diff --git a/res/content/base/generators/demo.files/biomes.json b/res/content/base/generators/demo.files/biomes.json
deleted file mode 100644
index 52bb9598..00000000
--- a/res/content/base/generators/demo.files/biomes.json
+++ /dev/null
@@ -1,68 +0,0 @@
-{
-    "forest": {
-        "parameters": [
-            {"weight": 1, "value": 1},
-            {"weight": 0.5, "value": 0.2}
-        ],
-        "layers": [
-            {"below_sea_level": false, "height": 1, "block": "base:grass_block"},
-            {"below_sea_level": false, "height": 7, "block": "base:dirt"},
-            {"height": -1, "block": "base:stone"},
-            {"height": 1, "block": "base:bazalt"}
-        ],
-        "sea_layers": [
-            {"height": -1, "block": "base:water"}
-        ],
-        "plant_chance": 0.4,
-        "plants": [
-            {"weight": 1, "block": "base:grass"},
-            {"weight": 0.03, "block": "base:flower"}
-        ],
-        "structure_chance": 0.032,
-        "structures": [
-            {"name": "tree0", "weight": 1},
-            {"name": "tree1", "weight": 1},
-            {"name": "tree2", "weight": 1},
-            {"name": "tower", "weight": 0.002}
-        ]
-    },
-    "desert": {
-        "parameters": [
-            {"weight": 0.3, "value": 0},
-            {"weight": 0.1, "value": 0}
-        ],
-        "layers": [
-            {"height": 6, "block": "base:sand"},
-            {"height": -1, "block": "base:stone"},
-            {"height": 1, "block": "base:bazalt"}
-        ],
-        "sea_layers": [
-            {"height": -1, "block": "base:water"}
-        ]
-    },
-    "plains": {
-        "parameters": [
-            {"weight": 0.6, "value": 0.5},
-            {"weight": 0.6, "value": 0.5}
-        ],
-        "layers": [
-            {"below_sea_level": false, "height": 1, "block": "base:grass_block"},
-            {"below_sea_level": false, "height": 5, "block": "base:dirt"},
-            {"height": -1, "block": "base:stone"},
-            {"height": 1, "block": "base:bazalt"}
-        ],
-        "sea_layers": [
-            {"height": -1, "block": "base:water"}
-        ],
-        "plant_chance": 0.3,
-        "plants": [
-            {"weight": 1, "block": "base:grass"},
-            {"weight": 0.03, "block": "base:flower"}
-        ],
-        "structure_chance": 0.0001,
-        "structures": [
-            {"name": "tree0", "weight": 1},
-            {"name": "tree1", "weight": 1}
-        ]
-    }
-}
diff --git a/res/content/base/generators/demo.files/biomes.toml b/res/content/base/generators/demo.files/biomes.toml
new file mode 100644
index 00000000..d782d991
--- /dev/null
+++ b/res/content/base/generators/demo.files/biomes.toml
@@ -0,0 +1,67 @@
+[forest]
+parameters = [
+    {weight=1, value=1},
+    {weight=0.5, value=0.2}
+]
+layers = [
+    {below_sea_level=false, height=1, block="base:grass_block"},
+    {below_sea_level=false, height=7, block="base:dirt"},
+    {height=-1, block="base:stone"},
+    {height=1, block="base:bazalt"}
+]
+sea_layers = [
+    {height=-1, block="base:water"}
+]
+plant_chance = 0.4
+plants = [
+    {weight=1, block="base:grass"},
+    {weight=0.03, block="base:flower"}
+]
+structure_chance = 0.032
+structures = [
+    {name="tree0", weight=1},
+    {name="tree1", weight=1},
+    {name="tree2", weight=1},
+    {name="tower", weight=0.002}
+]
+
+
+[desert]
+parameters = [
+    {weight=0.3, value=0},
+    {weight=0.1, value=0}
+]
+layers = [
+    {height=6, block="base:sand"},
+    {height=-1, block="base:stone"},
+    {height=1, block="base:bazalt"}
+]
+sea_layers = [
+    {height=-1, block="base:water"}
+]
+
+
+[plains]
+parameters = [
+    {weight=0.6, value=0.5},
+    {weight=0.6, value=0.5}
+]
+layers = [
+    {below_sea_level=false, height=1, block="base:grass_block"},
+    {below_sea_level=false, height=5, block="base:dirt"},
+    {height=-1, block="base:stone"},
+    {height=1, block="base:bazalt"}
+]
+sea_layers = [
+    {height=-1, block="base:water"}
+]
+plant_chance = 0.3
+plants = [
+    {weight=1, block="base:grass"},
+    {weight=0.03, block="base:flower"}
+]
+structure_chance=0.0001
+structures = [
+    {name="tree0", weight=1},
+    {name="tree1", weight=1}
+]
diff --git a/res/generators/default.files/biomes.json b/res/generators/default.files/biomes.json
deleted file mode 100644
index baf0bf9b..00000000
--- a/res/generators/default.files/biomes.json
+++ /dev/null
@@ -1,11 +0,0 @@
-{
-    "flat": {
-        "parameters": [],
-        "layers": [
-            {"height": -1, "block": "core:obstacle"}
-        ],
-        "sea_layers": [
-            {"height": -1, "block": "core:obstacle"}
-        ]
-    }
-}
diff --git a/res/generators/default.files/biomes.toml b/res/generators/default.files/biomes.toml
new file mode 100644
index 00000000..94d6e7cd
--- /dev/null
+++ b/res/generators/default.files/biomes.toml
@@ -0,0 +1,8 @@
+[flat]
+parameters = []
+layers = [
+    {height=-1, block="core:obstacle"}
+]
+sea_layers = [
+    {height=-1, block="core:obstacle"}
+]
diff --git a/src/coders/json.cpp b/src/coders/json.cpp
index 9c189998..05db4e13 100644
--- a/src/coders/json.cpp
+++ b/src/coders/json.cpp
@@ -242,7 +242,7 @@ dv::value Parser::parseValue() {
         } else if (literal == "nan") {
             return NAN;
         }
-        throw error("invalid literal ");
+        throw error("invalid keyword " + literal);
     }
     if (next == '{') {
         return parseObject();
diff --git a/src/content/ContentLoader.cpp b/src/content/ContentLoader.cpp
index 151ed19f..bc03b810 100644
--- a/src/content/ContentLoader.cpp
+++ b/src/content/ContentLoader.cpp
@@ -28,8 +28,10 @@ using namespace data;
 
 static debug::Logger logger("content-loader");
 
-ContentLoader::ContentLoader(ContentPack* pack, ContentBuilder& builder)
-    : pack(pack), builder(builder) {
+ContentLoader::ContentLoader(
+    ContentPack* pack, ContentBuilder& builder, const ResPaths& paths
+)
+    : pack(pack), builder(builder), paths(paths) {
     auto runtime = std::make_unique<ContentPackRuntime>(
         *pack, scripting::create_pack_environment(*pack)
     );
diff --git a/src/content/ContentLoader.hpp b/src/content/ContentLoader.hpp
index 762b3fbe..efd54efd 100644
--- a/src/content/ContentLoader.hpp
+++ b/src/content/ContentLoader.hpp
@@ -16,6 +16,7 @@ struct EntityDef;
 struct ContentPack;
 struct GeneratorDef;
 
+class ResPaths;
 class ContentBuilder;
 class ContentPackRuntime;
 struct ContentPackStats;
@@ -26,6 +27,7 @@ class ContentLoader {
     scriptenv env;
     ContentBuilder& builder;
     ContentPackStats* stats;
+    const ResPaths& paths;
 
     void loadBlock(
         Block& def, const std::string& full, const std::string& name
@@ -55,7 +57,11 @@ class ContentLoader {
 
     void loadContent(const dv::value& map);
 public:
-    ContentLoader(ContentPack* pack, ContentBuilder& builder);
+    ContentLoader(
+        ContentPack* pack,
+        ContentBuilder& builder,
+        const ResPaths& paths
+    );
 
     // Refresh pack content.json
     static bool fixPackIndices(
diff --git a/src/content/loading/GeneratorLoader.cpp b/src/content/loading/GeneratorLoader.cpp
index eef4fb1c..72cd330c 100644
--- a/src/content/loading/GeneratorLoader.cpp
+++ b/src/content/loading/GeneratorLoader.cpp
@@ -3,10 +3,12 @@
 #include "../ContentPack.hpp"
 
 #include "files/files.hpp"
+#include "files/engine_paths.hpp"
 #include "logic/scripting/scripting.hpp"
 #include "world/generator/GeneratorDef.hpp"
 #include "world/generator/VoxelFragment.hpp"
 #include "debug/Logger.hpp"
+#include "util/stringutil.hpp"
 
 static BlocksLayer load_layer(
     const dv::value& map, uint& lastLayersHeight, bool& hasResizeableLayer
@@ -167,11 +169,10 @@ static void load_structures(GeneratorDef& def, const fs::path& structuresFile) {
 }
 
 static inline const auto STRUCTURES_FILE = fs::u8path("structures.json");
-static inline const auto BIOMES_FILE = fs::u8path("biomes.json");
+static inline const auto BIOMES_FILE = fs::u8path("biomes.toml");
 static inline const auto GENERATORS_DIR = fs::u8path("generators");
 
-static void load_biomes(GeneratorDef& def, const fs::path& file) {
-    auto root = files::read_json(file);
+static void load_biomes(GeneratorDef& def, const dv::value& root) {
     for (const auto& [biomeName, biomeMap] : root.asObject()) {
         try {
             def.biomes.push_back(
@@ -205,14 +206,16 @@ void ContentLoader::loadGenerator(
     if (fs::exists(structuresFile)) {
         load_structures(def, structuresFile);
     }
-    auto biomesFiles = folder / BIOMES_FILE;
-    if (!fs::exists(biomesFiles)) {
+
+    auto biomesFile = GENERATORS_DIR / fs::u8path(name + ".files") / BIOMES_FILE;
+    auto biomesMap = paths.readCombinedObject(biomesFile.u8string());
+    if (biomesMap.empty()) {
         throw std::runtime_error(
-            BIOMES_FILE.u8string() +
-            ": file not found (at least one biome required)"
+            "generator " + util::quote(def.name) +
+            ": at least one biome required"
         );
     }
-    load_biomes(def, biomesFiles);
+    load_biomes(def, biomesMap);
     def.script = scripting::load_generator(
         def, scriptFile, pack->id+":generators/"+name+".files");
 }
diff --git a/src/engine.cpp b/src/engine.cpp
index a7b94bbb..b32128f7 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -322,11 +322,11 @@ void Engine::loadContent() {
 
     // Load content
     {
-        ContentLoader(&corePack, contentBuilder).load();
+        ContentLoader(&corePack, contentBuilder, *resPaths).load();
         load_configs(corePack.folder);
     }
     for (auto& pack : contentPacks) {
-        ContentLoader(&pack, contentBuilder).load();
+        ContentLoader(&pack, contentBuilder, *resPaths).load();
         load_configs(pack.folder);
     } 
 
diff --git a/src/files/engine_paths.cpp b/src/files/engine_paths.cpp
index c826457f..6bc42cc1 100644
--- a/src/files/engine_paths.cpp
+++ b/src/files/engine_paths.cpp
@@ -255,7 +255,7 @@ std::vector<std::filesystem::path> ResPaths::listdir(
     return entries;
 }
 
-dv::value ResPaths::readCombinedList(const std::string& filename) {
+dv::value ResPaths::readCombinedList(const std::string& filename) const {
     dv::value list = dv::list();
     for (const auto& root : roots) {
         auto path = root.path / fs::u8path(filename);
@@ -280,6 +280,31 @@ dv::value ResPaths::readCombinedList(const std::string& filename) {
     return list;
 }
 
+dv::value ResPaths::readCombinedObject(const std::string& filename) const {
+    dv::value object = dv::object();
+    for (const auto& root : roots) {
+        auto path = root.path / fs::u8path(filename);
+        if (!fs::exists(path)) {
+            continue;
+        }
+        try {
+            auto value = files::read_object(path);
+            if (!value.isObject()) {
+                logger.warning()
+                    << "reading combined object " << root.name << ": "
+                    << filename << " is not an object (skipped)";
+            }
+            for (const auto& [key, element] : value.asObject())  {
+                object[key] = element;
+            }
+        } catch (const std::runtime_error& err) {
+            logger.warning() << "reading combined object " << root.name << ":"
+                             << filename << ": " << err.what();
+        }
+    }
+    return object;
+}
+
 const std::filesystem::path& ResPaths::getMainRoot() const {
     return mainRoot;
 }
diff --git a/src/files/engine_paths.hpp b/src/files/engine_paths.hpp
index ec0c38d5..3abcb4ea 100644
--- a/src/files/engine_paths.hpp
+++ b/src/files/engine_paths.hpp
@@ -68,7 +68,9 @@ public:
     /// @brief Read all found list versions from all packs and combine into a
     /// single list. Invalid versions will be skipped with logging a warning
     /// @param file *.json file path relative to entry point 
-    dv::value readCombinedList(const std::string& file);
+    dv::value readCombinedList(const std::string& file) const;
+
+    dv::value readCombinedObject(const std::string& file) const;
 
     const std::filesystem::path& getMainRoot() const;
 
diff --git a/src/world/generator/WorldGenerator.cpp b/src/world/generator/WorldGenerator.cpp
index db3d157d..14c0c5aa 100644
--- a/src/world/generator/WorldGenerator.cpp
+++ b/src/world/generator/WorldGenerator.cpp
@@ -251,6 +251,7 @@ void WorldGenerator::generateStructures(
     util::PseudoRandom structsRand;
     structsRand.setSeed(chunkX, chunkZ);
 
+    // Place structures defined in biome
     auto heights = heightmap->getValues();
     for (uint z = 0; z < CHUNK_D; z++) {
         for (uint x = 0; x < CHUNK_W; x++) {