diff --git a/cli/main.go b/cli/main.go
index 200bb14..5b8ce93 100644
--- a/cli/main.go
+++ b/cli/main.go
@@ -1,7 +1,163 @@
 package main
 
-import "fmt"
+import (
+	"flag"
+	"fmt"
+	"os"
+	"strings"
+)
 
 func main() {
-	fmt.Println("msdl — Windows ISO downloader")
+	if err := run(os.Args[1:]); err != nil {
+		fmt.Fprintln(os.Stderr, "error:", err)
+		os.Exit(1)
+	}
+}
+
+func run(args []string) error {
+	fs := flag.NewFlagSet("msdl", flag.ContinueOnError)
+	fs.SetOutput(os.Stderr)
+	fs.Usage = func() {
+		fmt.Fprintln(os.Stderr, `msdl — Windows ISO downloader
+
+Usage:
+  msdl [search terms]                           interactive: filter + pick product, pick language
+  msdl --id 3262                                skip product picker
+  msdl --id 3262 --lang "English (United States)"  no prompts, print URL directly
+  msdl --eval [slug]                            evaluation ISOs (server-2025, win11-ent, ...)
+  msdl --list                                   list all products and exit
+
+Flags:`)
+		fs.PrintDefaults()
+	}
+
+	productID := fs.String("id", "", "consumer product ID (skips product picker)")
+	langFlag := fs.String("lang", "", `language name, e.g. "English (United States)"`)
+	evalMode := fs.Bool("eval", false, "fetch evaluation ISOs")
+	listMode := fs.Bool("list", false, "list all products and exit")
+
+	if err := fs.Parse(args); err != nil {
+		return err
+	}
+	query := strings.Join(fs.Args(), " ")
+
+	if *listMode {
+		fmt.Fprintln(os.Stderr, "Consumer products:")
+		for _, p := range consumerProducts {
+			fmt.Fprintf(os.Stderr, "  %-6s %s\n", p.ID, p.Name)
+		}
+		fmt.Fprintln(os.Stderr, "\nEvaluation products:")
+		for _, p := range evalProducts {
+			fmt.Fprintf(os.Stderr, "  %-20s %s\n", p.Slug, p.Name)
+		}
+		return nil
+	}
+
+	if *evalMode {
+		return runEval(query)
+	}
+	return runConsumer(*productID, query, *langFlag)
+}
+
+func runConsumer(productID, query, langName string) error {
+	var product Product
+
+	if productID != "" {
+		p, ok := findProductByID(productID)
+		if !ok {
+			return fmt.Errorf("unknown product ID %q — run msdl --list to see all products", productID)
+		}
+		product = p
+	} else {
+		candidates := consumerProducts
+		if query != "" {
+			candidates = searchProducts(query)
+			if len(candidates) == 0 {
+				return fmt.Errorf("no products match %q — run msdl --list to see all products", query)
+			}
+		}
+		if len(candidates) == 1 {
+			product = candidates[0]
+			fmt.Fprintf(os.Stderr, "Selected: %s\n", product.Name)
+		} else {
+			var err error
+			product, err = pickProduct(candidates)
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Setting up Microsoft session...\n")
+	client, sessionID := newSession()
+
+	langs, err := fetchLanguages(client, sessionID, product.ID)
+	if err != nil {
+		return fmt.Errorf("fetching languages for %s: %w", product.Name, err)
+	}
+
+	var lang Language
+	if langName != "" {
+		for _, l := range langs {
+			if strings.EqualFold(l.Language, langName) {
+				lang = l
+				break
+			}
+		}
+		if lang.ID == "" {
+			return fmt.Errorf("language %q not available for %s", langName, product.Name)
+		}
+	} else {
+		lang, err = pickLanguage(langs)
+		if err != nil {
+			return err
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Fetching download link...\n")
+	links, err := fetchDownloadLinks(client, sessionID, product.ID, lang.ID)
+	if err != nil {
+		return fmt.Errorf("fetching download links: %w", err)
+	}
+
+	for _, link := range links {
+		fmt.Println(link.URI)
+	}
+	return nil
+}
+
+func runEval(slug string) error {
+	var ep EvalProduct
+
+	if slug != "" {
+		p, ok := findEvalProduct(slug)
+		if !ok {
+			return fmt.Errorf("unknown eval product %q — valid slugs: server-2025, server-2022, server-2019, server-2016, win11-ent", slug)
+		}
+		ep = p
+	} else {
+		var err error
+		ep, err = pickEvalProduct(evalProducts)
+		if err != nil {
+			return err
+		}
+	}
+
+	fmt.Fprintf(os.Stderr, "Fetching eval links for %s...\n", ep.Name)
+	links, err := fetchEvalLinks(ep.EvalURL)
+	if err != nil {
+		return fmt.Errorf("fetching eval links for %s: %w", ep.Name, err)
+	}
+	if len(links) == 0 {
+		return fmt.Errorf("no eval links returned for %s", ep.Slug)
+	}
+
+	for _, link := range links {
+		if link.Arch != "" {
+			fmt.Printf("%s\t%s\n", link.Arch, link.URL)
+		} else {
+			fmt.Println(link.URL)
+		}
+	}
+	return nil
 }