Replit has introduced Agent 3, its latest autonomous software agent built to extend the use of AI in programming and workflow automation. Unlike earlier coding assistants that provide small pieces of help through autocomplete or single-step code generation, Agent 3 is designed to carry out tasks over an extended period of time. The system can operate for up to 200 minutes continuously, giving it the capacity to plan, write, test, and refine entire software components without requiring constant user intervention.
A key technical feature of Agent 3 is its self-testing and debugging loop. Once it generates code, the agent executes it, identifies errors, applies fixes, and reruns the code until it passes tests or meets the specified requirements. This cycle is intended to reduce the need for developers to manually step in during the build process. Replit reports that in internal evaluations, this system performed up to three times faster and at one-tenth of the cost compared with its earlier computer use models.
Another capability of Agent 3 is its ability to spawn new agents. Users can describe a desired workflow in natural language, and Agent 3 will generate a specialized agent capable of handling it. These generated agents can integrate with services such as Slack, email, and Telegram, enabling applications like automated status updates, customer support responses, or internal reporting tools. This approach shifts the role of the agent from a single assistant into a platform for creating domain-specific automations.
In comparison with existing products, Agent 3 marks a departure from tools such as GitHub Copilot or OpenAI’s code interpreter. Copilot focuses on inline code completion within integrated development environments, offering developers suggestions as they type, but it does not independently execute or validate code. OpenAI’s interpreter can interact with files and perform computations, but they typically run in shorter sessions and require closer user guidance. By contrast, Agent 3’s longer runtime and embedded self-debugging loop allow it to function more like a semi-autonomous developer than a real-time assistant.
Agent 3 also introduces a step toward workflow automation. Where traditional code assistants concentrate on programming tasks, Agent 3 can handle multi-application scenarios, such as connecting a database to a notification system or automating scheduled tasks across communication channels. This positions the tool closer to general-purpose automation platforms like Zapier or n8n, but with the added advantage of generating and adapting the underlying code.
Developers are particularly impressed by Agent 3’s ability to autonomously handle complex tasks for extended periods, with many noting its potential to revolutionize software development by reducing the need for constant human oversight, but also questioning the testing phase in software development. Software developer Himanshu Kumar shared:
Intriguing. Autonomy is key, but robust testing remains crucial for reliable software. Is 10x enough?
Meanwhile entrepreneur Shawn Chauhan commented:
Agents evolving fast, but testing remains the real bottleneck.
Replit announced that for developers and organizations already working on Replit, the integration is immediate. Agent 3 can be used within the platform to build prototypes, extend projects, or create custom automation agents. Its release reflects a broader trend toward embedding AI not just in code completion, but in the full cycle of planning, execution, and deployment.