diff --git a/Cargo.lock b/Cargo.lock
index 610492c1..b580ebff 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -66,7 +66,7 @@ checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
 [[package]]
 name = "codegraph-core"
-version = "3.9.3"
+version = "3.9.4"
 dependencies = [
  "ignore",
  "napi",
@@ -892,9 +892,9 @@ dependencies = [
 
 [[package]]
 name = "tree-sitter-scala"
-version = "0.25.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "83079f50ea7d03e0faf6be6260ed97538e6df7349ec3cbcbf5771f7b38e3c8b7"
+checksum = "3b4f354028b5fcf1d0c77f1c6d84cd5a579f29a1e43cb61551ec6580e9a99229"
 dependencies = [
  "cc",
  "tree-sitter-language",
@@ -902,9 +902,9 @@ dependencies = [
 
 [[package]]
 name = "tree-sitter-swift"
-version = "0.7.1"
+version = "0.6.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4ef216011c3e3df4fa864736f347cb8d509b1066cf0c8549fb1fd81ac9832e59"
+checksum = "d65aeb41726119416567d0333ec17580ac4abfb96db1f67c4bd638c65f9992fe"
 dependencies = [
  "cc",
  "tree-sitter-language",
diff --git a/crates/codegraph-core/Cargo.toml b/crates/codegraph-core/Cargo.toml
index e173e8a5..c7e41cfe 100644
--- a/crates/codegraph-core/Cargo.toml
+++ b/crates/codegraph-core/Cargo.toml
@@ -25,8 +25,8 @@ tree-sitter-php = "0.23"
 tree-sitter-c = "0.23"
 tree-sitter-cpp = "0.23"
 tree-sitter-kotlin-sg = "0.4"
-tree-sitter-swift = "0.7"
-tree-sitter-scala = "0.25"
+tree-sitter-swift = "0.6"
+tree-sitter-scala = "0.24"
 tree-sitter-bash = "0.23"
 tree-sitter-hcl = "1"
 tree-sitter-elixir = "0.3"
diff --git a/crates/codegraph-core/src/config.rs b/crates/codegraph-core/src/config.rs
index af2805bc..d37d54c1 100644
--- a/crates/codegraph-core/src/config.rs
+++ b/crates/codegraph-core/src/config.rs
@@ -23,7 +23,7 @@ pub struct BuildConfig {
     pub aliases: std::collections::HashMap<String, String>,
 }
 
-#[derive(Debug, Clone, Deserialize, Default)]
+#[derive(Debug, Clone, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct BuildSettings {
     /// Whether incremental builds are enabled (default: true).
@@ -35,6 +35,18 @@ pub struct BuildSettings {
     pub drift_threshold: f64,
 }
 
+// Manual impl so `BuildSettings::default()` matches the serde field defaults.
+// `#[derive(Default)]` would give `incremental: false`, which disagrees with
+// `#[serde(default = "default_true")]` when the outer `build` key is absent.
+impl Default for BuildSettings {
+    fn default() -> Self {
+        Self {
+            incremental: default_true(),
+            drift_threshold: default_drift_threshold(),
+        }
+    }
+}
+
 fn default_true() -> bool {
     true
 }