Updates docs, removes custom handler from source and config

docs/source/contributors/index.md

@@ -2,7 +2,8 @@
 
 This page is intended for people interested in building new or modified functionality for Jupyter AI.
 
-If you would like to build applications that enhance Jupyter AI, please see the {doc}`developer's guide </developers/index>`.
+If you would like to build applications that enhance Jupyter AI,
+please see the {doc}`developer's guide </developers/index>`.
 
 ## Design principles
 

docs/source/developers/index.md

@@ -120,3 +120,43 @@ class MyProvider(BaseProvider, FakeListLLM):
 ```
 
 Please note that this will only work with Jupyter AI magics (the `%ai` and `%%ai` magic commands). Custom prompt templates are not used in the chat interface yet.
+
+## Custom slash commands in the chat UI
+
+You can add a custom slash command to the chat interface by
+creating a new class that inherits from `BaseChatHandler`. Set
+its `id`, `name`, `help` message for display in the user interface,
+and `routing_type`. Each custom slash command must have a unique
+slash command. Slash commands can only contain ASCII letters, numerals,
+and underscores. Each slash command must be unique; custom slash
+commands cannot replace built-in slash commands.
+
+Add your custom handler in Python code:
+
+```python
+from jupyter_ai.base import BaseChatHandler, SlashCommandRoutingType
+
+class CustomChatHandler(BaseChatHandler):
+    id = "custom"
+    name = "Custom"
+    help = "A chat handler that does something custom"
+    routing_type = SlashCommandRoutingType(slash_id="custom")
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    async def _process_message(self, message: HumanChatMessage):
+        # Put your custom logic here
+```
+
+Jupyter AI uses entry points to support custom slash commands. 
+In the `pyproject.toml` file, add your custom handler to the
+`[project.entry-points."jupyter_ai.chat_handlers"]` section:
+
+```
+[project.entry-points."jupyter_ai.chat_handlers"]
+custom = "custom_package:chat_handlers.CustomChatHandler"
+```
+
+Then, install your package so that Jupyter AI adds custom chat handlers
+to the existing chat handlers.

packages/jupyter-ai/jupyter_ai/chat_handlers/__init__.py

@@ -1,7 +1,6 @@
 from .ask import AskChatHandler
 from .base import BaseChatHandler, SlashCommandRoutingType
 from .clear import ClearChatHandler
-from .custom import CustomChatHandler
 from .default import DefaultChatHandler
 from .generate import GenerateChatHandler
 from .help import HelpChatHandler

packages/jupyter-ai/pyproject.toml

@@ -39,9 +39,6 @@ dependencies = [
 
 dynamic = ["version", "description", "authors", "urls", "keywords"]
 
-[project.entry-points."jupyter_ai.chat_handlers"]
-custom = "jupyter_ai:chat_handlers.CustomChatHandler"
-
 [project.entry-points."jupyter_ai.default_tasks"]
 core_default_tasks = "jupyter_ai:tasks"