diff --git a/benchmarks/message_pool_performance.cpp b/benchmarks/message_pool_performance.cpp
index c197baa..984d478 100644
--- a/benchmarks/message_pool_performance.cpp
+++ b/benchmarks/message_pool_performance.cpp
@@ -5,6 +5,11 @@
  * Phase D.2: Verify message pooling reduces allocation overhead
  */
 
+// KeystoneMessage::command is [[deprecated]]; benchmarks intentionally access
+// it to measure legacy-field allocation behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <benchmark/benchmark.h>
 
 #include <cstdint>
@@ -256,3 +261,5 @@ static void BM_MessageReset(benchmark::State& state) {
 BENCHMARK(BM_MessageReset);
 
 BENCHMARK_MAIN();
+
+#pragma GCC diagnostic pop
diff --git a/include/agents/lead_agent_base_impl.hpp b/include/agents/lead_agent_base_impl.hpp
index 3c450a3..eb55998 100644
--- a/include/agents/lead_agent_base_impl.hpp
+++ b/include/agents/lead_agent_base_impl.hpp
@@ -59,7 +59,10 @@ concurrency::Task<core::Response> LeadAgentBase<StateEnum>::processMessage(
   // Step 3: This is a new goal - decompose and delegate
   coordination_.transitionTo(planning_state_, stateToString(planning_state_));
 
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   coordination_.setCurrentGoal(msg.command);
+  _Pragma("GCC diagnostic pop")
   coordination_.setRequesterId(msg.sender_id);
 
   // Step 4: Decompose goal into subtasks (hook method - subclass implements)
diff --git a/include/core/message.hpp b/include/core/message.hpp
index c78cca3..bcb5a03 100644
--- a/include/core/message.hpp
+++ b/include/core/message.hpp
@@ -140,10 +140,22 @@ struct KeystoneMessage {
       correlation_id;  ///< Optional correlation ID for distributed tracing
 
   // Payload and timing
-  std::string command;  ///< Command string to execute (legacy/convenience)
-  std::optional<std::string> payload;               ///< Optional payload data
+  [[deprecated("command is a legacy/convenience field; use payload with ActionType instead")]]
+  std::string command;                 ///< Command string to execute (legacy/convenience)
+  std::optional<std::string> payload;  ///< Optional payload data
   std::chrono::system_clock::time_point timestamp;  ///< Message timestamp
 
+  // Declare special members out-of-line so their definitions (in message.cpp)
+  // can suppress -Wdeprecated-declarations for the internal move/copy of the
+  // deprecated 'command' field.  External code that reads/writes 'command'
+  // directly will still receive the deprecation diagnostic.
+  KeystoneMessage();
+  KeystoneMessage(const KeystoneMessage&);
+  KeystoneMessage(KeystoneMessage&&) noexcept;
+  KeystoneMessage& operator=(const KeystoneMessage&);
+  KeystoneMessage& operator=(KeystoneMessage&&) noexcept;
+  ~KeystoneMessage();
+
   /**
    * @brief Create a new message with generated ID (legacy interface)
    *
diff --git a/src/agents/component_lead_agent.cpp b/src/agents/component_lead_agent.cpp
index debf5ef..8d1f706 100644
--- a/src/agents/component_lead_agent.cpp
+++ b/src/agents/component_lead_agent.cpp
@@ -35,7 +35,11 @@ void ComponentLeadAgent::setAvailableModuleLeads(
 
 bool ComponentLeadAgent::isSubordinateResult(const core::KeystoneMessage& msg) {
   // Check if this is a module result
-  return msg.command == "module_result";
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+  bool result = msg.command == "module_result";
+  _Pragma("GCC diagnostic pop")
+  return result;
 }
 
 std::vector<std::string> ComponentLeadAgent::decomposeGoal(
diff --git a/src/agents/module_lead_agent.cpp b/src/agents/module_lead_agent.cpp
index f141011..2f43277 100644
--- a/src/agents/module_lead_agent.cpp
+++ b/src/agents/module_lead_agent.cpp
@@ -37,8 +37,12 @@ void ModuleLeadAgent::setAvailableTaskAgents(
 
 bool ModuleLeadAgent::isSubordinateResult(const core::KeystoneMessage& msg) {
   // Exclude TASK_FAILED so processSubordinateFailure() handles it instead
-  return msg.command == "response" &&
-         msg.action_type != core::ActionType::TASK_FAILED;
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+  bool result = msg.command == "response" &&
+                msg.action_type != core::ActionType::TASK_FAILED;
+  _Pragma("GCC diagnostic pop")
+  return result;
 }
 
 std::vector<std::string> ModuleLeadAgent::decomposeGoal(
diff --git a/src/agents/task_agent.cpp b/src/agents/task_agent.cpp
index 9e65b56..6d9a78e 100644
--- a/src/agents/task_agent.cpp
+++ b/src/agents/task_agent.cpp
@@ -76,6 +76,8 @@ concurrency::Task<core::Response> TaskAgent::processMessage(
 
   try {
     // Execute the bash command
+    _Pragma("GCC diagnostic push")
+    _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
     std::string result = executeBash(msg.command);
 
     // Log the execution (lock guards concurrent processMessage coroutines)
@@ -83,6 +85,7 @@ concurrency::Task<core::Response> TaskAgent::processMessage(
       std::lock_guard<std::mutex> lock(log_mutex_);
       command_log_.emplace_back(msg.command, result);
     }
+    _Pragma("GCC diagnostic pop")
 
     auto response = core::Response::createSuccess(msg, agent_id_, result);
     sendResponseMessage(msg, result);
diff --git a/src/agents/task_execution_strategy.cpp b/src/agents/task_execution_strategy.cpp
index ba63e4e..9d0582c 100644
--- a/src/agents/task_execution_strategy.cpp
+++ b/src/agents/task_execution_strategy.cpp
@@ -33,7 +33,10 @@ concurrency::Task<core::Response> TaskExecutionStrategy::process(
     const core::KeystoneMessage& msg) {
   try {
     // Execute the bash command
+    _Pragma("GCC diagnostic push")
+    _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
     std::string result = executeBashCommand(msg.command);
+    _Pragma("GCC diagnostic pop")
 
     // Create success response
     auto response = core::Response::createSuccess(msg, "strategy", result);
diff --git a/src/core/message.cpp b/src/core/message.cpp
index 6df836f..be505ed 100644
--- a/src/core/message.cpp
+++ b/src/core/message.cpp
@@ -7,6 +7,27 @@
 namespace keystone {
 namespace core {
 
+// ---------------------------------------------------------------------------
+// Out-of-line special-member definitions for KeystoneMessage.
+//
+// Defined here (rather than defaulted in the header) so that we can suppress
+// -Wdeprecated-declarations for the internal copy/move of the deprecated
+// 'command' field.  Callers that access 'command' directly still get the
+// warning.
+// ---------------------------------------------------------------------------
+_Pragma("GCC diagnostic push")
+_Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
+
+KeystoneMessage::KeystoneMessage() = default;
+KeystoneMessage::KeystoneMessage(const KeystoneMessage&) = default;
+KeystoneMessage::KeystoneMessage(KeystoneMessage&&) noexcept = default;
+KeystoneMessage& KeystoneMessage::operator=(const KeystoneMessage&) = default;
+KeystoneMessage& KeystoneMessage::operator=(KeystoneMessage&&) noexcept =
+    default;
+KeystoneMessage::~KeystoneMessage() = default;
+
+_Pragma("GCC diagnostic pop")
+
 namespace {
 // Simple UUID generation (not cryptographically secure, but sufficient for
 // Phase 1) Thread-safe: uses thread_local to avoid data races across threads
@@ -34,7 +55,10 @@ KeystoneMessage KeystoneMessage::create(
   msg.msg_id = generate_uuid();
   msg.sender_id = sender;
   msg.receiver_id = receiver;
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   msg.command = cmd;
+  _Pragma("GCC diagnostic pop")
   msg.payload = data;
   msg.timestamp = std::chrono::system_clock::now();
 
@@ -67,7 +91,10 @@ KeystoneMessage KeystoneMessage::create(const std::string& sender,
   msg.timestamp = std::chrono::system_clock::now();
 
   // Legacy field: set command based on action type
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   msg.command = actionTypeToString(action);
+  _Pragma("GCC diagnostic pop")
 
   // Phase C: Initialize priority and deadline (FIX: was missing!)
   msg.priority = Priority::NORMAL;
@@ -114,7 +141,10 @@ KeystoneMessage KeystoneMessage::createCancellation(
   msg.session_id = session;
   msg.task_id = task_id;          // Set the task to cancel
   msg.priority = Priority::HIGH;  // Cancellations are high priority
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   msg.command = "CANCEL_TASK";
+  _Pragma("GCC diagnostic pop")
   msg.timestamp = std::chrono::system_clock::now();
   return msg;
 }
diff --git a/src/core/message_pool.cpp b/src/core/message_pool.cpp
index b7a0552..97efc8f 100644
--- a/src/core/message_pool.cpp
+++ b/src/core/message_pool.cpp
@@ -45,7 +45,10 @@ void MessagePool::release(KeystoneMessage&& msg) {
   msg.msg_id.clear();
   msg.sender_id.clear();
   msg.receiver_id.clear();
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   msg.command.clear();
+  _Pragma("GCC diagnostic pop")
   msg.payload.reset();
   msg.priority = Priority::NORMAL;
   msg.deadline.reset();
diff --git a/src/core/message_serializer.cpp b/src/core/message_serializer.cpp
index 306a995..aa7c21d 100644
--- a/src/core/message_serializer.cpp
+++ b/src/core/message_serializer.cpp
@@ -28,7 +28,10 @@ SerializableMessage SerializableMessage::fromKeystoneMessage(
         cista::offset::string{value.c_str()};
   }
 
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   smsg.command = cista::offset::string{msg.command.c_str()};
+  _Pragma("GCC diagnostic pop")
 
   if (msg.payload.has_value()) {
     smsg.payload = cista::offset::string{msg.payload.value().c_str()};
@@ -73,7 +76,10 @@ KeystoneMessage SerializableMessage::toKeystoneMessage() const {
         std::string{value.data(), value.size()};
   }
 
+  _Pragma("GCC diagnostic push")
+  _Pragma("GCC diagnostic ignored \"-Wdeprecated-declarations\"")
   msg.command = std::string{command.data(), command.size()};
+  _Pragma("GCC diagnostic pop")
 
   if (has_payload) {
     msg.payload = std::string{payload.data(), payload.size()};
diff --git a/tests/e2e/component_coordination_test.cpp b/tests/e2e/component_coordination_test.cpp
index c28572f..2c9cc4b 100644
--- a/tests/e2e/component_coordination_test.cpp
+++ b/tests/e2e/component_coordination_test.cpp
@@ -15,6 +15,11 @@
  * - Full 4-layer message flow
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <memory>
@@ -248,3 +253,5 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/e2e/module_coordination_test.cpp b/tests/e2e/module_coordination_test.cpp
index 1cfd8aa..7485431 100644
--- a/tests/e2e/module_coordination_test.cpp
+++ b/tests/e2e/module_coordination_test.cpp
@@ -13,6 +13,11 @@
  * - Multi-agent coordination
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <memory>
@@ -264,3 +269,5 @@ int main(int argc, char** argv) {
   ::testing::InitGoogleTest(&argc, argv);
   return RUN_ALL_TESTS();
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/e2e/task_cancellation_test.cpp b/tests/e2e/task_cancellation_test.cpp
index 69c4419..5520e1d 100644
--- a/tests/e2e/task_cancellation_test.cpp
+++ b/tests/e2e/task_cancellation_test.cpp
@@ -11,6 +11,11 @@
  * 6. Parent receives acknowledgement
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <chrono>
@@ -271,3 +276,5 @@ TEST(E2E_TaskCancellation, MissingTaskIdReturnsError) {
   EXPECT_EQ(response.status, Response::Status::Error);
   EXPECT_TRUE(response.result.find("missing task_id") != std::string::npos);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/integration/test_registry_integration.cpp b/tests/integration/test_registry_integration.cpp
index dedd82e..073d190 100644
--- a/tests/integration/test_registry_integration.cpp
+++ b/tests/integration/test_registry_integration.cpp
@@ -14,6 +14,11 @@
  * - Edge cases (optional, 3-5 more tests)
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <atomic>
@@ -648,3 +653,5 @@ TEST_F(RegistryIntegrationTest, ClearRegistryClearsAll) {
     EXPECT_FALSE(bus_->hasAgent("agent_" + std::to_string(i)));
   }
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_agent_concepts.cpp b/tests/unit/test_agent_concepts.cpp
index 364cb7d..31863d4 100644
--- a/tests/unit/test_agent_concepts.cpp
+++ b/tests/unit/test_agent_concepts.cpp
@@ -9,6 +9,11 @@
  * - Compile-time errors for incomplete interfaces
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/chief_architect_agent.hpp"
@@ -316,3 +321,5 @@ TEST(AgentConcepts, UsageDocumentation) {
   EXPECT_TRUE(bus.hasAgent("task"));
   EXPECT_TRUE(bus.hasAgent("chief"));
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_agent_core.cpp b/tests/unit/test_agent_core.cpp
index a4f7368..30fba78 100644
--- a/tests/unit/test_agent_core.cpp
+++ b/tests/unit/test_agent_core.cpp
@@ -1,3 +1,8 @@
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 #include <spdlog/sinks/ringbuffer_sink.h>
 #include <spdlog/spdlog.h>
@@ -647,3 +652,5 @@ TEST(AgentCoreLogTest, BackpressureRecoveryLogsInfo) {
 
   keystone::concurrency::Logger::shutdown();
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_async_task_agent.cpp b/tests/unit/test_async_task_agent.cpp
index ceb9517..1fe600f 100644
--- a/tests/unit/test_async_task_agent.cpp
+++ b/tests/unit/test_async_task_agent.cpp
@@ -1,3 +1,8 @@
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <algorithm>
@@ -221,3 +226,5 @@ TEST_F(AsyncTaskAgentTest, FailedAgentRejectsMessages) {
   const auto& history = agent_->getCommandHistory();
   EXPECT_TRUE(history.empty());
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_chief_architect_agent.cpp b/tests/unit/test_chief_architect_agent.cpp
index f6141e1..cb6ea44 100644
--- a/tests/unit/test_chief_architect_agent.cpp
+++ b/tests/unit/test_chief_architect_agent.cpp
@@ -11,6 +11,11 @@
  * Total: 15 tests
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/chief_architect_agent.hpp"
@@ -279,3 +284,5 @@ TEST_F(ChiefArchitectAgentTest, ConcurrentStateAccess) {
   }
   EXPECT_EQ(count, 100);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_component_lead_agent.cpp b/tests/unit/test_component_lead_agent.cpp
index c0f6ed5..e0d1cb8 100644
--- a/tests/unit/test_component_lead_agent.cpp
+++ b/tests/unit/test_component_lead_agent.cpp
@@ -12,6 +12,11 @@
  * Total: 16 tests
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/component_lead_agent.hpp"
@@ -441,3 +446,5 @@ TEST_F(ComponentLeadAgentTest,
   auto state = component->getCurrentState();
   EXPECT_NE(state, agents::ComponentLeadAgent::State::WAITING_FOR_MODULES);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_interface_segregation.cpp b/tests/unit/test_interface_segregation.cpp
index d170c46..51d05da 100644
--- a/tests/unit/test_interface_segregation.cpp
+++ b/tests/unit/test_interface_segregation.cpp
@@ -7,6 +7,11 @@
  * Principle.
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/task_agent.hpp"
@@ -186,3 +191,5 @@ TEST(InterfaceSegregation, CompileTimeEnforcement) {
   // Now registry->registerAgent() works
   (void)registry;  // Suppress unused warning
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_lead_agent_base.cpp b/tests/unit/test_lead_agent_base.cpp
index 51602d3..9a88a6a 100644
--- a/tests/unit/test_lead_agent_base.cpp
+++ b/tests/unit/test_lead_agent_base.cpp
@@ -12,6 +12,11 @@
  * Total: 22 tests
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/lead_agent_base.hpp"
@@ -503,3 +508,5 @@ TEST_F(LeadAgentBaseTest, AllowsMultipleGoalProcessing) {
   // Second goal should be accepted
   EXPECT_TRUE(response2.success);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_message_bus_async.cpp b/tests/unit/test_message_bus_async.cpp
index 40477a4..cbf0434 100644
--- a/tests/unit/test_message_bus_async.cpp
+++ b/tests/unit/test_message_bus_async.cpp
@@ -3,6 +3,11 @@
  * @brief Tests for MessageBus with WorkStealingScheduler integration
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <atomic>
@@ -508,3 +513,5 @@ TEST(MessageBusAsyncTest, MessageToDeletedAgentGraceful) {
   // No crash = success
   SUCCEED();
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_message_pool.cpp b/tests/unit/test_message_pool.cpp
index b49d462..4667c16 100644
--- a/tests/unit/test_message_pool.cpp
+++ b/tests/unit/test_message_pool.cpp
@@ -1,3 +1,8 @@
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include <thread>
@@ -328,3 +333,5 @@ TEST_F(MessagePoolTest, MoveSemantics) {
   auto stats = MessagePool::getStats();
   EXPECT_EQ(stats.total_releases, 1);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_message_serializer.cpp b/tests/unit/test_message_serializer.cpp
index 37d458e..f57fcd0 100644
--- a/tests/unit/test_message_serializer.cpp
+++ b/tests/unit/test_message_serializer.cpp
@@ -3,6 +3,11 @@
  * @brief Unit tests for MessageSerializer (Cista-based)
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "core/message.hpp"
@@ -201,3 +206,5 @@ TEST(MessageSerializerTest, LegacyCreateCompatibility) {
   EXPECT_EQ(deserialized.content_type, ContentType::TEXT_PLAIN);
   EXPECT_EQ(deserialized.command, "echo hello");
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_module_lead_agent.cpp b/tests/unit/test_module_lead_agent.cpp
index 858743d..a5c96b6 100644
--- a/tests/unit/test_module_lead_agent.cpp
+++ b/tests/unit/test_module_lead_agent.cpp
@@ -11,6 +11,11 @@
  * Total: 12 tests
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/component_lead_agent.hpp"
@@ -522,3 +527,5 @@ TEST_F(ModuleLeadAgentTest, ConcurrentCoordination) {
   }
   EXPECT_EQ(count, 50);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_task_agent.cpp b/tests/unit/test_task_agent.cpp
index 1f8428a..ab1358e 100644
--- a/tests/unit/test_task_agent.cpp
+++ b/tests/unit/test_task_agent.cpp
@@ -11,6 +11,11 @@
  * Total: 15 tests
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/task_agent.hpp"
@@ -235,3 +240,5 @@ TEST_F(TaskAgentTest, HandleBusUnavailable) {
   // Sending without bus should throw
   EXPECT_THROW(agent->sendMessage(msg), std::runtime_error);
 }
+
+#pragma GCC diagnostic pop
diff --git a/tests/unit/test_task_cancellation.cpp b/tests/unit/test_task_cancellation.cpp
index e93c583..b6a6d70 100644
--- a/tests/unit/test_task_cancellation.cpp
+++ b/tests/unit/test_task_cancellation.cpp
@@ -9,6 +9,11 @@
  * - MessageBus routing of CANCEL_TASK messages
  */
 
+// KeystoneMessage::command is [[deprecated]]; test files intentionally access
+// it to verify backward-compat behaviour.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 #include <gtest/gtest.h>
 
 #include "agents/async_agent.hpp"
@@ -212,3 +217,5 @@ TEST(TaskCancellation, ThreadSafeCancellation) {
     EXPECT_TRUE(agent->isCancelled(task_id));
   }
 }
+
+#pragma GCC diagnostic pop