diff --git a/.gitignore b/.gitignore
index 7e53678..086cdb0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,9 @@
 .vscode/
 
 build/
+out/
 bin/
+
+.cache/
+compile_commands.json
+
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6393e5b..9fc5327 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -9,6 +9,7 @@ set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 find_package(protobuf CONFIG REQUIRED)
 find_package(gRPC CONFIG REQUIRED)
 find_package(fmt CONFIG REQUIRED)
+find_package(tomlplusplus CONFIG REQUIRED)
 
 set(PROTO_DIR ${CMAKE_SOURCE_DIR}/libs/proto)
 set(PROTO_FILE ${PROTO_DIR}/volta.proto)
@@ -23,15 +24,15 @@ set(GRPC_HDR "${CMAKE_CURRENT_BINARY_DIR}/volta.grpc.pb.h")
 
 add_custom_command(
     OUTPUT "${PROTO_SRC}" "${PROTO_HDR}" "${GRPC_SRC}" "${GRPC_HDR}"
-    
+
     COMMAND protobuf::protoc
-    
+
     ARGS --cpp_out="${CMAKE_CURRENT_BINARY_DIR}"
          --grpc_out="${CMAKE_CURRENT_BINARY_DIR}"
          --plugin=protoc-gen-grpc="${GRPC_CPP_PLUGIN}"
          -I "${PROTO_DIR}"
          "${PROTO_FILE}"
-         
+
     DEPENDS "${PROTO_FILE}" gRPC::grpc_cpp_plugin
     COMMENT "Generating C++ code from volta.proto..."
 )
@@ -40,11 +41,12 @@ add_library(volta_proto ${PROTO_SRC} ${PROTO_HDR} ${GRPC_SRC} ${GRPC_HDR})
 
 target_include_directories(volta_proto PUBLIC ${CMAKE_CURRENT_BINARY_DIR})
 
-target_link_libraries(volta_proto PRIVATE 
-  protobuf::libprotobuf 
+target_link_libraries(volta_proto PRIVATE
+  protobuf::libprotobuf
   gRPC::grpc++
   gRPC::grpc++_reflection
   fmt::fmt
+  tomlplusplus::tomlplusplus
   ${CMAKE_DL_LIBS}
 )
 
@@ -64,7 +66,7 @@ if(CLANG_FORMAT_EXE)
         COMMENT "Running clang-format on source files..."
         VERBATIM
     )
-    
+
     # optional: check formatting
     add_custom_target(check-format
         COMMAND find source/agent -name "*.cc" -o -name "*.h" | xargs ${CLANG_FORMAT_EXE} --dry-run --Werror -style=Google
diff --git a/agent.conf b/agent.conf
new file mode 100644
index 0000000..a80c3bc
--- /dev/null
+++ b/agent.conf
@@ -0,0 +1 @@
+core_affinity = [2, "3-10"]
diff --git a/source/agent/CMakeLists.txt b/source/agent/CMakeLists.txt
index 46a770a..bb23533 100644
--- a/source/agent/CMakeLists.txt
+++ b/source/agent/CMakeLists.txt
@@ -1,6 +1,11 @@
 set(AGENT_NAME volta_agent)
 add_executable(${AGENT_NAME})
 
+if(CMAKE_BUILD_TYPE STREQUAL "Debug")
+    message(STATUS "Debug build - adding DEBUG macro")
+    target_compile_definitions(${AGENT_NAME} PRIVATE DEBUG)
+endif()
+
 file(GLOB_RECURSE AGENT_SOURCES "src/*.cc")
 target_sources(${AGENT_NAME} PRIVATE ${AGENT_SOURCES})
 
@@ -11,9 +16,14 @@ target_link_libraries(${AGENT_NAME} PRIVATE volta_proto)
 find_package(Threads REQUIRED)
 find_package(Protobuf REQUIRED)
 find_package(gRPC REQUIRED)
+find_package(tomlplusplus REQUIRED)
 
-target_link_libraries(${AGENT_NAME} PRIVATE Threads::Threads)
-target_link_libraries(${AGENT_NAME} PRIVATE gRPC::grpc++ protobuf::libprotobuf)
+target_link_libraries(${AGENT_NAME} PRIVATE
+    Threads::Threads
+    gRPC::grpc++
+    protobuf::libprotobuf
+    tomlplusplus::tomlplusplus
+)
 
 find_path(NVML_INCLUDE_DIR nvml.h
     PATHS ${CMAKE_SOURCE_DIR}/libs/include/nvidia
@@ -30,7 +40,6 @@ if(NVML_INCLUDE_DIR AND NVML_LIBRARY)
     target_include_directories(${AGENT_NAME} PRIVATE ${NVML_INCLUDE_DIR})
     target_link_libraries(${AGENT_NAME} PRIVATE ${NVML_LIBRARY})
     target_compile_definitions(${AGENT_NAME} PRIVATE HAVE_NVML)
-
 else()
     message(STATUS "NVML library not found. Using STUB for compilation.")
     add_library(nvml_stub STATIC ${CMAKE_SOURCE_DIR}/libs/stubs/nvml_stub.cc)
@@ -40,5 +49,11 @@ else()
     target_include_directories(${AGENT_NAME} PRIVATE ${CMAKE_SOURCE_DIR}/libs/include/nvidia)
 endif()
 
+configure_file(
+    ${CMAKE_SOURCE_DIR}/agent.conf
+    ${CMAKE_CURRENT_BINARY_DIR}/agent.conf
+    COPYONLY
+)
+
 # 5. TODO: find rocm_smi and oneapi level_zero
 # 6. TODO: find PMU (libpfm)
diff --git a/source/agent/src/config/config.h b/source/agent/src/config/config.h
index 1a83a7c..7af79da 100644
--- a/source/agent/src/config/config.h
+++ b/source/agent/src/config/config.h
@@ -1,10 +1,14 @@
 #ifndef VOLTA_AGENT_CONFIG_CONFIG_H_
 #define VOLTA_AGENT_CONFIG_CONFIG_H_
 
+#include <sched.h>
+
 #include <chrono>
 #include <cstdint>
+#include <iostream>
 #include <map>
 #include <string>
+#include <thread>
 
 namespace volta {
 namespace agent {
@@ -39,14 +43,40 @@ struct CollectorConfig {
 };
 
 struct Config {
+  void PrintCurrentAffinity() {
+    cpu_set_t set;
+    CPU_ZERO(&set);
+
+    if (sched_getaffinity(0, sizeof(set), &set) != 0) {
+      perror("sched_getaffinity");
+      return;
+    }
+
+    long max_cpus = sysconf(_SC_NPROCESSORS_CONF);
+    std::cout << "Current CPU affinity: ";
+
+    for (int i = 0; i < max_cpus; ++i) {
+      if (CPU_ISSET(i, &set)) std::cout << i << " ";
+    }
+    std::cout << "\n";
+  }
+
   static constexpr int32_t kDefaultIntervalMs = 500;
-  static constexpr int32_t kDefaultAffinity = -1;
   static constexpr char const* kDefaultServerAddress = "localhost";
   static constexpr uint16_t kDefaultServerPort = 50051;
+  static inline cpu_set_t kDefaultAffinity = [] {
+    cpu_set_t mask;
+    CPU_ZERO(&mask);
+    unsigned int n_cpus = std::thread::hardware_concurrency();
+    for (unsigned int i = 0; i < n_cpus; ++i) {
+      CPU_SET(i, &mask);
+    }
+    return mask;
+  }();
 
   std::chrono::milliseconds collection_interval =
       std::chrono::milliseconds(kDefaultIntervalMs);
-  int32_t core_affinity = kDefaultAffinity;
+  cpu_set_t core_affinity = kDefaultAffinity;
 
   std::string server_address = kDefaultServerAddress;
   uint16_t server_port = kDefaultServerPort;
diff --git a/source/agent/src/config/config_loader.cc b/source/agent/src/config/config_loader.cc
index d409213..3c846ee 100644
--- a/source/agent/src/config/config_loader.cc
+++ b/source/agent/src/config/config_loader.cc
@@ -1,10 +1,37 @@
 #include "config/config_loader.h"
 
+#include <sched.h>
+
+#include <filesystem>
+#include <iostream>
+#include <toml++/toml.hpp>
+
+#include "config/config.h"
+
 namespace volta {
 namespace agent {
 namespace config {
 
+std::filesystem::path ConfigLoader::kConfigFile = "agent.conf";
+
+std::set<std::string> ConfigLoader::kValidTopLevelKeys = {
+    "core_affinity",  "core_affinity_mask", "interval",
+    "server_address", "server_port",        "collectors"};
+
+std::map<std::string, std::set<std::string>>
+    ConfigLoader::kValidCollectorMetrics = {
+        {"cpu", {"proc_stat", "cpu_freq", "rapl", "zenpower", "pmu"}},
+        {"gpu", {"nvml", "dcgm", "rocm", "level_zero"}},
+        {"ram", {"mem_info", "vm_stat"}},
+        {"io", {"disk_stats", "net_dev"}}};
+
 Config ConfigLoader::LoadConfig() {
+  Config config = LoadDefaultConfig();
+  LoadConfigFile(config);
+  return config;
+}
+
+Config ConfigLoader::LoadDefaultConfig() {
   Config config;
 
   CollectorConfig nvml_collector;
@@ -24,9 +51,111 @@ Config ConfigLoader::LoadConfig() {
   return config;
 }
 
-Config ConfigLoader::LoadConfig(const std::filesystem::path& filepath) {
-  // ignore for POC
-  return LoadConfig();
+inline unsigned int MaxOnlineCpus() {
+  long n = sysconf(_SC_NPROCESSORS_ONLN);
+  return (n > 0) ? static_cast<unsigned int>(n) : 0;
+}
+
+bool AddCpu(cpu_set_t& set, unsigned int cpu, unsigned int max_cpu) {
+  if (cpu >= max_cpu) return false;
+  CPU_SET(cpu, &set);
+  return true;
+}
+
+bool AddRange(cpu_set_t& set, unsigned int from, unsigned int to,
+              unsigned int max_cpu) {
+  if (from > to || to >= max_cpu) return false;
+  for (unsigned int i = from; i <= to; ++i) CPU_SET(i, &set);
+  return true;
+}
+
+void ConfigLoader::LoadConfigFile(Config& out_config) {
+  if (!std::filesystem::exists(kConfigFile)) {
+    std::cout << "Agent config file not found, loading default settings."
+              << std::endl;
+    return;
+  }
+
+  try {
+    toml::table tbl = toml::parse_file(kConfigFile.string());
+
+    if (auto val = tbl["core_affinity"]) {
+      unsigned int max_cpu = MaxOnlineCpus();
+      cpu_set_t mask;
+      CPU_ZERO(&mask);
+
+      // core_affinity = "all"
+      if (auto s = val.value<std::string>(); s && *s == "all") {
+        for (unsigned int i = 0; i < max_cpu; ++i) CPU_SET(i, &mask);
+
+        out_config.core_affinity = mask;
+      }
+      // core_affinity = [ ... ]
+      else if (auto arr = val.as_array()) {
+        for (auto& item : *arr) {
+          // liczba CPU
+          if (auto cpu = item.value<unsigned int>()) {
+            if (!AddCpu(mask, *cpu, max_cpu)) {
+              std::cerr << "CPU index out of range: " << *cpu << "\n";
+              return;
+            }
+          }
+          // zakres "X-Y"
+          else if (auto str = item.value<std::string>()) {
+            unsigned int from, to;
+            if (sscanf(str->c_str(), "%u-%u", &from, &to) == 2) {
+              if (!AddRange(mask, from, to, max_cpu)) {
+                std::cerr << "Invalid CPU range: " << *str << "\n";
+                return;
+              }
+            } else {
+              std::cerr << "Invalid core_affinity entry: " << *str << "\n";
+              return;
+            }
+          } else {
+            std::cerr << "Invalid core_affinity element type\n";
+            return;
+          }
+        }
+        if (sched_setaffinity(0, sizeof(cpu_set_t), &mask) == -1) {
+          perror("sched_setaffinity");
+        } else {
+          std::cout << "Successfully set CPU affinity mask." << std::endl;
+        }
+        out_config.core_affinity = mask;
+      } else {
+        std::cerr << "Invalid core_affinity value\n";
+      }
+    }
+    // interval
+    // server_address
+    // server_port
+
+    auto collectors_node = tbl["collectors"].as_table();
+    if (!collectors_node) return;
+
+    for (auto& [collector_name, collector_node] : *collectors_node) {
+      auto collector_table = collector_node.as_table();
+      if (!collector_table) continue;
+
+      CollectorConfig collector;
+
+      if (auto enabled_array = (*collector_table)["enabled"].as_array()) {
+        for (auto& item : *enabled_array) {
+          if (auto str = item.value<std::string>()) {
+            collector.metrics[*str] = true;
+          }
+        }
+
+        collector.enabled = !collector.metrics.empty();
+      }
+
+      out_config.collectors[std::string{collector_name.str()}] = collector;
+    }
+  } catch (const toml::parse_error& err) {
+    std::cerr << "Parsing Agent config failed: " << err.description() << " at "
+              << err.source().begin << std::endl;
+  }
 }
 
 }  // namespace config
diff --git a/source/agent/src/config/config_loader.h b/source/agent/src/config/config_loader.h
index c683c35..4e70ca5 100644
--- a/source/agent/src/config/config_loader.h
+++ b/source/agent/src/config/config_loader.h
@@ -2,7 +2,8 @@
 #define VOLTA_AGENT_CONFIG_CONFIG_LOADER_H_
 
 #include <filesystem>
-#include <string>
+#include <map>
+#include <set>
 
 #include "config/config.h"
 
@@ -13,9 +14,16 @@ namespace config {
 class ConfigLoader {
  public:
   static Config LoadConfig();
-  static Config LoadConfig(const std::filesystem::path& filepath);
 
  private:
+  ConfigLoader() = delete;
+
+  static Config LoadDefaultConfig();
+  static void LoadConfigFile(Config& out_config);
+
+  static std::filesystem::path kConfigFile;
+  static std::set<std::string> kValidTopLevelKeys;
+  static std::map<std::string, std::set<std::string>> kValidCollectorMetrics;
 };
 
 }  // namespace config
diff --git a/source/agent/src/platform/platform_detector.cc b/source/agent/src/platform/platform_detector.cc
index 243f11d..f0ebb48 100644
--- a/source/agent/src/platform/platform_detector.cc
+++ b/source/agent/src/platform/platform_detector.cc
@@ -123,7 +123,7 @@ std::string PlatformDetector::DetectOS() {
 
   std::string line;
   while (std::getline(file, line)) {
-    if (line.starts_with("PRETTY_NAME=") == 0) {
+    if (line.starts_with("PRETTY_NAME=")) {
       std::string value = line.substr(12);
 
       if (value.size() >= 2 && value.front() == '"' && value.back() == '"') {
diff --git a/vcpkg.json b/vcpkg.json
index fb12fdb..f7b4c46 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -5,6 +5,7 @@
   "dependencies": [
     "fmt",
     "grpc",
-    "protobuf"
+    "protobuf",
+    "tomlplusplus"
   ]
 }