diff --git a/PRD.md b/PRD.md
index cc4cdf1..e7802ea 100644
--- a/PRD.md
+++ b/PRD.md
@@ -2,6 +2,6 @@
 Ein Starter Projekt in go
 ## Tasks
 
-- [ ] Erstelle eine Datei hello.go mit einem Hello World Programm
+- [x] Erstelle eine Datei hello.go die 2 zahlen aus der Kommandozeile einliest und die Summe ausgibt
+- [ ] Erstelle unit tests für hello.go
 - [ ] Erstelle eine Datei README.md mit einer kurzen Projektbeschreibung
-- [ ] Projektstruktur anlegen
diff --git a/agent/tools.go b/agent/tools.go
index f22bae7..816216e 100644
--- a/agent/tools.go
+++ b/agent/tools.go
@@ -1,260 +1,3 @@
-// package agent
-
-// import (
-// 	"fmt"
-// 	"os"
-// 	"path/filepath"
-// 	"strings"
-// )
-
-// // ─── Tool Registry ────────────────────────────────────────
-
-// type Tool struct {
-// 	Name        string
-// 	Description string
-// 	Usage       string
-// }
-
-// var Registry = []Tool{
-// 	{
-// 		Name:        "READ_FILE",
-// 		Description: "Liest den Inhalt einer Datei",
-// 		Usage:       "TOOL:READ_FILE:pfad/zur/datei",
-// 	},
-// 	{
-// 		Name:        "WRITE_FILE",
-// 		Description: "Schreibt Inhalt in eine Datei (mehrzeilig möglich)",
-// 		Usage: `TOOL:WRITE_FILE:pfad/zur/datei
-// <<<
-// dateiinhalt hier
-// >>>`,
-// 	},
-// 	{
-// 		Name:        "LIST_FILES",
-// 		Description: "Listet alle Dateien in einem Verzeichnis",
-// 		Usage:       "TOOL:LIST_FILES:pfad",
-// 	},
-// }
-
-// // BuildToolPrompt generiert den Tool-Abschnitt für den System-Prompt
-// func BuildToolPrompt() string {
-// 	var sb strings.Builder
-// 	sb.WriteString("Du hast folgende Tools zur Verfügung:\n\n")
-// 	for _, t := range Registry {
-// 		sb.WriteString(fmt.Sprintf("### %s\n", t.Name))
-// 		sb.WriteString(fmt.Sprintf("Beschreibung: %s\n", t.Description))
-// 		sb.WriteString(fmt.Sprintf("Verwendung:\n%s\n\n", t.Usage))
-// 	}
-// 	return sb.String()
-// }
-
-// // ─── Tool Parsing ─────────────────────────────────────────
-
-// type toolCall struct {
-// 	name    string
-// 	path    string
-// 	content string // nur für WRITE_FILE
-// }
-
-// // parseToolCalls extrahiert alle Tool-Calls aus einer LLM-Antwort.
-// // Unterstützt mehrzeilige WRITE_FILE Blöcke:
-// //
-// //	TOOL:WRITE_FILE:pfad
-// //	<<<
-// //	inhalt
-// //	>>>
-// func parseToolCalls(response string) []toolCall {
-// 	var calls []toolCall
-// 	lines := strings.Split(response, "\n")
-
-// 	i := 0
-// 	for i < len(lines) {
-// 		line := strings.TrimSpace(lines[i])
-
-// 		if !strings.HasPrefix(line, "TOOL:") {
-// 			i++
-// 			continue
-// 		}
-
-// 		parts := strings.SplitN(line, ":", 3)
-// 		if len(parts) < 3 {
-// 			i++
-// 			continue
-// 		}
-
-// 		toolName := parts[1]
-// 		toolPath := parts[2]
-
-// 		// WRITE_FILE: Block-Inhalt lesen (<<<...>>>)
-// 		if toolName == "WRITE_FILE" {
-// 			content, newIndex := readContentBlock(lines, i+1)
-// 			calls = append(calls, toolCall{
-// 				name:    toolName,
-// 				path:    toolPath,
-// 				content: content,
-// 			})
-// 			i = newIndex
-// 			continue
-// 		}
-
-// 		calls = append(calls, toolCall{
-// 			name: toolName,
-// 			path: toolPath,
-// 		})
-// 		i++
-// 	}
-
-// 	return calls
-// }
-
-// // readContentBlock liest Zeilen zwischen <<< und >>> und gibt den
-// // bereinigten Inhalt sowie den neuen Zeilenindex zurück.
-// func readContentBlock(lines []string, startIndex int) (string, int) {
-// 	i := startIndex
-
-// 	// Öffnendes <<< überspringen (optional, falls LLM es ausgibt)
-// 	if i < len(lines) && strings.TrimSpace(lines[i]) == "<<<" {
-// 		i++
-// 	}
-
-// 	var contentLines []string
-// 	for i < len(lines) {
-// 		trimmed := strings.TrimSpace(lines[i])
-// 		if trimmed == ">>>" {
-// 			i++ // >>> konsumieren
-// 			break
-// 		}
-// 		contentLines = append(contentLines, lines[i])
-// 		i++
-// 	}
-
-// 	return strings.Join(contentLines, "\n"), i
-// }
-
-// // ─── Tool Execution ───────────────────────────────────────
-
-// // ExecuteTools parst alle Tool-Calls aus der LLM-Antwort und führt sie aus.
-// // Gibt den kombinierten Output und true zurück wenn mindestens ein Tool aufgerufen wurde.
-// func ExecuteTools(response string, workDir string) (string, bool) {
-// 	calls := parseToolCalls(response)
-// 	if len(calls) == 0 {
-// 		return "", false
-// 	}
-
-// 	var outputs []string
-// 	for _, call := range calls {
-// 		result := executeToolCall(call, workDir)
-// 		outputs = append(outputs, result)
-// 	}
-
-// 	return strings.Join(outputs, "\n"), true
-// }
-
-// func executeToolCall(call toolCall, workDir string) string {
-// 	// Sicherheits-Check: Path Traversal verhindern
-// 	safePath, err := sanitizePath(workDir, call.path)
-// 	if err != nil {
-// 		return fmt.Sprintf("ERROR: Ungültiger Pfad %q: %v", call.path, err)
-// 	}
-
-// 	switch call.name {
-// 	case "READ_FILE":
-// 		return readFile(safePath, call.path)
-// 	case "WRITE_FILE":
-// 		return writeFile(safePath, call.path, call.content)
-// 	case "LIST_FILES":
-// 		return listFiles(safePath, call.path)
-// 	default:
-// 		return fmt.Sprintf("ERROR: Unbekanntes Tool %q", call.name)
-// 	}
-// }
-
-// // ─── Einzelne Tool-Implementierungen ─────────────────────
-
-// func readFile(absPath, displayPath string) string {
-// 	content, err := os.ReadFile(absPath)
-// 	if err != nil {
-// 		return fmt.Sprintf("READ_FILE ERROR: %v", err)
-// 	}
-// 	return fmt.Sprintf("READ_FILE %s:\n%s", displayPath, string(content))
-// }
-
-// func writeFile(absPath, displayPath, content string) string {
-// 	content = cleanContent(content)
-// 	if err := os.MkdirAll(filepath.Dir(absPath), 0755); err != nil {
-// 		return fmt.Sprintf("WRITE_FILE ERROR: Verzeichnis anlegen fehlgeschlagen: %v", err)
-// 	}
-// 	if err := os.WriteFile(absPath, []byte(content), 0644); err != nil {
-// 		return fmt.Sprintf("WRITE_FILE ERROR: %v", err)
-// 	}
-// 	return fmt.Sprintf("WRITE_FILE OK: %s geschrieben (%d Bytes)", displayPath, len(content))
-// }
-
-// func listFiles(absPath, displayPath string) string {
-// 	entries, err := os.ReadDir(absPath)
-// 	if err != nil {
-// 		return fmt.Sprintf("LIST_FILES ERROR: %v", err)
-// 	}
-// 	if len(entries) == 0 {
-// 		return fmt.Sprintf("LIST_FILES %s: (leer)", displayPath)
-// 	}
-// 	var files []string
-// 	for _, e := range entries {
-// 		if e.IsDir() {
-// 			files = append(files, e.Name()+"/")
-// 		} else {
-// 			files = append(files, e.Name())
-// 		}
-// 	}
-// 	return fmt.Sprintf("LIST_FILES %s:\n%s", displayPath, strings.Join(files, "\n"))
-// }
-
-// // ─── Sicherheit ───────────────────────────────────────────
-
-// // sanitizePath stellt sicher dass der Pfad innerhalb des workDir bleibt.
-// // Verhindert Directory Traversal wie ../../etc/passwd
-// func sanitizePath(workDir, relPath string) (string, error) {
-// 	// Wenn LLM einen absoluten Pfad schickt → relativen Teil extrahieren
-// 	if filepath.IsAbs(relPath) {
-// 		workDirClean := filepath.Clean(workDir)
-// 		// Prüfen ob der absolute Pfad innerhalb des workDir liegt
-// 		if strings.HasPrefix(relPath, workDirClean) {
-// 			// Absoluten Pfad direkt nutzen, kein Join nötig
-// 			return filepath.Clean(relPath), nil
-// 		}
-// 		// Absoluter Pfad außerhalb workDir → nur Dateiname nehmen
-// 		relPath = filepath.Base(relPath)
-// 	}
-
-// 	// Normaler Fall: relativer Pfad
-// 	abs := filepath.Clean(filepath.Join(workDir, relPath))
-// 	workDirClean := filepath.Clean(workDir)
-
-// 	if !strings.HasPrefix(abs, workDirClean+string(filepath.Separator)) &&
-// 		abs != workDirClean {
-// 		return "", fmt.Errorf("Pfad außerhalb des Arbeitsverzeichnisses")
-// 	}
-
-// 	return abs, nil
-// }
-
-// func cleanContent(content string) string {
-// 	// Escaped Quotes normalisieren
-// 	content = strings.ReplaceAll(content, `\"`, `"`)
-// 	content = strings.ReplaceAll(content, `\\n`, "\n")
-// 	content = strings.ReplaceAll(content, `\\t`, "\t")
-
-//		// Markdown Codeblöcke entfernen
-//		lines := strings.Split(content, "\n")
-//		var cleaned []string
-//		for _, line := range lines {
-//			if strings.HasPrefix(strings.TrimSpace(line), "```") {
-//				continue
-//			}
-//			cleaned = append(cleaned, line)
-//		}
-//		return strings.TrimSpace(strings.Join(cleaned, "\n"))
-//	}
 package agent
 
 import (
@@ -320,6 +63,10 @@ var Tools = []openai.ChatCompletionToolParam{
 						"type":        "string",
 						"description": "Relativer Verzeichnispfad, '.' für aktuelles Verzeichnis",
 					},
+					"recursive": map[string]any{
+						"type":        "boolean",
+						"description": "true = alle Unterverzeichnisse rekursiv auflisten",
+					},
 				},
 				"required": []string{"path"},
 			},
@@ -338,7 +85,7 @@ var Tools = []openai.ChatCompletionToolParam{
 	},
 }
 
-// ─── Tool Execution ───────────────────────────────────────
+// ─── Tool Executor ────────────────────────────────────────
 
 type ToolExecutor struct {
 	workDir string
@@ -379,12 +126,13 @@ func (e *ToolExecutor) Execute(toolCall openai.ChatCompletionMessageToolCall) (s
 
 	case "list_files":
 		var p struct {
-			Path string `json:"path"`
+			Path      string `json:"path"`
+			Recursive bool   `json:"recursive"`
 		}
 		if err := json.Unmarshal([]byte(args), &p); err != nil {
 			return fmt.Sprintf("ERROR: Ungültige Parameter: %v", err), false
 		}
-		return e.listFiles(p.Path), false
+		return e.listFiles(p.Path, p.Recursive), false
 	}
 
 	return fmt.Sprintf("ERROR: Unbekanntes Tool %q", name), false
@@ -418,27 +166,66 @@ func (e *ToolExecutor) readFile(relPath string) string {
 	return fmt.Sprintf("OK: Inhalt von %s:\n%s", relPath, string(content))
 }
 
-func (e *ToolExecutor) listFiles(relPath string) string {
+func (e *ToolExecutor) listFiles(relPath string, recursive bool) string {
 	absPath, err := e.sanitizePath(relPath)
 	if err != nil {
 		return fmt.Sprintf("ERROR: %v", err)
 	}
+	if recursive {
+		return e.listFilesRecursive(absPath, relPath)
+	}
+	return e.listFilesFlat(absPath, relPath)
+}
+
+func (e *ToolExecutor) listFilesFlat(absPath, displayPath string) string {
 	entries, err := os.ReadDir(absPath)
 	if err != nil {
 		return fmt.Sprintf("ERROR: Verzeichnis nicht lesbar: %v", err)
 	}
 	if len(entries) == 0 {
-		return fmt.Sprintf("OK: %s ist leer", relPath)
+		return fmt.Sprintf("OK: %s ist leer", displayPath)
 	}
 	var files []string
-	for _, e := range entries {
-		if e.IsDir() {
-			files = append(files, e.Name()+"/")
+	for _, entry := range entries {
+		if entry.IsDir() {
+			files = append(files, entry.Name()+"/")
 		} else {
-			files = append(files, e.Name())
+			files = append(files, entry.Name())
 		}
 	}
-	return fmt.Sprintf("OK: Dateien in %s:\n%s", relPath, strings.Join(files, "\n"))
+	return fmt.Sprintf("OK: Dateien in %s:\n%s", displayPath, strings.Join(files, "\n"))
+}
+
+func (e *ToolExecutor) listFilesRecursive(absPath, displayPath string) string {
+	var files []string
+
+	err := filepath.WalkDir(absPath, func(path string, d os.DirEntry, err error) error {
+		if err != nil {
+			return err
+		}
+		rel, err := filepath.Rel(e.workDir, path)
+		if err != nil {
+			return err
+		}
+		if rel == "." {
+			return nil
+		}
+		if d.IsDir() {
+			files = append(files, rel+"/")
+		} else {
+			files = append(files, rel)
+		}
+		return nil
+	})
+
+	if err != nil {
+		return fmt.Sprintf("ERROR: %v", err)
+	}
+	if len(files) == 0 {
+		return fmt.Sprintf("OK: %s ist leer", displayPath)
+	}
+	return fmt.Sprintf("OK: Dateien in %s (rekursiv):\n%s",
+		displayPath, strings.Join(files, "\n"))
 }
 
 // ─── Sicherheit ───────────────────────────────────────────