論文アブストラクト：In addition to simple form filling, there is an increasing need for crowdsourcing workers to perform freeform interactions directly on content in microtask crowdsourcing (e.g. proofreading articles or specifying object boundary in an image). Such microtasks are often organized within well-designed workflows to optimize task quality and workload distribution. However, designing and implementing the interface and workflow for such microtasks is challenging because it typically requires programming knowledge and tedious manual effort. We present ReTool, a web-based tool for requesters to design and publish interactive microtasks and workflows by demonstrating the microtasks for text and image content. We evaluated ReTool against a task-design tool from a popular crowdsourcing platform and showed the advantages of ReTool over the existing approach.