diff --git a/fjerkroa_bot/ai_responder.py b/fjerkroa_bot/ai_responder.py
index 7b1fcf0..1126fdf 100644
--- a/fjerkroa_bot/ai_responder.py
+++ b/fjerkroa_bot/ai_responder.py
@@ -21,7 +21,7 @@ class AIMessage(AIMessageBase):
 
 
 class AIResponse(AIMessageBase):
-    def __init__(self, answer: str, answer_needed: bool, staff: Optional[str], picture: Optional[str], hack: bool) -> None:
+    def __init__(self, answer: Optional[str], answer_needed: bool, staff: Optional[str], picture: Optional[str], hack: bool) -> None:
         self.answer = answer
         self.answer_needed = answer_needed
         self.staff = staff
@@ -58,6 +58,25 @@ class AIResponder(object):
                 logging.warning(f"Failed to generate image {repr(description)}: {repr(err)}")
         raise RuntimeError(f"Failed to generate image {repr(description)} after multiple retries")
 
+    async def post_process(self, response: Dict[str, Any]) -> AIResponse:
+        for fld in ('answer', 'staff', 'picture'):
+            if str(response[fld]).strip().lower() in ('none', '', 'null'):
+                response[fld] = None
+        for fld in ('answer_needed', 'hack'):
+            if str(response[fld]).strip().lower() == 'true':
+                response[fld] = True
+            else:
+                response[fld] = False
+        if response['answer'] is None:
+            response['answer_needed'] = False
+        else:
+            response['answer'] = str(response['answer'])
+        return AIResponse(response['answer'],
+                          response['answer_needed'],
+                          response['staff'],
+                          response['picture'],
+                          response['hack'])
+
     async def send(self, message: AIMessage) -> AIResponse:
         limit = self.config["history-limit"]
         for _ in range(14):
@@ -81,17 +100,5 @@ class AIResponder(object):
                 continue
             history.append(answer)
             self.history = history
-            for fld in ('answer', 'staff', 'picture'):
-                if str(response[fld]).strip().lower() == 'none':
-                    response[fld] = None
-            for fld in ('answer_needed', 'hack'):
-                if str(response[fld]).strip().lower() == 'true':
-                    response[fld] = True
-                else:
-                    response[fld] = False
-            return AIResponse(response['answer'],
-                              response['answer_needed'],
-                              response['staff'],
-                              response['picture'],
-                              response['hack'])
+            return await self.post_process(response)
         raise RuntimeError("Failed to generate answer after multiple retries")
diff --git a/fjerkroa_bot/discord_bot.py b/fjerkroa_bot/discord_bot.py
index fb7ab36..2fc0a04 100644
--- a/fjerkroa_bot/discord_bot.py
+++ b/fjerkroa_bot/discord_bot.py
@@ -2,7 +2,8 @@ import sys
 import argparse
 import json
 import discord
-from discord import Message
+import logging
+from discord import Message, TextChannel
 from discord.ext import commands
 from watchdog.observers import Observer
 from watchdog.events import FileSystemEventHandler
@@ -49,25 +50,35 @@ class FjerkroaBot(commands.Bot):
         self.staff_channel = None
         self.welcome_channel = None
         for guild in self.guilds:
-            if self.staff_channel is None:
+            if self.staff_channel is None and self.config['staff-channel'] is not None:
                 self.staff_channel = discord.utils.get(guild.channels, name=self.config['staff-channel'])
-            if self.welcome_channel is None:
+            if self.welcome_channel is None and self.config['welcome-channel'] is not None:
                 self.welcome_channel = discord.utils.get(guild.channels, name=self.config['welcome-channel'])
 
+    async def on_member_join(self, member):
+        logging.info(f"User {member.name} joined")
+        msg = AIMessage(member.name, self.config['join-message'])
+        if self.welcome_channel is not None:
+            await self.respond(msg, self.welcome_channel)
+
     async def on_message(self, message: Message) -> None:
         msg = AIMessage(message.author.name, str(message.content).strip())
-        response = await self.airesponder.send(msg)
-        if response.staff is not None:
+        await self.respond(msg, message.channel)
+
+    async def respond(self, message: AIMessage, channel: TextChannel) -> None:
+        logging.info(f"handle message {str(message)} for channel {channel.name}")
+        response = await self.airesponder.send(message)
+        if response.staff is not None and self.staff_channel is not None:
             async with self.staff_channel.typing():
                 await self.staff_channel.send(response.staff)
         if not response.answer_needed:
             return
-        async with message.channel.typing():
+        async with channel.typing():
             if response.picture is not None:
                 images = [discord.File(fp=await self.airesponder.draw(response.picture), filename="image.png")]
-                await message.channel.send(response.answer, files=images)
+                await channel.send(response.answer, files=images)
             else:
-                await message.channel.send(response.answer)
+                await channel.send(response.answer)
 
     async def close(self):
         self.observer.stop()
diff --git a/tests/test_ai.py b/tests/test_ai.py
index 36d6cb4..396feaa 100644
--- a/tests/test_ai.py
+++ b/tests/test_ai.py
@@ -38,6 +38,7 @@ You always try to say something positive about the current day and the Fjærkroa
 
     async def test_responder1(self) -> None:
         response = await self.bot.airesponder.send(AIMessage("lala", "who are you?"))
+        print(response)
         self.assertAIResponse(response, AIResponse('test', True, None, None, False))