Confirmed.

${GBRAIN}

resolves to the gbrain script whose shebang is

#!/usr/bin/env bun

, but launchd's env has no

~/.bun/bin

on PATH, so

env bun

fails. The clean fix: invoke gbrain explicitly through the absolute

bun

binary in the execSync call, so it never relies on the shebang/PATH. This is the exact workaround pattern already documented in machine-setup.md for MCP. Let me make the minimal edit.