Whitepaper

Ubahn is a framework for creating chatbot dialogs. Key aspects of Ubahn:

Developers define a conversation structure in a YAML file.
Each conversation consists of named inputs and outputs.
The logic and appearance of inputs and outputs is defined by external applications which use Ubahn.
The framework doesn’t do any NLP or AI, it doesn’t assume which channel is used for communication. It’s purely about creating a structure of a conversation and building specific implementations on top of that structure.
Named after Munich subway system of the same name.

Here’s an example of a conversation:

version: 1

sequence:
  - welcome
  - weather-report

triggers:
  - i-user-welcome

fallback: clarification

outputs:
  welcome:
    expectedInputs:
      i-yes: next
      i-no: bye
    fallback: welcome-clarification

version: 1 defines Ubahn protocol version number. It’s useful if we introduce breaking changes to the format of conversation file.
sequence outlines the structure we want to have in the conversation. It should have a list of named agent outputs, in order of their appearance. Even though the structure is linear, Ubahn supports conditional jumps.
triggers is a list of named inputs that trigger conversation start.
fallback defines the global fallback output which is called when Ubahn doesn’t know which output to call.
outputs defines named agent outputs. Each output may have a dedicated fallback and may expect many inputs. For example in this case:

i-yes: next
i-no: bye

we say that if user input was i-yes, the conversation goes to the next element (weather-report), if the input was i-no, the conversation goes to the bye output.

You may wonder, where do we have those weather-report, bye, i-yes etc.? All of them are just names. You should use Ubahn API to map those names to specific entities with business logic. For example weather-report output may be a rich UI, or a picture—whatever. bye maybe a smile, or a text. i-yes is how your implementation interprets Yes answer, and btw you don’t have to name it i-yes, this is just an example.

Here’s how the above conversation may look like in real life:

ubahn/whitepaper

Whitepaper