cmux-backend — Claude Code skill: what it does, how to install
Rules for cmux backend TypeScript and Cloud VM work, covering Effect, Postgres, migrations, provider integrations, and auth pricing gates.
npx skills add manaflow-ai/cmux --skill cmux-backend -a claude-codeWhat cmux-backend does
cmux-backend guides backend changes in cmux. It sets when to use Effect in web/app/api/**, web/services/**, and scripts that handle providers, databases, auth, limits, retries, timeouts, or telemetry. Next.js route handlers should parse the request, run one Effect program, and turn typed failures into HTTP responses.
The skill also covers Cloud VM lifecycle state, active-VM limits, idempotency, usage events, and Stack Auth payment checks. It refers to DATABASE_URL, CMUX_DB_DRIVER=url, the migration command bun run cloud-vm:migrate -- staging followed by -- production, and provider secrets from ~/.secrets/cmux.env. Run migrations as a separate operation, not from route startup or a Vercel build. Local development keeps the Docker Postgres path used by bun dev.
What it helps with
- separate Next.js route parsing from Effect logic
- model Cloud VM lifecycle state in Postgres
- run staging and production migrations
- apply Stack Auth pricing gates to VM creation
- load provider secrets for Cloud VM image builds
Example prompts for the agent
- Apply
cmux-backendto a new route underweb/app/apiand move its error handling into Effect. - Review the Cloud VM image build script and load provider secrets from
~/.secrets/cmux.env, includingFREESTYLE_API_KEY. - Prepare the Cloud VM database migration and run it for
staging, then forproduction.
How to install cmux-backend
1Skills CLI (Vercel)
npx skills add manaflow-ai/cmux --skill cmux-backend -a claude-code2Manually: put the files in place
~/.claude/skills/cmux-backend/SKILL.mdCopy the whole skill folder; for one project use .claude/skills/cmux-backend/
1Skills CLI (Vercel)
npx skills add manaflow-ai/cmux --skill cmux-backend -a codex2Manually: put the files in place
.agents/skills/cmux-backend/SKILL.mdFor all projects use ~/.agents/skills/
1Skills CLI (Vercel)
npx skills add manaflow-ai/cmux --skill cmux-backend -a cursor2Manually: put the files in place
.cursor/skills/cmux-backend/SKILL.mdCursor also reads .agents/skills/ and .claude/skills/
1GitHub CLI
gh skill install manaflow-ai/cmux cmux-backend2Manually: put the files in place
.github/skills/cmux-backend/SKILL.md1Skills CLI (Vercel)
npx skills add manaflow-ai/cmux --skill cmux-backend -a gemini-cli2Platform CLI
gemini skills install https://github.com/manaflow-ai/cmux --path skills/cmux-backendManually: put the files in place
.devin/skills/cmux-backend/SKILL.mdThe legacy .windsurf/skills/ path still works
Skills CLI (Vercel)
npx skills add manaflow-ai/cmux --skill cmux-backend -a opencodeClaude.ai
Zip the folder and upload it in Settings → Capabilities → Skills
Step by step, with commands for each platform: How to install skills in Claude Code: five ways
Questions about cmux-backend
How do I install cmux-backend in Claude Code?
Run npx skills add manaflow-ai/cmux --skill cmux-backend -a claude-code, then check ~/.claude/skills/cmux-backend/SKILL.md.
What does cmux-backend do?
It sets backend TypeScript rules for Effect, Cloud VM lifecycle work, Postgres, migrations, provider integrations, and Stack Auth pricing checks in cmux.
Which platforms support cmux-backend?
The skill supports Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, and OpenCode.
