diff --git a/src/test/rpc/RuntimeConfig_test.cpp b/src/test/rpc/RuntimeConfig_test.cpp
index 307e2604d..ebdbc50f9 100644
--- a/src/test/rpc/RuntimeConfig_test.cpp
+++ b/src/test/rpc/RuntimeConfig_test.cpp
@@ -22,10 +22,37 @@
 #include <xrpld/overlay/detail/TrafficCount.h>
 #include <xrpl/protocol/jss.h>
 
+#include <cstdlib>
+#include <optional>
+#include <string>
+
 namespace ripple {
 
 class RuntimeConfig_test : public beast::unit_test::suite
 {
+    class EnvVarGuard
+    {
+    public:
+        EnvVarGuard(char const* name, char const* value) : name_(name)
+        {
+            if (auto const* old = std::getenv(name))
+                old_ = old;
+            setenv(name, value, 1);
+        }
+
+        ~EnvVarGuard()
+        {
+            if (old_)
+                setenv(name_, old_->c_str(), 1);
+            else
+                unsetenv(name_);
+        }
+
+    private:
+        char const* name_;
+        std::optional<std::string> old_;
+    };
+
     // Helper to call runtime_config RPC with JSON params
     Json::Value
     runtimeConfig(test::jtx::Env& env, Json::Value const& params)
@@ -265,6 +292,71 @@ class RuntimeConfig_test : public beast::unit_test::suite
         BEAST_EXPECT(!cfg->appliesTo(TrafficCount::category::base));
     }
 
+    void
+    testMessageTypeAliases()
+    {
+        testcase("Message type aliases expand to multiple categories");
+        using namespace test::jtx;
+        Env env{*this};
+
+        Json::Value params;
+        params["set"] = Json::objectValue;
+        params["set"]["*"] = Json::objectValue;
+        params["set"]["*"]["send_delay_ms"] = 100;
+        params["set"]["*"]["message_types"] = Json::arrayValue;
+        params["set"]["*"]["message_types"].append("candidate_set_fetch");
+        auto result = runtimeConfig(env, params);
+
+        auto const& global = result["configs"]["*"];
+        BEAST_EXPECT(global.isMember("message_types"));
+        BEAST_EXPECT(global["message_types"].size() == 4);
+
+        auto cfg = env.app().getRuntimeConfig().getConfig("*");
+        if (!BEAST_EXPECT(cfg.has_value()))
+            return;
+
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::gl_tsc_get));
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::gl_tsc_share));
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::ld_tsc_get));
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::ld_tsc_share));
+        BEAST_EXPECT(!cfg->appliesTo(TrafficCount::category::proposal));
+    }
+
+    void
+    testEnvMessageTypeFilter()
+    {
+        testcase("XAHAU_RUNTIME_CONFIG parses message_types");
+
+        EnvVarGuard guard{
+            "XAHAU_RUNTIME_CONFIG",
+            R"({"*":{"send_delay_ms":100,"message_types":["candidate_set_fetch"]}})"};
+
+        RuntimeConfig rc;
+        auto cfg = rc.getConfig("*");
+        if (!BEAST_EXPECT(cfg.has_value()))
+            return;
+
+        BEAST_EXPECT(rc.active());
+        BEAST_EXPECT(cfg->sendDelayMs == 100);
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::gl_tsc_get));
+        BEAST_EXPECT(cfg->appliesTo(TrafficCount::category::ld_tsc_share));
+        BEAST_EXPECT(!cfg->appliesTo(TrafficCount::category::proposal));
+    }
+
+    void
+    testInvalidEnvMessageType()
+    {
+        testcase("Invalid XAHAU_RUNTIME_CONFIG message_types are ignored");
+
+        EnvVarGuard guard{
+            "XAHAU_RUNTIME_CONFIG",
+            R"({"*":{"send_delay_ms":100,"message_types":["not_a_category"]}})"};
+
+        RuntimeConfig rc;
+        BEAST_EXPECT(!rc.active());
+        BEAST_EXPECT(!rc.getConfig("*").has_value());
+    }
+
     void
     testMessageTypeFilterEmpty()
     {
@@ -313,6 +405,25 @@ class RuntimeConfig_test : public beast::unit_test::suite
         BEAST_EXPECT(!env.app().getRuntimeConfig().active());
     }
 
+    void
+    testInvalidMessageTypesShape()
+    {
+        testcase("Non-array message_types returns error");
+        using namespace test::jtx;
+        Env env{*this};
+
+        Json::Value params;
+        params["set"] = Json::objectValue;
+        params["set"]["*"] = Json::objectValue;
+        params["set"]["*"]["send_delay_ms"] = 100;
+        params["set"]["*"]["message_types"] = "proposal";
+        auto result = runtimeConfig(env, params);
+
+        BEAST_EXPECT(result.isMember("error"));
+        BEAST_EXPECT(result["error"].asString() == "invalidParams");
+        BEAST_EXPECT(!env.app().getRuntimeConfig().active());
+    }
+
     void
     testDropPctClamping()
     {
@@ -515,8 +626,12 @@ public:
         testClearAll();
         testPerPeerWithoutGlobal();
         testMessageTypeFilter();
+        testMessageTypeAliases();
+        testEnvMessageTypeFilter();
+        testInvalidEnvMessageType();
         testMessageTypeFilterEmpty();
         testInvalidMessageType();
+        testInvalidMessageTypesShape();
         testDropPctClamping();
         testRngClaimDropPct();
         testRngClaimDropPctClamping();
diff --git a/src/xrpld/app/misc/RuntimeConfig.h b/src/xrpld/app/misc/RuntimeConfig.h
index 5a65f04b1..9543aa4d5 100644
--- a/src/xrpld/app/misc/RuntimeConfig.h
+++ b/src/xrpld/app/misc/RuntimeConfig.h
@@ -26,6 +26,7 @@
 #include <shared_mutex>
 #include <string>
 #include <unordered_map>
+#include <vector>
 
 namespace ripple {
 
@@ -177,6 +178,22 @@ private:
     std::unordered_map<std::string, ConfigVals> merged_;
 };
 
+/** Expand runtime-config message type names into TrafficCount categories.
+
+    Names are intentionally string-based so test tools can target overlay
+    traffic without depending on enum values.  Aliases may expand to several
+    categories, for example candidate-set fetch covers the TMGetLedger request
+    and TMLedgerData reply categories used by tx-set and sidecar acquisition.
+*/
+std::optional<std::set<std::size_t>>
+runtimeConfigMessageCategoriesFromNames(
+    std::vector<std::string> const& names,
+    std::string& error);
+
+/** Human-readable name for one runtime-config message category. */
+std::string
+runtimeConfigMessageCategoryName(std::size_t category);
+
 }  // namespace ripple
 
 #endif
diff --git a/src/xrpld/app/misc/detail/RuntimeConfig.cpp b/src/xrpld/app/misc/detail/RuntimeConfig.cpp
index c5887011e..3da5e1342 100644
--- a/src/xrpld/app/misc/detail/RuntimeConfig.cpp
+++ b/src/xrpld/app/misc/detail/RuntimeConfig.cpp
@@ -18,6 +18,7 @@
 //==============================================================================
 
 #include <xrpld/app/misc/RuntimeConfig.h>
+#include <xrpld/overlay/detail/TrafficCount.h>
 
 #include <xrpl/json/json_reader.h>
 #include <xrpl/json/json_value.h>
@@ -25,12 +26,148 @@
 #include <algorithm>
 #include <cctype>
 #include <cstdlib>
+#include <exception>
 #include <mutex>
+#include <optional>
+#include <set>
 #include <string>
+#include <vector>
 
 namespace ripple {
 
 namespace {
+using CategorySet = std::set<std::size_t>;
+
+struct CategoryAlias
+{
+    char const* name;
+    std::vector<std::size_t> categories;
+};
+
+std::vector<CategoryAlias> const&
+categoryAliases()
+{
+    using C = TrafficCount::category;
+    static std::vector<CategoryAlias> const aliases = {
+        {"base", {C::base}},
+        {"cluster", {C::cluster}},
+        {"overlay", {C::overlay}},
+        {"proposal", {C::proposal}},
+        {"validation", {C::validation}},
+        {"transaction", {C::transaction}},
+        {"manifests", {C::manifests}},
+        {"validator_list", {C::validatorlist}},
+        {"validatorlist", {C::validatorlist}},
+
+        {"have_set", {C::get_set, C::share_set}},
+        {"set_get", {C::get_set}},
+        {"set_share", {C::share_set}},
+
+        {"candidate_set_fetch",
+         {C::gl_tsc_get, C::gl_tsc_share, C::ld_tsc_get, C::ld_tsc_share}},
+        {"candidate_set_request", {C::gl_tsc_get}},
+        {"candidate_set_reply", {C::ld_tsc_share}},
+
+        {"ledger_data",
+         {C::ld_tsc_get,
+          C::ld_tsc_share,
+          C::ld_txn_get,
+          C::ld_txn_share,
+          C::ld_asn_get,
+          C::ld_asn_share,
+          C::ld_get,
+          C::ld_share}},
+        {"ledger_data_tsc_get", {C::ld_tsc_get}},
+        {"ledger_data_tsc_share", {C::ld_tsc_share}},
+        {"ledger_data_txn_get", {C::ld_txn_get}},
+        {"ledger_data_txn_share", {C::ld_txn_share}},
+        {"ledger_data_asn_get", {C::ld_asn_get}},
+        {"ledger_data_asn_share", {C::ld_asn_share}},
+        {"ledger_data_get", {C::ld_get}},
+        {"ledger_data_share", {C::ld_share}},
+
+        {"get_ledger",
+         {C::gl_tsc_get,
+          C::gl_tsc_share,
+          C::gl_txn_get,
+          C::gl_txn_share,
+          C::gl_asn_get,
+          C::gl_asn_share,
+          C::gl_get,
+          C::gl_share}},
+        {"get_ledger_tsc_get", {C::gl_tsc_get}},
+        {"get_ledger_tsc_share", {C::gl_tsc_share}},
+        {"get_ledger_txn_get", {C::gl_txn_get}},
+        {"get_ledger_txn_share", {C::gl_txn_share}},
+        {"get_ledger_asn_get", {C::gl_asn_get}},
+        {"get_ledger_asn_share", {C::gl_asn_share}},
+        {"get_ledger_get", {C::gl_get}},
+        {"get_ledger_share", {C::gl_share}},
+
+        {"get_object",
+         {C::share_hash_ledger,
+          C::get_hash_ledger,
+          C::share_hash_tx,
+          C::get_hash_tx,
+          C::share_hash_txnode,
+          C::get_hash_txnode,
+          C::share_hash_asnode,
+          C::get_hash_asnode,
+          C::share_cas_object,
+          C::get_cas_object,
+          C::share_fetch_pack,
+          C::get_fetch_pack,
+          C::get_transactions,
+          C::share_hash,
+          C::get_hash}},
+        {"get_object_fetch_pack", {C::share_fetch_pack, C::get_fetch_pack}},
+        {"get_object_fetch_pack_get", {C::get_fetch_pack}},
+        {"get_object_fetch_pack_share", {C::share_fetch_pack}},
+        {"get_object_get", {C::get_hash}},
+        {"get_object_share", {C::share_hash}},
+        {"get_object_transactions", {C::get_transactions}},
+
+        {"proof_path", {C::proof_path_request, C::proof_path_response}},
+        {"proof_path_request", {C::proof_path_request}},
+        {"proof_path_response", {C::proof_path_response}},
+        {"replay_delta", {C::replay_delta_request, C::replay_delta_response}},
+        {"replay_delta_request", {C::replay_delta_request}},
+        {"replay_delta_response", {C::replay_delta_response}},
+        {"have_transactions", {C::have_transactions}},
+        {"requested_transactions", {C::requested_transactions}},
+    };
+    return aliases;
+}
+
+std::optional<CategorySet>
+categoriesForName(std::string const& name)
+{
+    for (auto const& alias : categoryAliases())
+    {
+        if (name == alias.name)
+            return CategorySet{
+                alias.categories.begin(), alias.categories.end()};
+    }
+
+    if (!name.empty() &&
+        std::all_of(name.begin(), name.end(), [](unsigned char c) {
+            return std::isdigit(c);
+        }))
+    {
+        try
+        {
+            auto const cat = static_cast<std::size_t>(std::stoull(name));
+            if (cat <= TrafficCount::category::unknown)
+                return CategorySet{cat};
+        }
+        catch (std::exception const&)
+        {
+        }
+    }
+
+    return std::nullopt;
+}
+
 std::optional<bool>
 parseBoolEnv(char const* env)
 {
@@ -51,7 +188,7 @@ parseBoolEnv(char const* env)
     return std::nullopt;
 }
 
-ConfigVals
+std::optional<ConfigVals>
 parseConfigVals(Json::Value const& v)
 {
     ConfigVals cfg;
@@ -73,10 +210,56 @@ parseConfigVals(Json::Value const& v)
         cfg.rngPollMs = std::max(50, v["rng_poll_ms"].asInt());
     if (v.isMember("no_export_sig"))
         cfg.noExportSig = v["no_export_sig"].asBool();
+    if (v.isMember("message_types"))
+    {
+        if (!v["message_types"].isArray())
+            return std::nullopt;
+
+        std::vector<std::string> names;
+        for (auto const& mt : v["message_types"])
+            names.push_back(mt.asString());
+
+        std::string error;
+        auto cats = runtimeConfigMessageCategoriesFromNames(names, error);
+        if (!cats)
+            return std::nullopt;
+        cfg.messageCategories = *cats;
+    }
     return cfg;
 }
 }  // namespace
 
+std::optional<std::set<std::size_t>>
+runtimeConfigMessageCategoriesFromNames(
+    std::vector<std::string> const& names,
+    std::string& error)
+{
+    CategorySet result;
+    for (auto const& name : names)
+    {
+        auto cats = categoriesForName(name);
+        if (!cats)
+        {
+            error = "Unknown message_type: " + name;
+            return std::nullopt;
+        }
+        result.insert(cats->begin(), cats->end());
+    }
+    return result;
+}
+
+std::string
+runtimeConfigMessageCategoryName(std::size_t category)
+{
+    for (auto const& alias : categoryAliases())
+    {
+        if (alias.categories.size() == 1 &&
+            alias.categories.front() == category)
+            return alias.name;
+    }
+    return std::to_string(category);
+}
+
 RuntimeConfig::RuntimeConfig()
 {
     // XAHAU_RUNTIME_CONFIG takes precedence (full JSON config)
@@ -88,7 +271,10 @@ RuntimeConfig::RuntimeConfig()
         {
             std::unique_lock lock(mutex_);
             for (auto const& target : root.getMemberNames())
-                configs_[target] = parseConfigVals(root[target]);
+            {
+                if (auto cfg = parseConfigVals(root[target]))
+                    configs_[target] = *cfg;
+            }
             rebuildMerged();
             updateActive();
         }
diff --git a/src/xrpld/rpc/handlers/RuntimeConfig.cpp b/src/xrpld/rpc/handlers/RuntimeConfig.cpp
index c4ed393d4..54123451e 100644
--- a/src/xrpld/rpc/handlers/RuntimeConfig.cpp
+++ b/src/xrpld/rpc/handlers/RuntimeConfig.cpp
@@ -19,49 +19,12 @@
 
 #include <xrpld/app/main/Application.h>
 #include <xrpld/app/misc/RuntimeConfig.h>
-#include <xrpld/overlay/detail/TrafficCount.h>
 #include <xrpld/rpc/Context.h>
 
+#include <vector>
+
 namespace ripple {
 
-namespace {
-// Map user-friendly names to TrafficCount::category values.
-// Only the commonly useful categories are exposed; extend as needed.
-std::optional<std::size_t>
-categoryFromName(std::string const& name)
-{
-    static std::unordered_map<std::string, std::size_t> const map = {
-        {"proposal", TrafficCount::category::proposal},
-        {"validation", TrafficCount::category::validation},
-        {"transaction", TrafficCount::category::transaction},
-        {"manifests", TrafficCount::category::manifests},
-        {"ledger_data", TrafficCount::category::ld_share},
-        {"get_ledger", TrafficCount::category::gl_get},
-    };
-    auto it = map.find(name);
-    if (it != map.end())
-        return it->second;
-    return std::nullopt;
-}
-
-std::string
-categoryToName(std::size_t cat)
-{
-    static std::unordered_map<std::size_t, std::string> const map = {
-        {TrafficCount::category::proposal, "proposal"},
-        {TrafficCount::category::validation, "validation"},
-        {TrafficCount::category::transaction, "transaction"},
-        {TrafficCount::category::manifests, "manifests"},
-        {TrafficCount::category::ld_share, "ledger_data"},
-        {TrafficCount::category::gl_get, "get_ledger"},
-    };
-    auto it = map.find(cat);
-    if (it != map.end())
-        return it->second;
-    return std::to_string(cat);
-}
-}  // namespace
-
 Json::Value
 doRuntimeConfig(RPC::JsonContext& context)
 {
@@ -111,24 +74,29 @@ doRuntimeConfig(RPC::JsonContext& context)
             if (v.isMember("message_types"))
             {
                 auto const& mts = v["message_types"];
-                cfg.messageCategories.emplace();  // set to empty = "all"
-                if (mts.isArray())
+                if (!mts.isArray())
                 {
-                    for (auto const& mt : mts)
-                    {
-                        auto const name = mt.asString();
-                        auto cat = categoryFromName(name);
-                        if (!cat)
-                        {
-                            Json::Value err{Json::objectValue};
-                            err["error"] = "invalidParams";
-                            err["error_message"] =
-                                "Unknown message_type: " + name;
-                            return err;
-                        }
-                        cfg.messageCategories->insert(*cat);
-                    }
+                    Json::Value err{Json::objectValue};
+                    err["error"] = "invalidParams";
+                    err["error_message"] = "message_types must be an array";
+                    return err;
                 }
+
+                std::vector<std::string> names;
+                for (auto const& mt : mts)
+                    names.push_back(mt.asString());
+
+                std::string error;
+                auto cats =
+                    runtimeConfigMessageCategoriesFromNames(names, error);
+                if (!cats)
+                {
+                    Json::Value err{Json::objectValue};
+                    err["error"] = "invalidParams";
+                    err["error_message"] = error;
+                    return err;
+                }
+                cfg.messageCategories = *cats;
             }
             rc.setConfig(target, cfg);
         }
@@ -175,7 +143,7 @@ doRuntimeConfig(RPC::JsonContext& context)
         {
             Json::Value types{Json::arrayValue};
             for (auto cat : *cfg.messageCategories)
-                types.append(categoryToName(cat));
+                types.append(runtimeConfigMessageCategoryName(cat));
             entry["message_types"] = types;
         }
         configs[target] = entry;