diff --git a/gitnexus/src/core/ingestion/languages/c/header-scan.ts b/gitnexus/src/core/ingestion/languages/c/header-scan.ts
index f74d3fa89..033bfd9eb 100644
--- a/gitnexus/src/core/ingestion/languages/c/header-scan.ts
+++ b/gitnexus/src/core/ingestion/languages/c/header-scan.ts
@@ -27,8 +27,21 @@ function walk(dir: string, root: string, out: Set<string>): void {
     const name = entry.name;
     const full = join(dir, name);
     if (entry.isDirectory()) {
-      // Skip common non-source directories
-      if (name === 'node_modules' || name === '.git' || name === 'vendor') {
+      // Skip common non-source directories and build output dirs.
+      // Build dirs (dist, build, out, target, _build, .next, cmake-build-*)
+      // may contain generated headers that shadow source headers.
+      if (
+        name === 'node_modules' ||
+        name === '.git' ||
+        name === 'vendor' ||
+        name === 'dist' ||
+        name === 'build' ||
+        name === 'out' ||
+        name === 'target' ||
+        name === '_build' ||
+        name === '.next' ||
+        name.startsWith('cmake-build')
+      ) {
         continue;
       }
       walk(full, root, out);
diff --git a/gitnexus/src/core/ingestion/languages/c/import-target.ts b/gitnexus/src/core/ingestion/languages/c/import-target.ts
index a90da6216..4af025334 100644
--- a/gitnexus/src/core/ingestion/languages/c/import-target.ts
+++ b/gitnexus/src/core/ingestion/languages/c/import-target.ts
@@ -1,26 +1,41 @@
+import { dirname, join } from 'path';
+
 /**
  * Resolve a C #include path to a file in the workspace.
  *
- * Strategy: match the include path suffix against all file paths in
- * the workspace. "foo.h" matches "src/foo.h", "include/foo.h", etc.
- * For paths with directory components ("dir/foo.h"), match the full
- * relative suffix.
- *
- * Tie-breaking: prefer the match with the fewest path components
- * (closest to root). On equal depth, break ties lexicographically
- * by normalized path to ensure deterministic resolution regardless
- * of filesystem iteration order.
+ * Strategy:
+ * 1. Check for a same-directory sibling relative to the including file
+ *    (matches C compiler `#include "…"` relative-lookup semantics).
+ * 2. Check for an exact match (path as-is in the workspace).
+ * 3. Fall back to suffix matching against all workspace file paths.
+ *    Tie-breaking: prefer the match with the fewest path components
+ *    (closest to root). On equal depth, break ties lexicographically
+ *    by normalized path to ensure deterministic resolution regardless
+ *    of filesystem iteration order.
  */
 export function resolveCImportTarget(
   targetRaw: string,
-  _fromFile: string,
+  fromFile: string,
   allFilePaths: ReadonlySet<string>,
 ): string | null {
   if (!targetRaw) return null;
 
   const normalizedTarget = targetRaw.replace(/\\/g, '/');
 
-  // Exact match first
+  // Same-directory sibling first: mirrors the C compiler's #include "…"
+  // relative-lookup semantics where the directory of the including
+  // file is searched before the include-path list.
+  if (fromFile) {
+    const siblingRaw = join(dirname(fromFile), targetRaw);
+    const sibling = siblingRaw.replace(/\\/g, '/');
+    if (allFilePaths.has(sibling)) return sibling;
+    // Also try normalized target in case targetRaw has slashes
+    const siblingAlt = join(dirname(fromFile), normalizedTarget);
+    const siblingAltNorm = siblingAlt.replace(/\\/g, '/');
+    if (siblingAltNorm !== sibling && allFilePaths.has(siblingAltNorm)) return siblingAltNorm;
+  }
+
+  // Exact match (path as-is in the workspace)
   if (allFilePaths.has(normalizedTarget)) return normalizedTarget;
 
   // Suffix match: find files ending with /targetRaw or equal to targetRaw
diff --git a/gitnexus/src/core/ingestion/scope-resolution/passes/free-call-fallback.ts b/gitnexus/src/core/ingestion/scope-resolution/passes/free-call-fallback.ts
index d63c3906a..44f941daf 100644
--- a/gitnexus/src/core/ingestion/scope-resolution/passes/free-call-fallback.ts
+++ b/gitnexus/src/core/ingestion/scope-resolution/passes/free-call-fallback.ts
@@ -141,6 +141,12 @@ function pickUniqueGlobalCallable(
   const seen = new Set<string>();
   const push = (pool: readonly SymbolDefinition[]): void => {
     for (const def of pool) {
+      // Apply the same file-local linkage filter as Phase 1 —
+      // cross-file static defs must never leak through the
+      // SemanticModel fallback path.
+      if (isFileLocalDef !== undefined && def.filePath !== callerFilePath && isFileLocalDef(def)) {
+        continue;
+      }
       const key = logicalCallableKey(def);
       if (seen.has(key)) continue;
       seen.add(key);
diff --git a/gitnexus/test/unit/scope-resolution/c/c-header-scan.test.ts b/gitnexus/test/unit/scope-resolution/c/c-header-scan.test.ts
new file mode 100644
index 000000000..1543db006
--- /dev/null
+++ b/gitnexus/test/unit/scope-resolution/c/c-header-scan.test.ts
@@ -0,0 +1,103 @@
+/**
+ * Unit tests for C header scanning — specifically the skip-list
+ * for build output directories.
+ */
+
+import { describe, it, expect, beforeEach, afterEach } from 'vitest';
+import { mkdirSync, writeFileSync, rmSync } from 'fs';
+import { join } from 'path';
+import { scanHeaderFiles } from '../../../../src/core/ingestion/languages/c/header-scan.js';
+
+const TMP = join(__dirname, '__header_scan_tmp__');
+
+function touch(rel: string): void {
+  const full = join(TMP, rel);
+  mkdirSync(join(full, '..'), { recursive: true });
+  writeFileSync(full, '');
+}
+
+beforeEach(() => {
+  mkdirSync(TMP, { recursive: true });
+});
+
+afterEach(() => {
+  rmSync(TMP, { recursive: true, force: true });
+});
+
+describe('scanHeaderFiles — build-directory skip list', () => {
+  it('finds .h files in source directories', () => {
+    touch('src/foo.h');
+    touch('include/bar.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers).toContain('src/foo.h');
+    expect(headers).toContain('include/bar.h');
+  });
+
+  it('skips node_modules', () => {
+    touch('node_modules/dep/header.h');
+    touch('src/real.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers).not.toContain('node_modules/dep/header.h');
+    expect(headers).toContain('src/real.h');
+  });
+
+  it('skips .git directory', () => {
+    touch('.git/refs/header.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips vendor directory', () => {
+    touch('vendor/lib/header.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips dist directory', () => {
+    touch('dist/generated.h');
+    touch('src/real.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers).not.toContain('dist/generated.h');
+    expect(headers).toContain('src/real.h');
+  });
+
+  it('skips build directory', () => {
+    touch('build/config.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers).not.toContain('build/config.h');
+  });
+
+  it('skips out directory', () => {
+    touch('out/gen/auto.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips target directory', () => {
+    touch('target/release/bindings.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips _build directory', () => {
+    touch('_build/default/lib.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips .next directory', () => {
+    touch('.next/cache/header.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers.size).toBe(0);
+  });
+
+  it('skips cmake-build-* directories', () => {
+    touch('cmake-build-debug/generated.h');
+    touch('cmake-build-release/generated.h');
+    touch('src/real.h');
+    const headers = scanHeaderFiles(TMP);
+    expect(headers).not.toContain('cmake-build-debug/generated.h');
+    expect(headers).not.toContain('cmake-build-release/generated.h');
+    expect(headers).toContain('src/real.h');
+  });
+});
diff --git a/gitnexus/test/unit/scope-resolution/c/c-imports.test.ts b/gitnexus/test/unit/scope-resolution/c/c-imports.test.ts
index 274274ef4..7496502f6 100644
--- a/gitnexus/test/unit/scope-resolution/c/c-imports.test.ts
+++ b/gitnexus/test/unit/scope-resolution/c/c-imports.test.ts
@@ -128,4 +128,43 @@ describe('C import target resolution (resolveCImportTarget)', () => {
     const result = resolveCImportTarget('foo.h', 'main.c', new Set(['include\\foo.h']));
     expect(result).toBe('include\\foo.h');
   });
+
+  it('prefers same-directory sibling over deeper suffix match', () => {
+    // src/foo.c includes "bar.h" — src/bar.h should win over include/bar.h
+    const result = resolveCImportTarget(
+      'bar.h',
+      'src/foo.c',
+      new Set(['include/bar.h', 'src/bar.h']),
+    );
+    expect(result).toBe('src/bar.h');
+  });
+
+  it('prefers same-directory sibling over shallower suffix match', () => {
+    // deep/nested/main.c includes "foo.h" — deep/nested/foo.h wins over foo.h
+    const result = resolveCImportTarget(
+      'foo.h',
+      'deep/nested/main.c',
+      new Set(['foo.h', 'deep/nested/foo.h']),
+    );
+    expect(result).toBe('deep/nested/foo.h');
+  });
+
+  it('falls back to suffix match when no same-directory sibling exists', () => {
+    const result = resolveCImportTarget(
+      'missing.h',
+      'src/foo.c',
+      new Set(['lib/missing.h']),
+    );
+    expect(result).toBe('lib/missing.h');
+  });
+
+  it('same-directory sibling with nested target path', () => {
+    // src/foo.c includes "sub/bar.h" — src/sub/bar.h should win
+    const result = resolveCImportTarget(
+      'sub/bar.h',
+      'src/foo.c',
+      new Set(['other/sub/bar.h', 'src/sub/bar.h']),
+    );
+    expect(result).toBe('src/sub/bar.h');
+  });
 });