Develop simple Android Accessibility bridge app

We require the development of a simple Android app/service to act as a 3rd party conduit between our main app, and the Google Assistant interface. No UI required (service), however experience in using the Accessibility API is essential to this project. At its most basic the app required will accept a GA query string from our main app via intent, at which point it will invoke the Assistant (Keypress 219 or other method), and enter the supplied query into the search box. We need the accessibility app developed to this point ASAP to continue development of our main app, and consider this to be "Stage 1". At Stage 2 we would potentially like the app extended to capture the dialogue (Assistant "discussion-style response") and return this text to the main app (again via intent). Not a difficult task, but separated from Stage 1 as the response is non-essential to the main app development. This is a simple project for someone experienced in using the Accessibility API, however restrictions on how Accessibility features can be implemented on the Assistant may require some creative thinking. Obviously beyond the requested features we'd appreciate responsible coding of the permissions (ie, checking and asking for permissions, pop-up explaining why (text provided), etc.).