@kortix/agent-tunnel

@kortix/agent-tunnel connects a local computer to Kortix through an authenticated reverse tunnel.

Connect once

Run the command shown in a Computer Tunnel connector profile. Then approve the device code in your browser:

npx --yes @kortix/agent-tunnel@latest connect \
  --api-url https://api.kortix.com/v1/tunnel

After approval, the interactive flow asks whether it should install a persistent background service. The default answer is yes.

Run in the background

Install the operating-system background service during connection:

npx --yes @kortix/agent-tunnel@latest connect \
  --daemon \
  --api-url https://api.kortix.com/v1/tunnel

The service uses LaunchAgent on macOS, a user systemd service on Linux, and Task Scheduler on Windows. It starts at login and restarts after failures. It does not change the computer's sleep settings.

Manage the background service

npx --yes @kortix/agent-tunnel@latest service-status
npx --yes @kortix/agent-tunnel@latest logs
npx --yes @kortix/agent-tunnel@latest restart
npx --yes @kortix/agent-tunnel@latest stop
npx --yes @kortix/agent-tunnel@latest uninstall-service

Credentials are stored in ~/.agent-tunnel/config.json. Agent Tunnel requires the file to be regular, owned by the current user, and mode 0600 on POSIX. Protect the operating-system account because this setup token can authenticate the machine until you rotate or delete the connection.

Remote API URLs must use HTTPS. Plain HTTP is accepted only for localhost, 127.0.0.1, and ::1 development endpoints.

Permission boundaries

Kortix checks connector profile assignment, connector grants, connector tool policy, and the machine permission before relaying an operation. The local agent then checks the machine permission again.

The local config is the maximum boundary. A server grant cannot widen configured filesystem paths, blocked paths, shell commands, timeouts, file sizes, or desktop features. An empty permission scope is unrestricted inside those local ceilings. Use scoped permissions and short expiries for sensitive machines.

Computer Use driver

Agent Tunnel never downloads or executes a desktop driver. Install cua-driver locally before enabling Computer Use. The tunnel uses an existing binary from CUA_DRIVER_BIN, ~/.local/bin, /usr/local/bin, or /opt/homebrew/bin. Treat that binary as trusted local code. Agent Tunnel does not verify or update it.

Transfer a binary file without copying base64

Run the client where the source file exists. Set TUNNEL_API_URL, TUNNEL_TOKEN, and TUNNEL_ID for the target connection, then run:

agent-tunnel-cli fs_upload '{"source":"/tmp/report.xlsx","path":"/Users/me/Desktop/report.xlsx"}'

fs_upload reads bytes from source, computes SHA-256, and sends the bytes programmatically over the authenticated tunnel. It requires filesystem write permission. A pending approval returns success: false and exit code 1; retry only after approval. The command accepts regular files up to 3 MiB, which leaves room under the relay's 5 MiB message limit after base64 encoding.

The connected agent checks the supplied sha256 before modifying the destination. It reads the file after writing and returns its persisted sha256 and size. The CLI succeeds only when both match the source. An older agent without checksum support causes verification to fail; the file may already exist. Update the agent before retrying.

For raw fs.write, sha256 is optional for compatibility. Supply it for binary content. Never copy an opaque base64 payload from model context. Generate the file on the destination when a programmatic transfer is unavailable. A matching hash proves byte integrity, not format validity: validate XLSX/ZIP structure and workbook contents at the source. File size and magic bytes are insufficient. Do not use public file-host relays for this workflow.