@netrodev/hxf-env

Remote execution environments for HowToFix Durable: an agent's tools run on another machine, usually over SSH, while the Durable worker, its storage and credentials stay local.

• hxf-env (daemon/): a small Rust program that runs on the remote machine. It speaks a framed protocol on stdin and stdout (docs/protocol.md) and performs file operations and commands there.
• RemoteExecutionEnv: a Durable ExecutionEnv that talks to the daemon through a Connection. Its results match NodeExecutionEnv running on the remote machine; only error messages may differ (docs/semantics.md).

import { acceptHostKey, connectSsh, HostKeyUnknownError, RemoteExecutionEnv, scanHostKey } from "@netrodev/hxf-env";

const target = { host: "gpu-box", knownHostsFile: "/data/ssh/known_hosts", hostKeyAlias: "hxf-env-gpu" };
// Once: show the host's key fingerprint to the owner, who compares it out of band and accepts it.
const { lines, fingerprints } = await scanHostKey(target);
await acceptHostKey(target, lines);

// Detects the remote system, deploys the daemon if missing (named by its SHA-256 and verified before every start),
// and returns a connection that starts it over ssh.
const { connection } = await connectSsh(target);
const env = new RemoteExecutionEnv({ connection, id: "hxf-env:gpu", cwd: "/home/me/project" });

The package ships the daemon for every supported remote system in bin/. ssh runs with BatchMode, strict host-key checking against the application's own known-hosts file under a fixed alias, no forwarding of any kind, no shared connections or configured commands, and without forwarding the local locale. On Windows, detection and deployment go through PowerShell, and the daemon starts through the server's default shell (cmd.exe or PowerShell).

Supported remote systems: Linux, macOS, Android (Termux) and Windows, on x86-64 and arm64. On Windows, string commands run through Git Bash as NodeExecutionEnv runs them there; argv commands run directly.

Development

npm run build:daemon builds the daemon with Cargo; the tests talk to daemon/target/debug/hxf-env over a pipe, or to the binary named by HXF_ENV_DAEMON (CI tests the release builds this way). They run Durable's env conformance suite against RemoteExecutionEnv and compare random operation sequences and Durable's tools against NodeExecutionEnv on the same machine. test/ssh-external.test.ts runs the suite over a real SSH server when HXF_ENV_SSH_HOST is set.