A model not under its provider's own models.dev vendor (a relay or provider of the user's, a live id that doesn't match, or a preview/-exp or typed id Known looks up) took the levels most listed for it across all of models.dev. For mimo-v2.6-flash those are the resellers' (llmgateway, counted once per upstream host it lists, and requesty, up to max), while Xiaomi lists it with a thinking switch alone. OpenCode was offered variants up to max, Pi and Codex the same levels, and the gateway passed max on unchanged (fitEffort keeps an effort when no levels are known), which Xiaomi turned away with a 400. The same held for Zhipu's glm-5/5.1/5v-turbo, Kimi k2.6, MiniMax M2.x, gemma-4 and others whose makers give no levels while resellers give up to max.
Now catalog.ListedBy looks a model up in given catalogs (vendor prefix, case, a ':free' or '(…)' suffix aside) and gives the levels listed there, none for a switch or no options, and skips an entry with a token budget alone (Claude 4.5), which says nothing of efforts. Known looks in the provider's own catalogs first, and every borrow (Known, effortsOf) asks the makers' catalogs (vendor presets, less Groq and Ollama Cloud, marked Hosts as they serve others' models) before the crowd. The crowd vote counts a provider once per list, so an aggregator listing a model under several hosts no longer outvotes the rest. Provider.Levelless says a model is known to have no levels, and the gateway (fitFor, on the direct and fallback paths) sends such a model no more than high; a model whose levels are simply unknown is still sent what was asked.
Tests: TestEffortsOfOneVoteAProvider and TestListedBy (catalog); TestMakerLevelsBeforeResellers (provider: Xiaomi's preset, a preview left out of the list and a relay get no levels, an unlisted model and a budget-only Claude one still borrow, Levelless); TestOpenCodeNoResellerLevelsForSwitchModel (opencode.json has empty variants for Xiaomi's and a relay's mimo, three for a reseller-only model; Pi has no reasoning or thinkingLevelMap for mimo); TestSwitchModelSentNoMoreThanHigh (gateway: mimo asked max/xhigh sent high, low as asked, an unknown model max). The agent and gateway tests fail on main. An audit of every preset against the current models.dev snapshot found the cases above. Not tested with a real Xiaomi key or a running OpenCode. go build -tags nogui (and linux, windows), go test -tags nogui ./... pass.
yetone