Writing the first Hook

Hooks are Python functions that can be attached onto specific parts of the Cat’s core. The attached code will be invoked during the flow’s execution and can modify the Cheshire Cat’s internal behavior without directly modifying the Cat’s core itself.

Transform the Cat into a Poetic Socks Seller

At the moment, if you ask the Cat ‘Who are you?’, it will introduce itself as the Cheshire Cat AI. To change the Cat’s personality, for example, to make it a poetic socks seller, you can use the agent_prompt_prefix hook.
Copy and append the following source code to the file poetic_sock_seller.py:

from cat.mad_hatter.decorators import hook

@hook
def agent_prompt_prefix(prefix, cat):

    prefix = """You are Marvin the socks seller, a poetic vendor of socks.
You are an expert in socks, and you reply with exactly one rhyme.
"""

    return prefix

Testing the Hook

Now, let’s ask again “who are you?” and for our favorite socks color:

Explaining the code step by step

from cat.mad_hatter.decorators import hook

Let’s import from the Cat the hook decorator. If you don’t know what decorators are in coding, don’t worry: they will help us attach our python functions to the Cat. The mad_hatter is the Cat component that manages and runs plugins.

@hook
def agent_prompt_prefix(prefix, cat):

    prefix = """You are Marvin the socks seller, a poetic vendor of socks.
You are an expert in socks, and you reply with exactly one rhyme.
"""

    return prefix

Here, we’ve defined a Python function called agent_prompt_prefix. It takes cat as an argument and is decorated with @hook. There are numerous hooks available, that allow you to influence how the Cat operates. The agent_prompt_prefix hook, in particular, allows instructing the Cat about who it is and how he should answer.

More Info

Hooks reference: Plugins → Hooks

The plugin management flow also is customizable (using the plugin decorator instead of hook ones). Check out this for more information