Git Worktrees Need Runtime Isolation: Port, Database, Cache, and Secret Collisions Break Parallel AI Agent Development

Penligent·medium signal

Penligent research demonstrates that git worktrees alone are insufficient for parallel AI agent execution. While Claude Code and Windsurf support worktree-based branch isolation, they don't prevent runtime collisions: shared ports, databases, caches, test state, and environment variables leak across parallel sessions. Environment variable leakage is the biggest blind spot — even properly isolated sandboxes can exfiltrate secrets unless you explicitly scrub env vars or restrict network egress. Defense-in-depth required: isolation + resource limits + network controls + permission scoping.