We model a document treatment chain as a Markov Decision Process, and use reinforcement learning to allow the agent to learn to construct and continuously improve custom-made chains " on the fly ". We build a platform which enables us to measure the impact on the learning of various models, web services, algorithms, parameters, etc. We apply this in an industrial setting, specifically to an open source document treatment chain which extracts events from massive volumes of web pages and other open-source documents. Our emphasis is on minimising the burden of the human analysts, from whom the agent learns to improve guided by their feedback on the events extracted. For this, we investigate different types of feedback, from numerical feedback, which requires a lot of tuning, to partially and even fully qualitative feedback, which is much more intuitive, and demands little to no user calibration. We carry out experiments, first with numerical feedback, then demonstrate that intuitive feedback still allows the agent to learn effectively.