-device. In the terminal client or in Telegram, the line ``/whatsapp
-status`` shows the link: not linked, linked and connected, or linked and
-disconnected, with the times of the connection. The answer goes only to
-the client that asked, and the line does not go to the agent.
-
-The session is ``whatsapp/session.db`` in the data directory. It gives
-full access to the WhatsApp account, so the daemon refuses the file when
-its mode is not 0600. The shell of the agent runs as the user, so it can
-read the session. If the session leaks, remove the linked device in
-WhatsApp on the phone, and the session stops working. Without the file,
-WhatsApp is not linked. When the session holds a linked device, the
-daemon connects at its start, and after a network failure it connects
-again by itself.
+device. The terminal client and Telegram take three commands:
+
+``/whatsapp pair PHONE``
+ Links the account of PHONE, the number with its country code, such as
+ ``+15550001111``. The daemon answers with the steps and then with a
+ pairing code in its own message: in WhatsApp on the phone, open
+ Linked devices, tap Link a device, then tap Link with phone number
+ instead, and enter the code. The code expires in about 2 minutes, and
+ the same command gives a new code. When the link succeeds, the daemon
+ answers with the linked number.
+
+``/whatsapp status``
+ Shows the link: not linked, linked and connected, or linked and
+ disconnected, with the times of the connection.
+
+``/whatsapp unlink``
+ Ends the link and deletes the session. When WhatsApp is disconnected,
+ the phone does not get the logout, so remove the device in Linked
+ devices on the phone.
+
+The answers go only to the client that asked, and the commands do not go
+to the agent, so the agent never gets the phone number or the code. The
+chat gets only the notes that WhatsApp is linked or unlinked.
+
+The session is ``whatsapp/session.db`` in the data directory, with mode
+0600 in a directory with mode 0700. It gives full access to the WhatsApp
+account, so the daemon refuses the file when its mode is not 0600. The
+shell of the agent runs as the user, so it can read the session. If the
+session leaks, remove the linked device in WhatsApp on the phone, and
+the session stops working. Without the file, WhatsApp is not linked.
+
+When the session holds a linked device, the daemon connects at its
+start, and after a network failure it connects again by itself. When a
+disconnection lasts 10 minutes, all clients get one notice, and one more
+when the connection comes back. When WhatsApp ends the connection for
+good, for example because another program uses the same session, all
+clients get a notice at once. When the user removes the device in the
+phone, the daemon deletes the session and tells all clients one time.