`switch.sh --list` showed every slug regardless of topology, so a
single-GPU box listed dual/multi configs it can't actually run — noise.
Filter `--list` to the topologies the detected GPU count supports:
1 GPU -> single only, 2 -> single+dual, 4+ -> everything. Detection
reuses switch_topology_from_gpus (CUDA/NVIDIA_VISIBLE_DEVICES, then
nvidia-smi) mapped to a topology rank.
- `--all` (and the `--list-all` alias) bypass the filter for
discoverability; --list is deferred until args are parsed so
`--list --all` works in either order.
- Don't silently hide: print a one-line note naming the detected GPU
count and exactly which topologies were hidden, plus a `(+N … hidden
— --all)` tally in the header. No note under --all / when nothing is
hidden.
- Fail-open: with no detection signal (no selector, no nvidia-smi) show
ALL — never hide off a guessed "single" fallback.
- Counts (header + per-model) reflect the visible set; PR-A health
markers/grouping and PR-B Defaults view unchanged.
New test scripts/tests/test-list-topology-filter.sh covers 1/2-GPU
filtering, --all, --list-all, order independence, the --all-without-list
guard, and fail-open. Docs: --help usage, FAQ model-switch entry, README.
Co-authored-by: noonghunna <[email protected]>
Co-authored-by: Claude Opus 4.8 (1M context) <[email protected]>
