Refact – Open-Source AI Agent, Code Generator & Chat for JavaScript, Python, TypeScript, Java, PHP, Go, and more.Extension40/100 via “in-ide chat interface with @-command context attachment”
Refact.ai is the #1 free open-source AI Agent on the SWE-bench verified leaderboard. It autonomously handles software engineering tasks end to end. It understands large and complex codebases, adapts to your workflow, and connects with the tools developers actually use (including MCP). It tracks your
Unique: Implements explicit @-command syntax for context attachment, allowing developers to control exactly what information is sent to the LLM, preventing accidental exposure of sensitive code. This differs from Copilot Chat, which automatically infers context from the editor state without explicit user control.
vs others: More transparent and controllable than Copilot Chat because developers explicitly specify context via @-commands, reducing risk of unintended code exposure while enabling precise multi-source reasoning (code + web + definitions simultaneously).