diff --git a/src/config.cpp b/src/config.cpp
index 94c908a..c6492ee 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -301,7 +301,37 @@ CParseResult CConfig::configSetValueSafe(const std::string& command, const std::
 
     const auto VALUEONLYNAME = command.starts_with(catPrefix) ? command.substr(catPrefix.length()) : command;
 
-    auto       VALUEIT = impl->values.find(valueName);
+    // FIXME: this will bug with nested.
+    if (valueName.contains('[') && valueName.contains(']')) {
+        const auto L = valueName.find_first_of('[');
+        const auto R = valueName.find_last_of(']');
+
+        if (L < R) {
+            const auto CATKEY       = valueName.substr(L + 1, R - L - 1);
+            impl->currentSpecialKey = CATKEY;
+
+            valueName = valueName.substr(0, L) + valueName.substr(R + 1);
+
+            // if it doesn't exist, make it
+            for (auto& sc : impl->specialCategoryDescriptors) {
+                if (sc->key.empty() || !valueName.starts_with(sc->name))
+                    continue;
+
+                // bingo
+                const auto PCAT  = impl->specialCategories.emplace_back(std::make_unique<SSpecialCategory>()).get();
+                PCAT->descriptor = sc.get();
+                PCAT->name       = sc->name;
+                PCAT->key        = sc->key;
+                addSpecialConfigValue(sc->name.c_str(), sc->key.c_str(), CConfigValue(CATKEY.c_str()));
+
+                applyDefaultsToCat(*PCAT);
+
+                PCAT->values[sc->key].setFrom(CATKEY);
+            }
+        }
+    }
+
+    auto VALUEIT = impl->values.find(valueName);
     if (VALUEIT == impl->values.end()) {
         // it might be in a special category
         bool found = false;
diff --git a/tests/config/config.conf b/tests/config/config.conf
index f08b8b7..f3b018f 100644
--- a/tests/config/config.conf
+++ b/tests/config/config.conf
@@ -40,8 +40,7 @@ special {
     value = $SPECIALVAL1
 }
 
-special {
-    key = b
+special[b] {
     value = 2
 }
 
diff --git a/tests/parse/main.cpp b/tests/parse/main.cpp
index ae2c4f8..359757a 100644
--- a/tests/parse/main.cpp
+++ b/tests/parse/main.cpp
@@ -199,6 +199,8 @@ int main(int argc, char** argv, char** envp) {
         EXPECT(std::any_cast<int64_t>(config.getSpecialConfigValue("special", "value", "b")), 2);
         EXPECT(std::any_cast<int64_t>(config.getSpecialConfigValue("specialGeneric:one", "value")), 1);
         EXPECT(std::any_cast<int64_t>(config.getSpecialConfigValue("specialGeneric:two", "value")), 2);
+        EXPECT(config.parseDynamic("special[b]:value = 3").error, false);
+        EXPECT(std::any_cast<int64_t>(config.getSpecialConfigValue("special", "value", "b")), 3);
 
         // test dynamic special variable
         EXPECT(config.parseDynamic("$SPECIALVAL1 = 2").error, false);