Vercel open-sources durable-harness for crash-proof coding agents

Vercel released durable-harness, an open-source package that keeps coding agent sessions alive through crashes and timeouts. It wraps Pi, OpenCode, fx, Claude Code and Codex without modifying them, logging each step to a durable log. The Apache-2.0 package is version 0.0.x and runs on Vercel Functions with Queues, Node.js 22+ with Postgres, or locally.

• Adapters cover 5 harnesses: Pi, OpenCode, fx, Claude Code, Codex
• Completed calls are read from the log and never billed twice
• Claude Code and Codex run only in a Vercel Sandbox
• Virtual workspace holds about 500 files