Windows: runner heartbeat spawns node.exe with a visible flashing console window every ~20-30s #172

Summary

On Windows, the machine runner (ama-runner.exe) spawns a short-lived node.exe child process roughly every 20–30 seconds (runtime heartbeat / availability probe). Each spawn allocates a new console window (conhost.exe), so the user sees a cmd/console window flash on screen every ~20–30 seconds for as long as the runner daemon is running. Functionality is unaffected; it is a constant visual disturbance.

Command

ak start

(daemon running normally afterwards; the flashing starts as soon as the runner is online)

Expected

Background child processes spawned by the runner are invisible — no console window appears. This is what ak itself already does for the daemon process (the CLI passes windowsHide: true when spawning the runner in packages/cli/src/commands/start.ts).

Actual

Every ~20–30s a console window flashes and disappears. Process monitoring shows:

node.exe   (parent = ama-runner.exe, the runner daemon PID)
└─ conhost.exe   ← the visible flashing console window

Captured twice within a 45-second observation window; the node.exe child lives for well under a second (its command line could not even be sampled via WMI before exit). Timing matches the runner's runtime heartbeat, which probes the installed runtime CLIs (claude-code, codex, copilot) — these are Node.js programs on Windows, so each probe launches node.exe.

For comparison, Docker Desktop performs similar periodic child-process probes (docker stats) on the same machine with no visible window, because it creates its children with a hidden console.

Likely cause / suggested fix

ama-runner (Go) appears to spawn child processes without suppressing console allocation on Windows. Setting syscall.SysProcAttr{HideWindow: true, CreationFlags: windows.CREATE_NO_WINDOW} on the exec.Cmd used for runtime probes (and any other periodic child spawns) should fix it. macOS/Linux are unaffected, which is probably why this went unnoticed.

Context

• ak version: 1.15.0
• ama-runner: 0.7.0 (3f1b968, built 2026-07-18T04:35:57Z)
• OS: Windows 11 Home 10.0.26200
• Runtime: claude (installed via npm, claude.cmd shim → node)
• Auth type: machine
• Providers reported by runner: codex, claude-code, copilot

Reproduction

1. On Windows 11, install agent-kanban globally via npm (Node runtimes such as Claude Code installed via npm as well).
2. ak start and complete AMA device login; runner goes online.
3. Watch the screen (or monitor process creation): a node.exe + conhost.exe pair is created by ama-runner.exe every ~20–30s, flashing a console window each time.