Tailscale Docker Debug

Diagnose and fix Tailscale connectivity and DNS issues inside Docker containers. Runs six sequential checks covering the full debugging chain from container runtime mode through MagicDNS resolution.

What this skill does

1. Detects whether the container runs in kernel or userspace mode.
2. Verifies the TUN interface exists with a Tailscale IP.
3. Checks the DNS resolver chain for misrouted queries.
4. Confirms 100.100.100.100 routes through the container's Tailscale.
5. Detects multi-tailnet conflicts between host and container.
6. Validates MagicDNS end-to-end with a name resolution test.

Common triggers