diff --git a/internal/executor/gitsync.go b/internal/executor/gitsync.go
new file mode 100644
index 0000000..58d5cf9
--- /dev/null
+++ b/internal/executor/gitsync.go
@@ -0,0 +1,158 @@
+package executor
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+)
+
+// runGitSync syncs the current branch with its remote tracking branch.
+func runGitSync(ctx context.Context, req BuiltinRequest) error {
+	return runGitSyncWith(ctx, req, execGitRunner{})
+}
+
+func runGitSyncWith(ctx context.Context, req BuiltinRequest, runner gitRunner) error {
+	branch, err := currentBranch(ctx, runner)
+	if err != nil {
+		return err
+	}
+
+	// Detect remote branch name (main or master)
+	remoteBranch, err := detectRemoteBranch(ctx, runner, branch)
+	if err != nil {
+		return err
+	}
+
+	fmt.Fprintf(req.Stdout, "同步分支: %s -> %s\n\n", branch, remoteBranch)
+
+	// Fetch first
+	fmt.Fprintf(req.Stdout, "正在 fetch...\n")
+	if _, stderr, err := runner.Run(ctx, "fetch", "origin"); err != nil {
+		return fmt.Errorf("fetch 失败: %w\n%s", err, stderr)
+	}
+
+	// Check if there are changes to rebase
+	localOut, _, _ := runner.Run(ctx, "rev-parse", "HEAD")
+	remoteOut, _, _ := runner.Run(ctx, "rev-parse", remoteBranch)
+
+	local := strings.TrimSpace(localOut)
+	remote := strings.TrimSpace(remoteOut)
+
+	if local == remote {
+		fmt.Fprintf(req.Stdout, "\n✓ 已经是最新，无需同步\n")
+		return nil
+	}
+
+	// Check if we can fast-forward
+	baseOut, _, _ := runner.Run(ctx, "merge-base", "HEAD", remoteBranch)
+	base := strings.TrimSpace(baseOut)
+
+	if base == local {
+		// Can fast-forward
+		fmt.Fprintf(req.Stdout, "正在 fast-forward 到 %s...\n", remoteBranch)
+		if _, stderr, err := runner.Run(ctx, "merge", "--ff-only", remoteBranch); err != nil {
+			return fmt.Errorf("merge 失败: %w\n%s", err, stderr)
+		}
+		fmt.Fprintf(req.Stdout, "\n✓ 已同步到远程\n")
+	} else {
+		// Need rebase
+		fmt.Fprintf(req.Stdout, "正在 rebase 到 %s...\n", remoteBranch)
+		if _, stderr, err := runner.Run(ctx, "rebase", remoteBranch); err != nil {
+			return fmt.Errorf("rebase 失败: %w\n%s\n\n提示: 如有冲突，请手动解决后执行 git rebase --continue", err, stderr)
+		}
+		fmt.Fprintf(req.Stdout, "\n✓ 已 rebase 到远程\n")
+	}
+
+	return nil
+}
+
+// runGitDiscard discards all local changes and resets to remote.
+func runGitDiscard(ctx context.Context, req BuiltinRequest) error {
+	return runGitDiscardWith(ctx, req, execGitRunner{})
+}
+
+func runGitDiscardWith(ctx context.Context, req BuiltinRequest, runner gitRunner) error {
+	confirmed := false
+	for _, arg := range req.Args {
+		if arg == "--yes" || arg == "-y" {
+			confirmed = true
+		}
+	}
+	confirmed = confirmed || req.Confirmed
+
+	branch, err := currentBranch(ctx, runner)
+	if err != nil {
+		return err
+	}
+
+	// Detect remote branch name
+	remoteBranch, err := detectRemoteBranch(ctx, runner, branch)
+	if err != nil {
+		return err
+	}
+
+	// Check for local changes
+	statusOut, _, _ := runner.Run(ctx, "status", "--porcelain")
+	hasChanges := strings.TrimSpace(statusOut) != ""
+
+	// Show preview
+	fmt.Fprintf(req.Stdout, "放弃本地所有改动，以远程为主\n\n")
+	fmt.Fprintf(req.Stdout, "分支: %s -> %s\n", branch, remoteBranch)
+
+	if hasChanges {
+		fmt.Fprintf(req.Stdout, "\n⚠️  以下本地改动将被丢弃:\n")
+		lines := strings.Split(strings.TrimSpace(statusOut), "\n")
+		count := 0
+		for _, line := range lines {
+			if count < 10 {
+				fmt.Fprintf(req.Stdout, "  %s\n", line)
+			}
+			count++
+		}
+		if count > 10 {
+			fmt.Fprintf(req.Stdout, "  ... 还有 %d 个文件\n", count-10)
+		}
+	} else {
+		fmt.Fprintf(req.Stdout, "\n工作区干净，将重置到远程分支\n")
+	}
+
+	if !confirmed {
+		fmt.Fprintf(req.Stdout, "\n⚠️  这是破坏性操作，将永久丢弃所有本地改动！加 --yes 确认执行。\n")
+		return &ExitError{Code: 2, Err: errors.New("需要确认")}
+	}
+
+	// Fetch first
+	fmt.Fprintf(req.Stdout, "\n正在 fetch...\n")
+	if _, stderr, err := runner.Run(ctx, "fetch", "origin"); err != nil {
+		return fmt.Errorf("fetch 失败: %w\n%s", err, stderr)
+	}
+
+	// Reset hard to remote
+	if _, stderr, err := runner.Run(ctx, "reset", "--hard", remoteBranch); err != nil {
+		return fmt.Errorf("reset 失败: %w\n%s", err, stderr)
+	}
+
+	// Clean untracked files
+	runner.Run(ctx, "clean", "-fd")
+
+	fmt.Fprintf(req.Stdout, "\n✓ 已重置到 %s，所有本地改动已丢弃\n", remoteBranch)
+	return nil
+}
+
+// detectRemoteBranch detects whether the remote tracking branch is main or master.
+func detectRemoteBranch(ctx context.Context, runner gitRunner, localBranch string) (string, error) {
+	// Try main first
+	if _, _, err := runner.Run(ctx, "rev-parse", "origin/main"); err == nil {
+		return "origin/main", nil
+	}
+	// Try master
+	if _, _, err := runner.Run(ctx, "rev-parse", "origin/master"); err == nil {
+		return "origin/master", nil
+	}
+	// Try the same branch name on remote
+	if _, _, err := runner.Run(ctx, "rev-parse", fmt.Sprintf("origin/%s", localBranch)); err == nil {
+		return fmt.Sprintf("origin/%s", localBranch), nil
+	}
+	return "", fmt.Errorf("无法检测到远程分支（尝试了 origin/main、origin/master、origin/%s）", localBranch)
+}