diff --git a/src/git/diff.ts b/src/git/diff.ts
index 64a2cc0..b03a19a 100644
--- a/src/git/diff.ts
+++ b/src/git/diff.ts
@@ -1,7 +1,17 @@
-import { execSync, spawnSync } from 'node:child_process';
-import { writeFileSync, unlinkSync } from 'node:fs';
+import { execFileSync, spawnSync } from 'node:child_process';
+import {
+  accessSync,
+  copyFileSync,
+  existsSync,
+  constants,
+  mkdtempSync,
+  rmSync,
+  statSync,
+  writeFileSync,
+  unlinkSync,
+} from 'node:fs';
 import { tmpdir } from 'node:os';
-import { join, normalize } from 'node:path';
+import { delimiter, isAbsolute, join, normalize, resolve } from 'node:path';
 
 export interface DiffResult {
   diff: string;
@@ -16,14 +26,84 @@ export interface CommitResult {
 }
 
 const GIT_DIFF_MAX_BUFFER = 100 * 1024 * 1024;
+const GIT_EXECUTABLE_NAME = process.platform === 'win32' ? 'git.exe' : 'git';
+let gitExecutable: string | undefined;
+
+function isExecutableFile(path: string): boolean {
+  try {
+    accessSync(path, constants.X_OK);
+    return statSync(path).isFile();
+  } catch {
+    return false;
+  }
+}
+
+function getGitExecPathCandidates(gitExecPath: string | undefined): string[] {
+  if (!gitExecPath || !isAbsolute(gitExecPath)) {
+    return [];
+  }
+
+  return process.platform === 'win32'
+    ? [join(gitExecPath, '..', '..', GIT_EXECUTABLE_NAME)]
+    : [join(gitExecPath, '..', '..', 'bin', GIT_EXECUTABLE_NAME)];
+}
+
+function getWindowsGitCandidates(): string[] {
+  const programFiles = [
+    process.env.ProgramFiles,
+    process.env['ProgramFiles(x86)'],
+    String.raw`C:\Program Files`,
+  ].filter((value): value is string => Boolean(value));
+  const programFileCandidates = programFiles.flatMap((root) => [
+    join(root, 'Git', 'cmd', GIT_EXECUTABLE_NAME),
+    join(root, 'Git', 'mingw64', 'bin', GIT_EXECUTABLE_NAME),
+  ]);
+  const localAppData = process.env.LOCALAPPDATA;
+
+  return localAppData
+    ? [...programFileCandidates, join(localAppData, 'Programs', 'Git', 'cmd', GIT_EXECUTABLE_NAME)]
+    : programFileCandidates;
+}
+
+function getUnixGitCandidates(): string[] {
+  return ['/usr/bin/git', '/usr/local/bin/git', '/opt/homebrew/bin/git', '/opt/local/bin/git', '/bin/git'];
+}
+
+function getPathGitCandidates(): string[] {
+  const pathValue = process.env.PATH ?? process.env.Path ?? '';
+  return pathValue
+    .split(delimiter)
+    .map((directory) => resolve(process.cwd(), directory || '.', GIT_EXECUTABLE_NAME));
+}
+
+function resolveGitExecutable(): string {
+  const candidates = [
+    ...getGitExecPathCandidates(process.env.GIT_EXEC_PATH),
+    ...getPathGitCandidates(),
+    ...(process.platform === 'win32' ? getWindowsGitCandidates() : getUnixGitCandidates()),
+  ].map((candidate) => resolve(candidate));
+  const executable = candidates.find(isExecutableFile);
+
+  if (!executable) {
+    throw new Error('git is not installed or not found in a supported location');
+  }
+
+  return normalize(executable);
+}
+
+function getGitExecutable(): string {
+  gitExecutable ??= resolveGitExecutable();
+  return gitExecutable;
+}
 
 export function checkGitRepo(): void {
+  const executable = getGitExecutable();
   try {
-    execSync('git rev-parse --git-dir', { encoding: 'utf-8', stdio: 'pipe' });
+    execFileSync(executable, ['rev-parse', '--git-dir'], { encoding: 'utf-8', stdio: 'pipe' });
   } catch (err) {
     const nodeErr = err as NodeJS.ErrnoException & { stderr?: string };
     if (nodeErr.code === 'ENOENT') {
-      throw new Error('git is not installed or not found on PATH');
+      throw new Error('git is not installed or not found in a supported location');
     }
     const stderr = nodeErr.stderr?.trim();
     throw new Error(stderr || 'Not a git repository');
@@ -32,7 +112,7 @@ export function checkGitRepo(): void {
 
 export function hasCommits(): boolean {
   try {
-    const count = execSync('git rev-list --count HEAD', {
+    const count = execFileSync(getGitExecutable(), ['rev-list', '--count', 'HEAD'], {
       encoding: 'utf-8',
       stdio: 'pipe',
     }).trim();
@@ -44,7 +124,7 @@ export function hasCommits(): boolean {
 }
 
 export function getStagedDiff(): DiffResult {
-  const diff = execSync('git diff --cached', {
+  const diff = execFileSync(getGitExecutable(), ['diff', '--cached'], {
     encoding: 'utf-8',
     maxBuffer: GIT_DIFF_MAX_BUFFER,
   });
@@ -55,14 +135,93 @@ export function getStagedDiff(): DiffResult {
   };
 }
 
+function getGitPath(path: string): string {
+  return resolve(
+    execFileSync(getGitExecutable(), ['rev-parse', '--git-path', path], {
+      encoding: 'utf-8',
+      stdio: 'pipe',
+    }).trim(),
+  );
+}
+
+function getUntrackedDiff(): string {
+  const untrackedEntries = execFileSync(getGitExecutable(), ['ls-files', '--others', '--exclude-standard', '-z'], {
+    encoding: 'utf-8',
+    maxBuffer: GIT_DIFF_MAX_BUFFER,
+  })
+    .split('\0')
+    .filter(Boolean);
+  if (untrackedEntries.length === 0) {
+    return '';
+  }
+
+  const pathspecs = untrackedEntries.filter((entry) => {
+    if (!entry.endsWith('/')) {
+      return true;
+    }
+
+    try {
+      execFileSync(getGitExecutable(), ['rev-parse', '--verify', 'HEAD'], {
+        cwd: resolve(entry),
+        encoding: 'utf-8',
+        stdio: 'pipe',
+      });
+      return true;
+    } catch {
+      return false;
+    }
+  });
+  if (pathspecs.length === 0) {
+    return '';
+  }
+
+  const tempDir = mkdtempSync(join(tmpdir(), 'commit-echo-index-'));
+  const tempIndex = join(tempDir, 'index');
+
+  try {
+    const indexPath = getGitPath('index');
+    if (existsSync(indexPath)) {
+      copyFileSync(indexPath, tempIndex);
+    }
+
+    const env = { ...process.env, GIT_INDEX_FILE: tempIndex };
+    const addResult = spawnSync(
+      getGitExecutable(),
+      ['--literal-pathspecs', 'add', '--intent-to-add', '--pathspec-from-file=-', '--pathspec-file-nul'],
+      {
+        encoding: 'utf-8',
+        env,
+        input: `${pathspecs.join('\0')}\0`,
+        maxBuffer: GIT_DIFF_MAX_BUFFER,
+        stdio: 'pipe',
+      },
+    );
+    if (addResult.error) throw addResult.error;
+    if (addResult.status !== 0) {
+      const detail = [addResult.stderr, addResult.stdout].filter(Boolean).join('\n').trim();
+      throw new Error(detail || `git add --intent-to-add exited with code ${addResult.status}`);
+    }
+
+    return execFileSync(getGitExecutable(), ['--literal-pathspecs', 'diff', '--', ...pathspecs], {
+      encoding: 'utf-8',
+      env,
+      maxBuffer: GIT_DIFF_MAX_BUFFER,
+    });
+  } finally {
+    rmSync(tempDir, { recursive: true, force: true });
+  }
+}
+
 export function getUnstagedDiff(): DiffResult {
-  const diff = execSync('git diff', {
+  const untrackedAwareDiff = getUntrackedDiff();
+  const trackedDiff = execFileSync(getGitExecutable(), ['diff'], {
     encoding: 'utf-8',
     maxBuffer: GIT_DIFF_MAX_BUFFER,
   });
+  const diff = [trackedDiff.trim(), untrackedAwareDiff.trim()].filter(Boolean).join('\n');
   return {
-    diff: diff.trim(),
-    hasChanges: diff.trim().length > 0,
+    diff,
+    hasChanges: diff.length > 0,
     staged: false,
   };
 }
@@ -83,7 +242,7 @@ export function commit(message: string, body?: string): CommitResult {
   const tmpFile = join(tmpdir(), `commit-echo-msg-${process.pid}-${Date.now()}.txt`);
   try {
     writeFileSync(tmpFile, fullMessage, 'utf-8');
-    const result = spawnSync('git', ['commit', '-F', tmpFile], {
+    const result = spawnSync(getGitExecutable(), ['commit', '-F', tmpFile], {
       encoding: 'utf-8',
       shell: false,
     });
@@ -101,12 +260,12 @@ export function commit(message: string, body?: string): CommitResult {
 }
 
 export function getRepoRoot(): string {
-  return normalize(execSync('git rev-parse --show-toplevel', { encoding: 'utf-8' }).trim());
+  return normalize(execFileSync(getGitExecutable(), ['rev-parse', '--show-toplevel'], { encoding: 'utf-8' }).trim());
 }
 
 export function getBranchName(): string {
   try {
-    return execSync('git rev-parse --abbrev-ref HEAD', { encoding: 'utf-8' }).trim();
+    return execFileSync(getGitExecutable(), ['rev-parse', '--abbrev-ref', 'HEAD'], { encoding: 'utf-8' }).trim();
   } catch {
     return 'unknown';
   }
@@ -114,7 +273,10 @@ export function getBranchName(): string {
 
 export function getLastCommitMessage(): string {
   try {
-    return execSync('git log -1 --format=%s', { encoding: 'utf-8', stdio: 'pipe' }).trim();
+    return execFileSync(getGitExecutable(), ['log', '-1', '--format=%s'], {
+      encoding: 'utf-8',
+      stdio: 'pipe',
+    }).trim();
   } catch {
     return '';
   }
diff --git a/tests/git-diff.test.mjs b/tests/git-diff.test.mjs
index fba896f..204c104 100644
--- a/tests/git-diff.test.mjs
+++ b/tests/git-diff.test.mjs
@@ -190,6 +190,95 @@ test("getUnstagedDiff returns diff for unstaged changes", () => {
   }
 });
 
+test("getUnstagedDiff includes untracked files", () => {
+  const repoDir = initRepo();
+
+  try {
+    git(["commit", "--allow-empty", "-m", "initial commit"], repoDir);
+    writeFileSync(join(repoDir, "new-file.txt"), "untracked content\n", "utf-8");
+
+    withCwd(repoDir, () => {
+      const result = getUnstagedDiff();
+
+      assert.equal(result.hasChanges, true);
+      assert.equal(result.staged, false);
+      assert.ok(result.diff.includes("new-file.txt"));
+      assert.ok(result.diff.includes("+untracked content"));
+    });
+  } finally {
+    rmSync(repoDir, { recursive: true, force: true });
+  }
+});
+
+test("getUnstagedDiff combines tracked and untracked changes without duplication", () => {
+  const repoDir = initRepo();
+
+  try {
+    writeFileSync(join(repoDir, "file.txt"), "hello\n", "utf-8");
+    git(["add", "file.txt"], repoDir);
+    git(["commit", "-m", "initial commit"], repoDir);
+    writeFileSync(join(repoDir, "file.txt"), "hello\nworld\n", "utf-8");
+    writeFileSync(join(repoDir, "new-file.txt"), "untracked content\n", "utf-8");
+
+    withCwd(repoDir, () => {
+      const result = getUnstagedDiff();
+      const trackedHunks = result.diff.match(/^diff --git a\/file\.txt b\/file\.txt$/gm) ?? [];
+
+      assert.equal(trackedHunks.length, 1);
+      assert.equal((result.diff.match(/\+world/g) ?? []).length, 1);
+      assert.ok(result.diff.includes("+untracked content"));
+    });
+  } finally {
+    rmSync(repoDir, { recursive: true, force: true });
+  }
+});
+
+test("getUnstagedDiff handles untracked filenames with pathspec magic", { skip: process.platform === "win32" }, () => {
+  const repoDir = initRepo();
+  const filename = ":(top)foo";
+
+  try {
+    git(["commit", "--allow-empty", "-m", "initial commit"], repoDir);
+    writeFileSync(join(repoDir, filename), "untracked content\n", "utf-8");
+
+    withCwd(repoDir, () => {
+      const result = getUnstagedDiff();
+
+      assert.equal(result.hasChanges, true);
+      assert.ok(result.diff.includes(filename));
+      assert.ok(result.diff.includes("+untracked content"));
+    });
+  } finally {
+    rmSync(repoDir, { recursive: true, force: true });
+  }
+});
+
+test("getUnstagedDiff includes an untracked embedded git repository", () => {
+  const repoDir = initRepo();
+
+  try {
+    git(["commit", "--allow-empty", "-m", "initial commit"], repoDir);
+    const nestedRepoDir = join(repoDir, "nested");
+    mkdirSync(nestedRepoDir);
+    git(["init"], nestedRepoDir);
+    writeFileSync(join(nestedRepoDir, "nested-file.txt"), "nested content\n", "utf-8");
+    git(["config", "user.name", "Nested Test User"], nestedRepoDir);
+    git(["config", "user.email", "nested-test@example.com"], nestedRepoDir);
+    git(["add", "nested-file.txt"], nestedRepoDir);
+    git(["commit", "-m", "initial nested commit"], nestedRepoDir);
+
+    withCwd(repoDir, () => {
+      const result = getUnstagedDiff();
+
+      assert.equal(result.hasChanges, true);
+      assert.ok(result.diff.includes("nested"));
+      assert.ok(result.diff.includes("new file mode 160000"));
+    });
+  } finally {
+    rmSync(repoDir, { recursive: true, force: true });
+  }
+});
+
 test("getUnstagedDiff handles diffs larger than the default execSync buffer", () => {
   const repoDir = initRepo();