) {
+      user_target.AddSourceAbsolute(lib_build_file);
     }
-    if (user_target.GetConfig().IsValidHeader(lib_build_file)) {
-      include_dirs.insert(lib_build_file.parent_path());
-      headers.insert(lib_build_file);
+    if (user_target.GetToolchain().GetConfig().IsValidHeader(lib_build_file)) {
+      user_target.AddIncludeDirAbsolute(lib_build_file.parent_path(), false);
+      user_target.AddHeaderAbsolute(lib_build_file);
     }
   }
-
-  // Add sources to user_target
-  for (const auto &s : sources) {
-    user_target.AddSourceAbsolute(s);
-  }
-  // Add include dirs to user_target
-  for (const auto &idir : include_dirs) {
-    user_target.AddIncludeDir(idir, false);
-  }
-  // Add headers to user_target
-  for (const auto &h : headers) {
-    user_target.AddHeaderAbsolute(h);
-  }
 }
 
 void BuildEnvSetup::UserTargetBuild() {
diff --git a/doc/software_architecture/buildcc_interface_lib.PNG b/doc/software_architecture/buildcc_interface_lib.PNG
index 729c9b08..e0ce861c 100644
Binary files a/doc/software_architecture/buildcc_interface_lib.PNG and b/doc/software_architecture/buildcc_interface_lib.PNG differ
diff --git a/docs/source/arch/software_heirarchy.rst b/docs/source/arch/software_heirarchy.rst
index 5dfa8e9f..20877103 100644
--- a/docs/source/arch/software_heirarchy.rst
+++ b/docs/source/arch/software_heirarchy.rst
@@ -66,13 +66,12 @@ BuildCC interface lib
    taskflow -up-> register
 
    flatbuffers .up.> schema
-
-   env -up-> toolchain
    env -up-> schema
 
-   taskflow -up-> target
-   schema -up-> target
+   schema -up-> toolchain
+
    toolchain -up-> target
+   taskflow -up-> target
 
    toolchain -up-> toolchain_specialized
    target -up-> target_specialized
diff --git a/docs/source/user_api/target_utils.rst b/docs/source/user_api/target_utils.rst
index b85fc251..4940883f 100644
--- a/docs/source/user_api/target_utils.rst
+++ b/docs/source/user_api/target_utils.rst
@@ -3,11 +3,6 @@ Target Utils
 
 Commonly used Utils (Classes / Structs) for **Generator**, **TargetInfo** and **Target** classes.
 
-target_file_ext.h
-------------------
-
-.. doxygenenum:: buildcc::TargetFileExt
-
 target_type.h
 --------------
 
diff --git a/docs/source/user_api/toc.rst b/docs/source/user_api/toc.rst
index c149c8cd..c7c858d8 100644
--- a/docs/source/user_api/toc.rst
+++ b/docs/source/user_api/toc.rst
@@ -6,6 +6,7 @@ User API
 
     args
     register
+    toolchain_utils
     toolchain
     target_utils
     generator
diff --git a/docs/source/user_api/toolchain_utils.rst b/docs/source/user_api/toolchain_utils.rst
new file mode 100644
index 00000000..0e812633
--- /dev/null
+++ b/docs/source/user_api/toolchain_utils.rst
@@ -0,0 +1,14 @@
+Toolchain Utils
+================
+
+Commonly used Utils (Classes / Structs) for **Toolchain**
+
+file_ext.h
+------------
+
+.. doxygenenum:: buildcc::FileExt
+
+toolchain_config.h
+--------------------
+
+.. doxygenstruct:: buildcc::ToolchainConfig
diff --git a/example/hybrid/target_info/build.cpp b/example/hybrid/target_info/build.cpp
index 25aa1a4a..3fb2cf26 100644
--- a/example/hybrid/target_info/build.cpp
+++ b/example/hybrid/target_info/build.cpp
@@ -33,8 +33,10 @@ int main(int argc, char **argv) {
   Toolchain_msvc msvc;
 
   // TargetInfo
-  TargetInfo genericadd_ho("files");
-  reg.Callback(genericadd_ho_cb, genericadd_ho);
+  TargetInfo gcc_genericadd_ho(gcc, "files");
+  TargetInfo msvc_genericadd_ho(msvc, "files");
+  reg.Callback(genericadd_ho_cb, gcc_genericadd_ho);
+  reg.Callback(genericadd_ho_cb, msvc_genericadd_ho);
 
   ExecutableTarget_gcc g_genericadd1("generic_add_1", gcc, "files");
   ExecutableTarget_msvc m_genericadd1("generic_add_1", msvc, "files");
@@ -43,11 +45,15 @@ int main(int argc, char **argv) {
   ExecutableTarget_msvc m_genericadd2("generic_add_2", msvc, "files");
 
   // Select your builds and tests using the .toml files
-  reg.Build(arg_gcc.state, genericadd1_build_cb, g_genericadd1, genericadd_ho);
-  reg.Build(arg_msvc.state, genericadd1_build_cb, m_genericadd1, genericadd_ho);
-
-  reg.Build(arg_gcc.state, genericadd2_build_cb, g_genericadd2, genericadd_ho);
-  reg.Build(arg_msvc.state, genericadd2_build_cb, m_genericadd2, genericadd_ho);
+  reg.Build(arg_gcc.state, genericadd1_build_cb, g_genericadd1,
+            gcc_genericadd_ho);
+  reg.Build(arg_gcc.state, genericadd2_build_cb, g_genericadd2,
+            gcc_genericadd_ho);
+
+  reg.Build(arg_msvc.state, genericadd1_build_cb, m_genericadd1,
+            msvc_genericadd_ho);
+  reg.Build(arg_msvc.state, genericadd2_build_cb, m_genericadd2,
+            msvc_genericadd_ho);
 
   // 5. Test steps
   // NOTE, For now they are just dummy callbacks