Replit Agent 3 is an autonomous "vibe coding" agent that scaffolds, builds, tests, debugs, and deploys applications inside Replit with minimal human intervention. It provides extended session runtimes (advertised as 200 minutes) and higher autonomy (marketed as "10x more autonomous") to execute multi-step development workflows, run full test suites, and apply fixes automatically. Agent 3 integrates with third-party tools such as Slack and Notion for notifications, briefs and collaboration, and uses model-driven UI navigation and evaluation (e.g., integrations leveraging Claude 3.5 Sonnet’s computer-use capabilities) to interact with and validate running apps. It also supports standardized agent configuration workflows (AGENT.md symbolic linking) and leverages Replit’s visual planner and integrated hosting to streamline prototyping-to-deploy workflows.