In a bid to defend its market share against rapidly advancing, lower-cost Chinese rivals, US artificial intelligence firm OpenAI has launched an aggressive price war, slashing prices for its latest GPT-5.6 model line-up by up to 80 per cent. In a post on social media platform X on Thursday, OpenAI CEO Sam Altman announced an 80 per cent drop in developer pricing for its lightweight GPT-5.6 Luna model, bringing application programming interface (API) costs down to US$0.20 per million input tokens...