@@ -28,15 +28,15 @@ export function readHistory(repo: string, baseRef: string, headRef = 'HEAD', lim
     if (diffBytes > maxDiffBytes) throw new Error('Review history exceeds the cumulative diff byte budget; choose a narrower base.');
     return data;
   };
-  // Inherited Git variables can redirect repository, index, config, and object lookup.
-  const environment = Object.fromEntries(Object.entries(process.env).filter(([key]) => !/^GIT_/i.test(key)));
   const run = (...args: string[]) => {
     const timeout = remaining();
     let result: Buffer;
     try {
       result = execFileSync('git', ['--no-pager', '--no-replace-objects', '-c', 'core.hooksPath=/dev/null', '-c', 'protocol.allow=never', ...args], {
         cwd: repo, maxBuffer: 32 * 1024 * 1024, timeout, killSignal: 'SIGKILL',
-        env: { ...environment, GIT_OPTIONAL_LOCKS: '0', GIT_TERMINAL_PROMPT: '0',
+        // Allowlisted: inherited variables can redirect repository, index, config and object lookup, and Git reads
+        // variables outside the GIT_ namespace too, such as HOME and XDG_CONFIG_HOME for user attributes.
+        env: { PATH: process.env.PATH ?? '', GIT_OPTIONAL_LOCKS: '0', GIT_TERMINAL_PROMPT: '0',
           GIT_NO_LAZY_FETCH: '1', GIT_CONFIG_NOSYSTEM: '1', GIT_CONFIG_GLOBAL: '/dev/null', GIT_GRAFT_FILE: '/dev/null' },
         stdio: ['ignore', 'pipe', 'pipe'],
       });
 
@@ -168,6 +168,15 @@ it('Git built-ins cannot be overridden by repository shell aliases', () => {
   expect(f.segments().length).toBeGreaterThan(0);
   expect(existsSync(join(f.dir, 'alias-executed'))).toBe(false);
 });
+it('ignores inherited user Git attributes outside the GIT_ namespace', () => {
+  const f = fixture(); f.write('a.txt', 'ONE\ntwo\nthree\n'); f.commit('P1');
+  const read = () => readHistory(f.dir, f.base).final.map(file => file.contexts);
+  const expected = read(); expect(expected.flat()).not.toHaveLength(0);
+  const home = mkdtempSync(join(tmpdir(), 'codeboost-history-home-')); dirs.push(home);
+  mkdirSync(join(home, 'git')); writeFileSync(join(home, 'git', 'attributes'), '* -diff\n');
+  vi.stubEnv('XDG_CONFIG_HOME', home); vi.stubEnv('HOME', home);
+  try { expect(read()).toEqual(expected); } finally { vi.unstubAllEnvs(); }
+});
 it('isolates repository selection from inherited Git environment variables', () => {
   const expected = fixture(); expected.write('a.txt', 'expected repo\n'); expected.commit('P1');
   const foreign = fixture(); foreign.write('a.txt', 'foreign repo\n'); foreign.commit();