Portless Integration

Named .localhost URLs for local development. Replaces localhost:3000 with https://myapp.localhost.

Full CLI reference: Load Read("${CLAUDE_SKILL_DIR}/references/upstream.md") for complete command docs.

When to Use

• Starting a dev server that agents or browser tests will target
• Running multiple services locally (API + frontend + docs)
• Working in git worktrees (branch-named subdomains)
• Local OAuth flows (stable callback URLs)
• Connecting emulate API mocks to named URLs

Quick Start

# Instead of: npm run dev (random port)
portless run npm run dev
# → https://myapp.localhost (stable, named, HTTPS)

# Multi-service
portless run --name api npm run dev:api
portless run --name web npm run dev:web
# → https://api.localhost, https://web.localhost

Framework-Specific Setup

Load Read("${CLAUDE_SKILL_DIR}/references/framework-integration.md") for full framework recipes.

Most frameworks (Next.js, Vite, Express) work with portless run <cmd>. Some need explicit flags:

Framework	Auto-detected?	Extra flags needed
Next.js	Yes	None
Vite / Astro	Yes	None
Express / Fastify / Hono	Yes	None (reads PORT env var)
Ruby on Rails	Yes	None
FastAPI / uvicorn	No	--port $PORT --host $HOST
Django	No	$HOST:$PORT positional arg

Why .localhost?

Feature	.localhost (RFC 6761)	127.0.0.1:PORT	/etc/hosts hack
No /etc/hosts editing	Yes	Yes	No
HTTPS with valid cert	Yes	No	Manual
Wildcard subdomains	Yes	No	No
Works in all browsers	Yes	Yes	Varies
Cookie isolation per service	Yes	No	Yes
No port conflicts	Yes	No	Yes

Key Environment Variables

When portless runs your command, it injects:

Variable	Value	Use in agents
PORT	Assigned ephemeral port (4000-4999)	Internal only
HOST	127.0.0.1	Internal only
PORTLESS_URL	https://myapp.localhost	Use this in agent prompts

OrchestKit Integration Patterns

1. Agent-Accessible Dev Server

# Start with portless, then agents can target PORTLESS_URL
portless run npm run dev

# In ork:expect or agent-browser:
agent-browser open $PORTLESS_URL

2. Emulate + Portless (Named API Mocks)

# Register emulate ports as named aliases
portless alias github-api 4001
portless alias vercel-api 4000
portless alias google-api 4002

# Now agents can target:
#   https://github-api.localhost — GitHub emulator
#   https://vercel-api.localhost — Vercel emulator

3. Git Worktree Dev

# In worktree for feature/auth-flow:
portless run npm run dev
# → https://auth-flow.myapp.localhost (auto branch prefix)

4. Bypass in CI

# Disable portless in CI — direct port access
PORTLESS=0 npm run dev

Anti-Patterns

Don't	Do Instead
Hardcode localhost:3000 in tests	Use PORTLESS_URL or process.env.PORTLESS_URL
Run portless in CI	Set PORTLESS=0 in CI environments
Use numeric ports in AGENTS.md	Document the portless URL

References

File	Content
references/upstream.md	Full portless CLI reference (synced from Vercel)
references/upstream-oauth.md	OAuth callback patterns with stable URLs
references/framework-integration.md	Framework recipes (FastAPI, Django, Docker, gotchas)
checklists/new-project-setup.md	Step-by-step: add portless to a new project