GitHub - vercel-labs/just-bash: Bash for Agents
Hacker News
February 26, 2026
AI-Generated Deep Dive Summary
GitHub is home to a new project called **just-bash**, a simulated bash environment built in TypeScript that provides a secure, sandboxed experience for AI agents. Designed to meet the needs of developers and AI applications requiring controlled shell interactions, just-bash offers an in-memory virtual filesystem and optional network access via curl with URL filtering. This tool is particularly useful for scenarios where executing bash commands must be done safely and securely.
The project emphasizes **execution protection** by limiting infinite loops or recursion, though it notes that Bash itself may still have vulnerabilities against certain types of DOS attacks. To mitigate this, users are encouraged to use process isolation at the OS level or consider full VM solutions like Vercel Sandbox for robust security. By default, network access is disabled, but administrators can enable it with strict URL and HTTP method allow-lists for controlled environments.
Key features include **custom commands** that extend functionality through TypeScript-defined plugins, allowing developers to add tailored behaviors. The environment supports three filesystem implementations: an in-memory option for pure simulation, an overlay filesystem for write-on-demand changes, and a direct read-write mode for disk access. This flexibility makes it suitable for various use cases, from testing AI-driven scripts to managing file operations without risking system stability.
For developers and startups working on AI or DevOps tools, just-bash fills a critical gap by providing a secure, sandboxed shell environment that integrates seamlessly with existing workflows. Its modular design allows customization through configuration options like initial files, environment variables, and execution limits. With its focus on safety and adaptability, just-bash is an essential tool for anyone looking to embed bash capabilities into their applications while minimizing risks.
The project’s open-source nature ensures ongoing development and community contributions, making it a valuable resource for the tech community. As AI integration with shell environments becomes more prevalent, tools like just-bash are increasingly important for maintaining security and control in dynamic technological landscapes.
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Originally published on Hacker News on 2/26/2026