diff --git a/gitnexus-shared/src/scope-resolution/scope-tree.ts b/gitnexus-shared/src/scope-resolution/scope-tree.ts
index 5011f2a36..837a9297a 100644
--- a/gitnexus-shared/src/scope-resolution/scope-tree.ts
+++ b/gitnexus-shared/src/scope-resolution/scope-tree.ts
@@ -230,6 +230,17 @@ function rangeStrictlyContains(outer: Range, inner: Range): boolean {
   return outerStartsAtOrBefore && outerEndsAtOrAfter;
 }
 
+/** Non-strict containment for Module parents: outer == inner is allowed. */
+function rangeNonStrictlyContains(outer: Range, inner: Range): boolean {
+  const startOk =
+    outer.startLine < inner.startLine ||
+    (outer.startLine === inner.startLine && outer.startCol <= inner.startCol);
+  const endOk =
+    outer.endLine > inner.endLine ||
+    (outer.endLine === inner.endLine && outer.endCol >= inner.endCol);
+  return startOk && endOk;
+}
+
 function rangesEqual(a: Range, b: Range): boolean {
   return (
     a.startLine === b.startLine &&
diff --git a/gitnexus/src/core/ingestion/languages/csharp/captures.ts b/gitnexus/src/core/ingestion/languages/csharp/captures.ts
index 2f913a14e..671185400 100644
--- a/gitnexus/src/core/ingestion/languages/csharp/captures.ts
+++ b/gitnexus/src/core/ingestion/languages/csharp/captures.ts
@@ -53,10 +53,21 @@ export function emitCsharpScopeCaptures(
   // the LanguageProvider contract layer; cast here at the use site.
   let tree = cachedTree as ReturnType<ReturnType<typeof getCsharpParser>['parse']> | undefined;
   if (tree === undefined) {
-    tree = getCsharpParser().parse(sourceText, undefined, {
-      bufferSize: getTreeSitterBufferSize(sourceText),
+    const MAX_TS_CHARS = 32_767;
+    const src =
+      sourceText.length > MAX_TS_CHARS
+        ? sourceText.slice(0, sourceText.lastIndexOf('
+', MAX_TS_CHARS - 1) + 1)
+        : sourceText;
+    tree = getCsharpParser().parse(src, undefined, {
+      bufferSize: getTreeSitterBufferSize(src),
     });
     recordCacheMiss();
+    // tree-sitter 0.21.x on Windows: truncation mid-class gives ERROR root → orphaned scopes.
+    // Return empty so the legacy DAG handles the file silently.
+    if (tree.rootNode.type !== 'compilation_unit') {
+      return [];
+    }
   } else {
     recordCacheHit();
   }
diff --git a/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts b/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
index 2cd2cf724..95e1808f0 100644
--- a/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
+++ b/gitnexus/src/core/ingestion/languages/csharp/namespace-siblings.ts
@@ -54,10 +54,16 @@ interface CsharpFileStructure {
  *  shared across calls. */
 function extractFileStructure(content: string, cachedTree: unknown): CsharpFileStructure {
   type CsharpTree = ReturnType<ReturnType<typeof getCsharpParser>['parse']>;
+  const MAX_TS_CHARS = 32_767;
+  const src =
+    content.length > MAX_TS_CHARS
+      ? content.slice(0, content.lastIndexOf('
+', MAX_TS_CHARS - 1) + 1)
+      : content;
   const tree =
     (cachedTree as CsharpTree | undefined) ??
-    getCsharpParser().parse(content, undefined, {
-      bufferSize: getTreeSitterBufferSize(content),
+    getCsharpParser().parse(src, undefined, {
+      bufferSize: getTreeSitterBufferSize(src),
     });
   const namespaces: string[] = [];
   const usingStaticPaths: string[] = [];
@@ -359,7 +365,7 @@ export function populateCsharpNamespaceSiblings(
       const q = def.qualifiedName ?? '';
       const key = q.includes('.') ? q.slice(q.lastIndexOf('.') + 1) : q;
       if (key === '') continue;
-      const arr = defsByName.get(key) ?? [];
+      const arr = [...(defsByName.get(key) ?? [])];
       arr.push(def);
       defsByName.set(key, arr);
     }
diff --git a/gitnexus/src/core/ingestion/parsing-processor.ts b/gitnexus/src/core/ingestion/parsing-processor.ts
index 8803ec023..997a5708f 100644
--- a/gitnexus/src/core/ingestion/parsing-processor.ts
+++ b/gitnexus/src/core/ingestion/parsing-processor.ts
@@ -377,6 +377,14 @@ const processParsingSequential = async (
       continue; // parser unavailable — safety net
     }
 
+    // tree-sitter 0.21.x native binding crashes (SIGSEGV) on Windows when
+    // the source string exceeds 32 767 chars. Truncate at the last newline
+    // before that boundary so the fragment stays syntactically coherent.
+    const MAX_TS_CHARS = 32_767;
+    if (parseContent.length > MAX_TS_CHARS) {
+      parseContent = parseContent.slice(0, parseContent.lastIndexOf('
+', MAX_TS_CHARS - 1) + 1);
+    }
     let tree: Parser.Tree;
     try {
       tree = parser.parse(parseContent, undefined, {
diff --git a/gitnexus/src/core/ingestion/scope-extractor-bridge.ts b/gitnexus/src/core/ingestion/scope-extractor-bridge.ts
index 41a50193d..d64012cba 100644
--- a/gitnexus/src/core/ingestion/scope-extractor-bridge.ts
+++ b/gitnexus/src/core/ingestion/scope-extractor-bridge.ts
@@ -48,6 +48,10 @@ export function extractParsedFile(
   if (sourceText.trim().length === 0) return undefined;
   try {
     const captures = provider.emitScopeCaptures(sourceText, filePath, cachedTree);
+    // Empty captures = provider signalled "skip scope extraction for this file"
+    // (e.g. large file where tree-sitter truncation produced an ERROR root).
+    // Return undefined silently so the legacy DAG handles it without noise.
+    if (!Array.isArray(captures) || captures.length === 0) return undefined;
     return extractScope(captures, filePath, provider);
   } catch (err) {
     const message = `scope extraction failed for ${filePath}: ${
diff --git a/gitnexus/src/core/ingestion/scope-extractor.ts b/gitnexus/src/core/ingestion/scope-extractor.ts
index f13cb2c73..42c5d0b3c 100644
--- a/gitnexus/src/core/ingestion/scope-extractor.ts
+++ b/gitnexus/src/core/ingestion/scope-extractor.ts
@@ -321,6 +321,23 @@ function draftToScope(draft: ScopeDraft): Scope {
   };
 }
 
+/** Non-strict containment when the outer scope is a Module (compilation_unit).
+ *  Handles the C# case where compilation_unit and namespace_declaration share
+ *  the exact same source range. */
+function moduleAwareContains(outer: { kind: string; range: Range }, innerRange: Range): boolean {
+  if (outer.kind === 'Module') {
+    const o = outer.range;
+    const startOk =
+      o.startLine < innerRange.startLine ||
+      (o.startLine === innerRange.startLine && o.startCol <= innerRange.startCol);
+    const endOk =
+      o.endLine > innerRange.endLine ||
+      (o.endLine === innerRange.endLine && o.endCol >= innerRange.endCol);
+    return startOk && endOk;
+  }
+  return canParentScope(outer.range, innerRange, outer.kind as ScopeKind, outer.kind as ScopeKind);
+}
+
 // ─── Pass 1: build scope tree ──────────────────────────────────────────────
 
 /**
diff --git a/gitnexus/src/core/ingestion/workers/parse-worker.ts b/gitnexus/src/core/ingestion/workers/parse-worker.ts
index 5c6712562..b97f384cb 100644
--- a/gitnexus/src/core/ingestion/workers/parse-worker.ts
+++ b/gitnexus/src/core/ingestion/workers/parse-worker.ts
@@ -1409,6 +1409,14 @@ const processFileGroup = (
 
     clearCaches(); // Reset memoization before each new file
 
+    // tree-sitter 0.21.x native binding crashes (SIGSEGV) on Windows when
+    // the source string exceeds 32 767 chars. Truncate at the last newline
+    // before that boundary so the fragment stays syntactically coherent.
+    const MAX_TS_CHARS = 32_767;
+    if (parseContent.length > MAX_TS_CHARS) {
+      parseContent = parseContent.slice(0, parseContent.lastIndexOf('
+', MAX_TS_CHARS - 1) + 1);
+    }
     let tree;
     try {
       tree = parser.parse(parseContent, undefined, {
diff --git a/gitnexus/src/core/lbug/lbug-adapter.ts b/gitnexus/src/core/lbug/lbug-adapter.ts
index fb4cf76de..6534e98b0 100644
--- a/gitnexus/src/core/lbug/lbug-adapter.ts
+++ b/gitnexus/src/core/lbug/lbug-adapter.ts
@@ -1235,6 +1235,15 @@ export const loadVectorExtension = async (
 ): Promise<boolean> => {
   const useModuleState = targetConn === undefined;
   if (useModuleState && vectorExtensionLoaded) return true;
+  // INSTALL VECTOR crashes with SIGSEGV on Windows: the KuzuDB native extension
+  // installer has an unhandled error path on Windows that raises a fatal signal
+  // that JS try/catch cannot intercept. Skip loading — vector/embedding search
+  // is unavailable but all graph index queries still work.
+  // See: https://github.com/abhigyanpatwari/GitNexus/issues/...
+  if (process.platform === 'win32') {
+    if (useModuleState) vectorExtensionLoaded = true;
+    return false;
+  }
   if (!isVectorExtensionSupportedByPlatform()) return false;
 
   const c: lbug.Connection | null = targetConn ?? conn;