diff --git a/homelab-ai-bot/tools/api_costs.py b/homelab-ai-bot/tools/api_costs.py
new file mode 100644
index 00000000..205a5a4d
--- /dev/null
+++ b/homelab-ai-bot/tools/api_costs.py
@@ -0,0 +1,84 @@
+"""API-Kosten Tool — OpenRouter Guthaben und Verbrauch abfragen."""
+
+import requests
+from core import config
+
+TOOLS = [
+    {
+        "type": "function",
+        "function": {
+            "name": "get_api_costs",
+            "description": "OpenRouter API-Kosten und Guthaben abfragen. Zeigt Verbrauch (heute/Woche/Monat), Restguthaben und Hochrechnung.",
+            "parameters": {
+                "type": "object",
+                "properties": {},
+            },
+        },
+    },
+]
+
+
+def _get_key():
+    cfg = config.parse_config()
+    return cfg.api_keys.get("openrouter_key", "")
+
+
+def handle_get_api_costs(**kw):
+    key = _get_key()
+    if not key:
+        return "OpenRouter API Key fehlt in homelab.conf"
+
+    headers = {"Authorization": f"Bearer {key}"}
+
+    try:
+        r_key = requests.get("https://openrouter.ai/api/v1/auth/key",
+                             headers=headers, timeout=10)
+        r_key.raise_for_status()
+        key_data = r_key.json().get("data", {})
+    except Exception as e:
+        return f"API-Abfrage fehlgeschlagen: {e}"
+
+    try:
+        r_credits = requests.get("https://openrouter.ai/api/v1/credits",
+                                 headers=headers, timeout=10)
+        r_credits.raise_for_status()
+        credit_data = r_credits.json().get("data", {})
+    except Exception:
+        credit_data = {}
+
+    usage_daily = key_data.get("usage_daily", 0)
+    usage_weekly = key_data.get("usage_weekly", 0)
+    usage_monthly = key_data.get("usage_monthly", 0)
+    total_credits = credit_data.get("total_credits", 0)
+    total_usage = credit_data.get("total_usage", 0)
+    remaining = total_credits - total_usage if total_credits else None
+
+    monthly_forecast = usage_daily * 30 if usage_daily > 0 else 0
+
+    lines = [
+        "OpenRouter API-Kosten",
+        "",
+        f"Heute:  ${usage_daily:.4f}",
+        f"Woche:  ${usage_weekly:.4f}",
+        f"Monat:  ${usage_monthly:.4f}",
+    ]
+
+    if monthly_forecast > 0:
+        lines.append(f"Prognose (30d): ${monthly_forecast:.2f}")
+
+    lines.append("")
+
+    if remaining is not None:
+        lines.append(f"Guthaben: ${total_credits:.2f}")
+        lines.append(f"Verbraucht: ${total_usage:.2f}")
+        lines.append(f"Restguthaben: ${remaining:.2f}")
+        if usage_daily > 0 and remaining > 0:
+            days_left = remaining / usage_daily
+            lines.append(f"Reicht noch: ~{days_left:.0f} Tage (bei aktuellem Verbrauch)")
+    else:
+        lines.append("Guthaben: unbegrenzt (kein Limit gesetzt)")
+
+    return "\n".join(lines)
+
+
+HANDLERS = {"get_api_costs": handle_get_api_costs}