Add ability to define custom agent action and instructions + example

[derekmeegan]

This PR provides an initial POC for a fallback agent with custom actions, such as notifying a Discord server when an action fails with the error details and the agent's plan.

I am not sure if providing individual agent params or instantiating the agent and passing it into the workflow obj is the best route ultimately, but figured this is a good start. In the example workflow.json, I intentionally added the "XXXXXXX" prefix to the selectors, XPath, tag, and text of step 2 to make the action break and trigger the agent to step in. The custom instruction is also necessary for the agent to decide to use the action.

More to come 🚀

[gregpr07]

Have to think for a few minutes if this makes sense. I LOVE the idea behind it but right now it's kinda ugly to do this way.

This would go hard with some proper .cursorrules so that you can just generate workflows with cursor directly inline or sth

[derekmeegan]

Yeah, I agree that the piecemeal approach for the agent inputs is not ideal. Are you imagining the user could define their own fallback agent directly? Or maybe a WorkflowAgent class is needed that would wrap the user's custom instructions with the fallback prompt template and set other parameters.