The document discusses different design thinking tools used in a co-innovation program for a large banking customer. It summarizes the tools of assumption testing, brainstorming, and storytelling. For assumption testing, ideas from brainstorming sessions were evaluated by having idea owners state assumptions and plans to validate them. This helped improve ideas and catch flaws earlier. Brainstorming sessions encouraged novel ideas within set objectives, and maintained a positive tone. Storytelling used customer pain point stories to engage technical staff lacking banking experience and elicit many innovative ideas to improve the customer experience.