@freestyle-sh/fdev-cmux

Small SDK and fdev provider facade for opening workspaces in local cmux.

import { createCmuxClient } from "@freestyle-sh/fdev-cmux";

const cmux = createCmuxClient();

await cmux.newWorkspace({
  name: "playground",
  command: "echo hello world",
  focus: true,
});

Commands are printed to stderr before execution:

$ cmux new-workspace --name playground --command 'echo hello world' --focus true

cmux new-workspace and cmux ssh are socket commands. With cmux's default socket control mode (cmuxOnly), run fdev from a terminal inside cmux so cmux sets CMUX_SOCKET_PATH and accepts the process.

If you intentionally enable external socket control in cmux, opt in explicitly:

const cmux = createCmuxClient({ allowExternalAutomation: true });

With allowExternalAutomation, the SDK can run open -a cmux and retry a workspace command while cmux starts.

Config-defined operations can request the typed cmux.open host capability through the provider facade:

import { workflow } from "@freestyle-sh/fdev";
import { cmux } from "@freestyle-sh/fdev-cmux";

export default workflow("site", {
  providers: {
    cmux: cmux.provider(),
  },
})
  .sequence("site")
  .operation("open", {
    requiredHostCapabilities: [cmux.capabilities.open],
    run: async ({ providers }) => {
      await providers.cmux.open({
        name: "site",
        ssh: {
          host: "vm-ssh.freestyle.sh",
          username: "vm_123",
          auth: { type: "token", token: "token_123" },
        },
        cwd: "/workspace/site",
        command: "pnpm dev",
        url: "http://localhost:3000",
      });
    },
  });

Local hosts can import @freestyle-sh/fdev-cmux/host to register the trusted cmux.open handler. The fdev CLI registers this handler automatically.