Cost.dev (YC W21) – making agents cost-aware and cheaper to call

Cost.dev (YC W21) is a developer tool that makes AI agents cost-aware by providing real-time cost estimates for API calls, helping engineers optimize spending before executing expensive agent workflows. Built by the team behind Infracost, it shifts FinOps left for AI, targeting developers who build and deploy LLM-based agents. It’s interesting because it addresses the growing problem of unpredictable AI costs, enabling teams to build cheaper, more efficient agents by surfacing cost data at the point of decision.