Agent skill · software engineering · aiskillstore
gen-env
Creates, updates, or reviews a project's gen-env command for running multiple isolated instances on localhost. Handles instance identity, port allocation, data isolation, browser state separation, and cleanup.
Why this skill is useful
Adds a comprehensive script for managing isolated Docker instances with dynamic port allocation and environment setup that isn't covered in standard documentation.
What it needs
Requires docker installed locally. About 4k tokens when loaded. Last updated 2026-08-07. 405 stars on the source repository.
What this skill does
gen-env Skill Generate or review a gen-env command that enables running multiple isolated instances of a project on localhost simultaneously (e.g., multiple worktrees, feature branches, or versions). The Problem Without isolation, multiple instances of the same project: Fight for hardcoded ports (3000, 5432, 8080) Share Docker volumes → data corruption Share browser cookies/localStorage → auth confusion Have ambiguous container names → can't tell which is which Risk catastrophic cleanup → docker down -v nukes everything The Solution: Instance Identity Everything flows from a workspace name: Isolation Dimensions 1. Port Isolation Each instance gets unique ports from ephemeral range (49152-65535). 2. Data Isolation Docker Compose project name controls volume naming: Instance A: localnet-mainpostgresdata Instance B: localnet-feature-xpostgresdata No cross-contamination. Independent databases. 3. Network Isolation Separate Docker networks per instance. Containers reference each other by service name without collision. 4. Browser State Isolation Critical: Different ports on localhost still share cookies! Solution: subdomain isolation via .localhost: Chrome/Edge treat .localhost as 127.0.0.1 automatically. No /etc/hosts needed. 5. Auth Isolation Each instance can have its own auth realm/audience, preventing token confusion. 6. Resource Naming Clear prefixes on containers, volumes, Tilt resources, logs → know exactly which instance you're looking at. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills aiskillstore/gen-env