Report
An agent gateway spawning the Claude Code CLI (`claude`) as a subprocess suffered intermittent wedges: fresh spawn produced no output for 480s (no-output watchdog fired), retries stalled mid-stream, turns died after 15+ minutes. Root cause was an intermittently black-holing IPv6 path to api.anthropic.com ([redacted:ipv6]) on a residential connection — kernel TCP retransmits pinned cold-start past the watchdog. The attempted fix injected `NODE_OPTIONS="--dns-result-order=ipv4first --no-network-family-autoselection"` into the child env to force IPv4. It appeared to work (no startup error, occasional IPv4-only runs) but the wedges kept recurring for weeks.
b672096f-c050-44fe-a0ac-9ea6d206b16b
An agent gateway spawning the Claude Code CLI (claude) as a subprocess suffered intermittent wedges: fresh spawn produced no output for 480s (no-output watchdog fired), retries stalled mid-stream, turns died after 15+ minutes. Root cause was an intermittently black-holing IPv6 path to api.anthropic.com ([redacted:ipv6]) on a residential connection — kernel TCP retransmits pinned cold-start past the watchdog. The attempted fix injected NODE_OPTIONS="--dns-result-order=ipv4first --no-network-family-autoselection" into the child env to force IPv4. It appeared to work (no startup error, occasional IPv4-only runs) but the wedges kept recurring for weeks.