cmux-backend
Backend TypeScript and Cloud VM development rules for cmux. Use when editing web/app/api, web/services, backend scripts, Cloud VM lifecycle, provider integrations, Postgres, Stack Auth pricing gates, migrations, or provider image build scripts.
git clone --depth 1 https://github.com/manaflow-ai/cmux /tmp/cmux-backend && cp -r /tmp/cmux-backend/skills/cmux-backend ~/.claude/skills/cmux-backendSKILL.md
# cmux Backend ## Core rules - Default backend TypeScript to Effect under `web/app/api/**`, `web/services/**`, and backend scripts touching providers, databases, auth, rate limits, retries, timeouts, or telemetry. - Keep Next route handlers thin: parse the request, run one Effect program at the boundary, map typed errors to HTTP responses, treat unexpected defects separately. - Plain TypeScript is for trivial data shapes, constants, config files, frontend React, and small glue where Effect would add ceremony without improving failure handling. - Cloud VM backend logic stays in Vercel route handlers and Effect services backed by Postgres. Do not reintroduce Rivet or a raw actor protocol unless a later architecture doc explicitly changes the control plane. - Postgres is the source of truth for VM lifecycle, active VM limits, idempotency, and usage events. - Production and staging Cloud VM Postgres use the Vercel Marketplace AWS Aurora PostgreSQL OIDC/RDS IAM path, with runtime env `CMUX_DB_DRIVER=aws-rds-iam`, `AWS_ROLE_ARN`, `AWS_REGION`, `PGHOST`, `PGPORT`, `PGUSER`, `PGDATABASE`. - Run production/staging migrations with `bun db:migrate:aws-rds-iam`; never from Vercel build or route startup. Local dev keeps the `CMUX_PORT`-derived Docker Postgres path from `bun dev`. - Cloud VM create pricing gates use Stack Auth team payment items when enabled. ## Secrets Cloud VM build, test, and local dev scripts read provider secrets from `~/.secrets/cmux.env`: `E2B_API_KEY`, `FREESTYLE_API_KEY`, and the R2 upload vars `web/scripts/build-cloud-vm-images.ts` needs when creating Freestyle snapshots. ```bash set -a source ~/.secrets/cmux.env set +a ``` `~/.secrets/cmuxterm-dev.env` holds local Stack/web env and not the provider build keys. `bun dev` sources `~/.secrets/cmux.env` first when present, then `~/.secrets/cmuxterm-dev.env`, so cmuxterm-specific Stack settings override broader cmux secrets. The web dev loader still accepts the legacy `~/.secret/cmuxterm.env` and `~/.secrets/cmuxterm.env` paths while machines migrate. ## Detailed references - [references/effect-boundaries.md](references/effect-boundaries.md): route handlers, services, typed errors, retries, dependency injection. - [references/cloud-vm-control-plane.md](references/cloud-vm-control-plane.md): VM lifecycle, migrations, Postgres, provider idempotency, pricing gates.
cmux package architecture, refactor layering, dependency inversion, file organization, DocC documentation, package design discipline, testability, and Swift 6 concurrency rules. Use before adding or meaningfully rewriting Swift files, Swift packages, coordinators, services, repositories, or public package APIs.
Stripe checkout, pricing, subscription, Pro plan, webhook, and entitlement runbook for cmux billing work. Use when editing or debugging billing, pricing, Stripe Checkout, subscription recording, Pro plan status, webhooks, entitlement metadata, or pricing dev/prod tooling.
End-user browser automation with cmux. Use when you need to open sites, interact with pages, wait for state changes, and extract data from cmux browser surfaces.
Route work to cmux Cloud machines (persistent cloud VMs) from the CLI — `cmux vm route`/`run`/`agent` pick a machine for you; `vm tree` / `surface ls` show the surface catalog (This Mac and every machine: terminals, VNC screens, browsers) and `vm open` / `surface open` put any of them in a pane; plus create, exec, push/pull, ports, checkpoints, forks. Use when an agent should run builds, tests, servers, desktop/browser tasks, or another agent on a cloud machine instead of the local Mac, or when the user says "cloud machine", "cloud VM", "run it in the cloud", or "cmux vm".
Drive real macOS apps from a cmux agent session via the bundled computer-use engine (accessibility tree + screenshot perception, click/type/scroll/drag, branded agent cursor). Use when an agent should see and operate GUI apps on the local Mac, when computer-use tools are missing or failing, or when explaining how to grant permissions, brand the cursor, or focus the driving session.
Build a custom cmux sidebar from a plain-language request. Use when the user asks for a custom sidebar, a sidebar that shows their workspaces/tabs/PRs/clock, a vibe-coded sidebar, or anything involving files in ~/.config/cmux/sidebars/. Covers authoring the interpreted SwiftUI-style file, enabling the beta flag, selecting it, and iterating with hot reload.
Customize cmux for an end user. Use when changing cmux.json actions, custom commands, workspace layouts, plus-button behavior, surface tab bar buttons, Command Palette entries, Dock controls, sidebar and app settings, shortcuts, notifications, browser routing, examples-library presets, or Ghostty-backed terminal preferences.