Make QR session login scriptable

Allow operators to choose QR login directly with a --qr flag instead of navigating the interactive login-method prompt. Keep the existing prompt as the default for backwards compatibility, and add --phone for symmetric explicit selection.

Constraint: Upstream already has QR login support; the missing piece is a non-interactive CLI selector for operational runbooks.
Rejected: Adding a separate QR generator script | duplicates existing session generator logic and increases maintenance surface.
Confidence: high
Scope-risk: narrow
Directive: Keep session strings private; do not log generated session strings in automated wrappers.
Tested: uv run black --check session_string_generator.py tests/test_session_string_generator.py; uv run pytest tests/test_session_string_generator.py -q; uv run pytest -q
Not-tested: Real Telegram QR authorization, because it requires live account interaction.

Author: iqdoctor

session_string_generator.py

@@ -8,6 +8,7 @@
 
 Usage:
     python session_string_generator.py
+    python session_string_generator.py --qr
 
 Requirements:
     - telethon
@@ -19,6 +20,7 @@
 and usernames (e.g., "@mychannel").
 """
 
+import argparse
 import asyncio
 import io
 import os
@@ -33,6 +35,24 @@
 load_dotenv()
 
 
+def _parse_args() -> argparse.Namespace:
+    parser = argparse.ArgumentParser(
+        description="Generate a Telegram session string for telegram-mcp."
+    )
+    login_group = parser.add_mutually_exclusive_group()
+    login_group.add_argument(
+        "--qr",
+        action="store_true",
+        help="Use Telegram QR login without prompting for a login method.",
+    )
+    login_group.add_argument(
+        "--phone",
+        action="store_true",
+        help="Use phone number + verification code login without prompting for a login method.",
+    )
+    return parser.parse_args()
+
+
 def _check_installation() -> None:
     try:
         assert_safe_distribution()
@@ -99,6 +119,7 @@ def _phone_login(client: TelegramClient) -> None:
 
 
 def main() -> None:
+    args = _parse_args()
     _check_installation()
 
     API_ID = os.getenv("TELEGRAM_API_ID")
@@ -128,10 +149,15 @@ def main() -> None:
         .lower()
     )
 
-    print("\nChoose login method:")
-    print("  1) QR code login (recommended -- scan from your Telegram app)")
-    print("  2) Phone number + verification code")
-    method = input("\nEnter 1 or 2 [default: 1]: ").strip() or "1"
+    if args.qr:
+        method = "1"
+    elif args.phone:
+        method = "2"
+    else:
+        print("\nChoose login method:")
+        print("  1) QR code login (recommended -- scan from your Telegram app)")
+        print("  2) Phone number + verification code")
+        method = input("\nEnter 1 or 2 [default: 1]: ").strip() or "1"
 
     try:
         client = TelegramClient(StringSession(), API_ID, API_HASH)

tests/test_session_string_generator.py

@@ -0,0 +1,37 @@
+import pytest
+
+import session_string_generator
+
+
+def test_parse_args_qr_selects_qr_login(monkeypatch):
+    monkeypatch.setattr("sys.argv", ["session_string_generator.py", "--qr"])
+
+    args = session_string_generator._parse_args()
+
+    assert args.qr is True
+    assert args.phone is False
+
+
+def test_parse_args_phone_selects_phone_login(monkeypatch):
+    monkeypatch.setattr("sys.argv", ["session_string_generator.py", "--phone"])
+
+    args = session_string_generator._parse_args()
+
+    assert args.qr is False
+    assert args.phone is True
+
+
+def test_parse_args_without_flags_keeps_interactive_login_choice(monkeypatch):
+    monkeypatch.setattr("sys.argv", ["session_string_generator.py"])
+
+    args = session_string_generator._parse_args()
+
+    assert args.qr is False
+    assert args.phone is False
+
+
+def test_parse_args_rejects_conflicting_login_modes(monkeypatch):
+    monkeypatch.setattr("sys.argv", ["session_string_generator.py", "--qr", "--phone"])
+
+    with pytest.raises(SystemExit):
+        session_string_generator._parse_args()