diff --git a/core/src/main/java/io/github/dfa1/vortex/fbsrt/FbsBuilder.java b/core/src/main/java/io/github/dfa1/vortex/fbsrt/FbsBuilder.java
index 8e53de8e..eb15e704 100644
--- a/core/src/main/java/io/github/dfa1/vortex/fbsrt/FbsBuilder.java
+++ b/core/src/main/java/io/github/dfa1/vortex/fbsrt/FbsBuilder.java
@@ -328,7 +328,7 @@ public int endTable() {
                 continue;
             }
             for (int k = SIZEOF_SHORT; k < len; k += SIZEOF_SHORT) {
-                if (buf.get(LE_SHORT, vt1 + k) != buf.get(LE_SHORT, vt2 + k)) {
+                if (buf.get(LE_SHORT, (long) vt1 + k) != buf.get(LE_SHORT, (long) vt2 + k)) {
                     continue outer;
                 }
             }
@@ -344,7 +344,7 @@ public int endTable() {
                 vtables = Arrays.copyOf(vtables, numVtables * 2);
             }
             vtables[numVtables++] = offset();
-            buf.set(LE_INT, cap - vtableloc, offset() - vtableloc);
+            buf.set(LE_INT, (long) cap - vtableloc, offset() - vtableloc);
         }
         return vtableloc;
     }
diff --git a/fbs-gen/src/main/java/io/github/dfa1/vortex/fbsgen/TypeRegistry.java b/fbs-gen/src/main/java/io/github/dfa1/vortex/fbsgen/TypeRegistry.java
index d4a00ba5..c9b8cc22 100644
--- a/fbs-gen/src/main/java/io/github/dfa1/vortex/fbsgen/TypeRegistry.java
+++ b/fbs-gen/src/main/java/io/github/dfa1/vortex/fbsgen/TypeRegistry.java
@@ -116,6 +116,7 @@ private static int align(int pos, int size) {
     /// @param fieldOffsets byte offset of each field, parallel to the struct's field list
     /// @param size         total padded struct size in bytes
     /// @param alignment    struct alignment (the maximum field alignment)
+    @SuppressWarnings("java:S6218") // codegen-internal data carrier; fieldOffsets is an array of immutable primitives consumed by the generator and never compared.
     public record StructLayout(int[] fieldOffsets, int size, int alignment) {
     }
 }
diff --git a/inspector/src/main/java/io/github/dfa1/vortex/inspect/InspectorTree.java b/inspector/src/main/java/io/github/dfa1/vortex/inspect/InspectorTree.java
index b3705968..3c9bb5ea 100644
--- a/inspector/src/main/java/io/github/dfa1/vortex/inspect/InspectorTree.java
+++ b/inspector/src/main/java/io/github/dfa1/vortex/inspect/InspectorTree.java
@@ -255,8 +255,8 @@ public interface Progress {
 
     private static Peek peekFlatRoot(MemorySegment seg, List<String> arraySpecs) {
         int segLen = (int) seg.byteSize();
-        int fbLen = seg.get(LE_INT, segLen - 4);
-        int fbStart = segLen - 4 - fbLen;
+        int fbLen = seg.get(LE_INT, segLen - 4L);
+        long fbStart = segLen - 4L - fbLen;
         FbsArray fbArray = FbsArray.getRootAsFbsArray(seg.asSlice(fbStart, fbLen));
         FbsArrayNode root = fbArray.root();
         if (root == null) {
diff --git a/pom.xml b/pom.xml
index 6f293230..0dab7776 100644
--- a/pom.xml
+++ b/pom.xml
@@ -95,6 +95,15 @@
 			**/fbs/**,
 			**/proto/**
 		</sonar.exclusions>
+		<!-- The two in-house code generators (fbs-gen, proto-gen) are build-only developer
+		     tooling, not shipped runtime. Their lexers/parsers share the same tokenizer
+		     shape by design (scan char, classify token, advance), which the duplication
+		     metric counts as cross-module copy-paste. Exclude from CPD only — smell and
+		     bug analysis on this hand-written code is kept. -->
+		<sonar.cpd.exclusions>
+			**/fbsgen/**,
+			**/protogen/**
+		</sonar.cpd.exclusions>
 		<!-- Coverage sources:
 		     1. per-module surefire (unit tests)
 		     2. per-module failsafe (module-local integration tests)
diff --git a/reader/src/main/java/io/github/dfa1/vortex/reader/FlatSegmentDecoder.java b/reader/src/main/java/io/github/dfa1/vortex/reader/FlatSegmentDecoder.java
index e5b2cabc..fbdabd8d 100644
--- a/reader/src/main/java/io/github/dfa1/vortex/reader/FlatSegmentDecoder.java
+++ b/reader/src/main/java/io/github/dfa1/vortex/reader/FlatSegmentDecoder.java
@@ -49,7 +49,7 @@ public Array decode(MemorySegment seg, List<String> encodingSpecs,
 
         // The trailing u32 length field must itself be in range before we read it.
         IoBounds.checkRange(segLen - 4L, 4, segLen);
-        int fbLen = seg.get(LE_INT, segLen - 4);
+        int fbLen = seg.get(LE_INT, segLen - 4L);
         long fbStart = segLen - 4L - fbLen;
         IoBounds.checkRange(fbStart, fbLen, segLen);
         var fbArray = io.github.dfa1.vortex.fbs.FbsArray.getRootAsFbsArray(seg.asSlice(fbStart, fbLen));