fix(pi): stop offering extension-only models for text generation

apps/server/src/textGeneration/CodexTextGeneration.test.ts

@@ -546,6 +546,8 @@ const PREFLIGHT_PRIMARY_STATES = [
   "not installed, fallback disabled for project",
   "signed out",
   "signed out, fallback failed",
+  "cannot generate text",
+  "model cannot generate text",
 ] as const;
 
 it.effect.each(PREFLIGHT_PRIMARY_STATES)("text generation preflight: %s", (primaryState) =>
@@ -590,6 +592,22 @@ it.effect.each(PREFLIGHT_PRIMARY_STATES)("text generation preflight: %s", (prima
         ...(primaryState === "signed out, fallback failed" && instanceId === fallback
           ? { status: "error", auth: { status: "unknown" } }
           : {}),
+        ...(primaryState === "cannot generate text" && instanceId === primary
+          ? { supportsTextGeneration: false }
+          : {}),
+        ...(primaryState === "model cannot generate text" && instanceId === primary
+          ? {
+              models: [
+                {
+                  slug: selection.model,
+                  name: selection.model,
+                  isCustom: false,
+                  supportsTextGeneration: false,
+                  capabilities: null,
+                },
+              ],
+            }
+          : {}),
         ...(primaryState === "exhausted" && instanceId === primary
           ? {
               usageLimits: {

apps/server/src/textGeneration/TextGeneration.ts

@@ -108,8 +108,11 @@ export const make = Effect.gen(function* () {
     const unusable =
       textGeneratorCannotRun ||
       (selected?.enabled === true &&
-        selected.status === "error" &&
-        (!selected.installed || selected.auth.status === "unauthenticated"));
+        (!isProviderTextGenerationCapable(selected) ||
+          selected.models.find((model) => model.slug === selection.model)
+            ?.supportsTextGeneration === false ||
+          (selected.status === "error" &&
+            (!selected.installed || selected.auth.status === "unauthenticated"))));
     if (unusable || exhaustedUsageWindow(selected, now, selection.model)) {
       const settings = yield* serverSettings.getSettings.pipe(
         Effect.mapError(

apps/web/src/components/settings/SettingsPanels.tsx

@@ -67,7 +67,7 @@ import { SnoozePresetsRow } from "./SnoozePresetsSettings";
 import { useDesktopUpdateState } from "../../state/desktopUpdate";
 import { managedTelemetryOffMessage, usePrimaryManagedPolicy } from "../../state/managedPolicy";
 import {
-  getCustomModelOptionsByInstance,
+  getTextGenerationModelOptionsByInstance,
   resolveAppModelSelectionState,
   selectsPlanAgent,
 } from "../../modelSelection";
@@ -1743,7 +1743,7 @@ export function ThreadsSettingsPanel() {
   );
   const textGenProvider: ProviderDriverKind =
     textGenInstanceEntry?.driverKind ?? DEFAULT_DRIVER_KIND;
-  const textGenerationModelOptionsByInstance = getCustomModelOptionsByInstance(
+  const textGenerationModelOptionsByInstance = getTextGenerationModelOptionsByInstance(
     settings,
     textGenerationProviders,
     textGenInstanceId,
@@ -1756,6 +1756,7 @@ export function ThreadsSettingsPanel() {
   const textGenerationModelDisabledReason = useScopedModelDisabledReason(
     settings,
     textGenerationModelInstanceEntries,
+    true,
   );
   const mixedAddProjectBaseDirectory = useScopedSettingsMixed(["addProjectBaseDirectory"]);
   const mixedTextGenerationModel = useScopedSettingsMixed(["textGenerationModelSelection"]);

apps/web/src/components/settings/SourceControlWritingSettings.tsx

@@ -23,7 +23,7 @@ import { useSettingsScope } from "./SettingsScopeContext";
 import { providerInstanceEntriesFor } from "../../providerInstances";
 import { useTextGenerationTargets } from "../../textGenerators";
 import {
-  getCustomModelOptionsByInstance,
+  getTextGenerationModelOptionsByInstance,
   resolveAppModelSelectionState,
   selectsPlanAgent,
 } from "../../modelSelection";
@@ -151,13 +151,13 @@ export function SourceControlWritingSettingsSection() {
     (entry) =>
       entry.instanceId === defaultModelSelection.instanceId && entry.enabled && entry.isAvailable,
   );
-  const modelOptionsByInstance = getCustomModelOptionsByInstance(
+  const modelOptionsByInstance = getTextGenerationModelOptionsByInstance(
     settings,
     projectEffectiveTextGenerationProviders,
     activeSelection.instanceId,
     activeSelection.model,
   );
-  const writerModelDisabledReason = useScopedModelDisabledReason(settings, writerEntries);
+  const writerModelDisabledReason = useScopedModelDisabledReason(settings, writerEntries, true);
   const writerInstanceEntry = writerEntries.find(
     (entry) => entry.instanceId === activeSelection.instanceId,
   );
@@ -179,7 +179,7 @@ export function SourceControlWritingSettingsSection() {
     },
     projectAgentProviders,
   );
-  const reviewGuideModelOptionsByInstance = getCustomModelOptionsByInstance(
+  const reviewGuideModelOptionsByInstance = getTextGenerationModelOptionsByInstance(
     settings,
     projectAgentProviders,
     reviewGuideSelection.instanceId,
@@ -595,7 +595,21 @@ export function SourceControlWritingSettingsSection() {
                 <Switch
                   checked={usesDedicatedModel}
                   disabled={!usesDedicatedModel && !canEnableDedicatedModel}
-                  onCheckedChange={(checked) =>
+                  onCheckedChange={(checked) => {
+                    if (checked) {
+                      const reason = writerModelDisabledReason(
+                        defaultModelSelection.instanceId,
+                        defaultModelSelection.model,
+                      );
+                      if (reason) {
+                        toastManager.add({
+                          type: "error",
+                          title: "Writer model not saved",
+                          description: reason,
+                        });
+                        return;
+                      }
+                    }
                     updateSettings({
                       sourceControlWriterModelSelection: checked
                         ? createModelSelection(
@@ -604,8 +618,8 @@ export function SourceControlWritingSettingsSection() {
                             defaultModelSelection.options,
                           )
                         : null,
-                    })
-                  }
+                    });
+                  }}
                   aria-label="Use a separate source control writer model"
                 />
               </div>

apps/web/src/components/settings/TextGeneratorsSettings.tsx

@@ -28,7 +28,7 @@ import {
   textGeneratorBrand,
   textGeneratorDisplayName,
 } from "../../textGenerators";
-import { getCustomModelOptionsByInstance } from "../../modelSelection";
+import { getTextGenerationModelOptionsByInstance } from "../../modelSelection";
 import { ProviderInstanceIcon } from "../chat/ProviderInstanceIcon";
 import { ProviderModelPicker } from "../chat/ProviderModelPicker";
 import {
@@ -563,7 +563,7 @@ function TextGenerationTaskPicker({
           model={selection.model}
           lockedProvider={null}
           instanceEntries={targets.entries}
-          modelOptionsByInstance={getCustomModelOptionsByInstance(
+          modelOptionsByInstance={getTextGenerationModelOptionsByInstance(
             settings,
             targets.providers,
             selection.instanceId,

apps/web/src/components/settings/VoiceSettingsPanel.tsx

@@ -72,7 +72,7 @@ import {
 import { updateClientSettings, useClientSettings } from "../../hooks/useSettings";
 import { runEnvironmentSpeech } from "../../speech/runEnvironmentSpeech";
 import {
-  getCustomModelOptionsByInstance,
+  getTextGenerationModelOptionsByInstance,
   resolveAppModelSelectionState,
 } from "../../modelSelection";
 import { useTextGenerationTargets } from "../../textGenerators";
@@ -531,14 +531,14 @@ function CleanupModelRow() {
     },
     textGenerationProviders,
   );
-  const modelOptionsByInstance = getCustomModelOptionsByInstance(
+  const modelOptionsByInstance = getTextGenerationModelOptionsByInstance(
     settings,
     textGenerationProviders,
     selection.instanceId,
     selection.model,
   );
   const instanceEntry = instanceEntries.find((entry) => entry.instanceId === selection.instanceId);
-  const modelDisabledReason = useScopedModelDisabledReason(settings, instanceEntries);
+  const modelDisabledReason = useScopedModelDisabledReason(settings, instanceEntries, true);
   const setModel = (next: ReturnType<typeof createModelSelection>) => {
     const reason = modelDisabledReason(next.instanceId, next.model);
     if (reason) {

apps/web/src/components/settings/useScopedModelAvailability.ts

@@ -5,7 +5,10 @@ import {
 } from "@t3tools/contracts";
 
 import { mergeEnvironmentSettings } from "../../hooks/useSettings";
-import { getCustomModelOptionsByInstance } from "../../modelSelection";
+import {
+  getCustomModelOptionsByInstance,
+  getTextGenerationModelOptionsByInstance,
+} from "../../modelSelection";
 import {
   applyProviderInstanceSettings,
   deriveProviderInstanceEntries,
@@ -17,6 +20,7 @@ import { useSettingsScope } from "./SettingsScopeContext";
 export function useScopedModelDisabledReason(
   settings: UnifiedSettings,
   entries: readonly ProviderInstanceEntry[],
+  textGeneration = false,
 ) {
   const { targets } = useSettingsScope();
   const { environments } = useEnvironments();
@@ -48,7 +52,10 @@ export function useScopedModelDisabledReason(
         candidate.settings,
         candidate.projectId,
       ).find((option) => option.instanceId === instanceId);
-      const options = getCustomModelOptionsByInstance(
+      const optionsForInstance = textGeneration
+        ? getTextGenerationModelOptionsByInstance
+        : getCustomModelOptionsByInstance;
+      const options = optionsForInstance(
         mergeEnvironmentSettings(candidate.settings, settings),
         providers,
       ).get(instanceId);

apps/web/src/modelSelection.test.ts

@@ -25,6 +25,8 @@ import {
 import {
   defaultModelSelectionsAreMixed,
   getAppModelOptionsForInstance,
+  getCustomModelOptionsByInstance,
+  getTextGenerationModelOptionsByInstance,
   resolveAppModelSelectionForInstance,
   resolveAppModelSelectionState,
   resolveEffectiveDefaultModelSelection,
@@ -917,6 +919,60 @@ describe("instance-scoped model selection", () => {
       NO_PROVIDER_MODEL_SELECTION,
     );
   });
+
+  it("excludes customized extension models while preserving unknown custom and thread models", () => {
+    const pi = provider({
+      provider: ProviderDriverKind.make("pi"),
+      instanceId: "pi",
+      models: ["default", "demo/demo-model"],
+    });
+    const providers = [
+      {
+        ...pi,
+        models: pi.models.map((model) =>
+          model.slug === "demo/demo-model" ? { ...model, supportsTextGeneration: false } : model,
+        ),
+      },
+    ];
+    const settings: UnifiedSettings = {
+      ...DEFAULT_UNIFIED_SETTINGS,
+      providerInstances: {
+        [pi.instanceId]: {
+          driver: ProviderDriverKind.make("pi"),
+          config: {
+            customModels: [
+              { slug: "demo/demo-model", name: "My extension model" },
+              { slug: "unknown/model", name: "My custom model" },
+            ],
+          },
+        },
+      },
+      textGenerationModelSelection: createModelSelection(pi.instanceId, "demo/demo-model"),
+    };
+    const supported = providers.filter((provider) => provider.supportsTextGeneration !== false);
+    expect(
+      getTextGenerationModelOptionsByInstance(settings, supported, pi.instanceId, "demo/demo-model")
+        .get(pi.instanceId)
+        ?.map((option) => option.slug),
+    ).toEqual(["default", "unknown/model"]);
+    expect(resolveAppModelSelectionState(settings, supported)).toEqual(
+      createModelSelection(pi.instanceId, "default"),
+    );
+    expect(
+      resolveAppModelSelectionState(
+        {
+          ...settings,
+          textGenerationModelSelection: createModelSelection(pi.instanceId, "unknown/model"),
+        },
+        supported,
+      ).model,
+    ).toBe("unknown/model");
+    expect(
+      getCustomModelOptionsByInstance(settings, providers)
+        .get(pi.instanceId)
+        ?.map((option) => option.slug),
+    ).toEqual(["default", "demo/demo-model", "unknown/model"]);
+  });
 });
 
 describe("resolveAppModelSelectionState with the opencode plan agent", () => {

apps/web/src/modelSelection.ts

@@ -366,6 +366,42 @@ export function getCustomModelOptionsByInstance(
   return out;
 }
 
+function getTextGenerationModelOptionsForInstance(
+  settings: UnifiedSettings,
+  entry: ProviderInstanceEntry,
+  selectedModel?: string | null,
+): AppModelOption[] {
+  const unsupported = new Set(
+    entry.models
+      .filter((model) => model.supportsTextGeneration === false)
+      .map((model) => model.slug),
+  );
+  // Filter after custom entries are rebuilt so a display-name override cannot restore a model.
+  return getAppModelOptionsForInstance(settings, entry, selectedModel).filter(
+    (option) => !unsupported.has(option.slug),
+  );
+}
+
+export function getTextGenerationModelOptionsByInstance(
+  settings: UnifiedSettings,
+  providers: ReadonlyArray<ServerProvider>,
+  selectedInstanceId?: ProviderInstanceId | null,
+  selectedModel?: string | null,
+): ReadonlyMap<ProviderInstanceId, ReadonlyArray<ModelEsque>> {
+  return new Map(
+    deriveProviderInstanceEntries(
+      providers.filter((provider) => provider.supportsTextGeneration !== false),
+    ).map((entry) => [
+      entry.instanceId,
+      getTextGenerationModelOptionsForInstance(
+        settings,
+        entry,
+        entry.instanceId === selectedInstanceId ? selectedModel : null,
+      ),
+    ]),
+  );
+}
+
 export function selectsPlanAgent(options: ModelSelection["options"]): boolean {
   return options?.some((option) => option.id === "agent" && option.value === "plan") ?? false;
 }
@@ -390,21 +426,17 @@ export function resolveAppModelSelectionState(
   if (entry) {
     const selectedModel = selectedEntry ? selection.model : null;
     // Use the cheap generation default; the catalog default is the expensive chat flagship.
-    const options = getAppModelOptionsForInstance(settings, entry);
+    const options = getTextGenerationModelOptionsForInstance(settings, entry);
     const model =
       resolveSelectableModel(entry.driverKind, selectedModel, options) ??
       resolveSelectableModel(
         entry.driverKind,
         DEFAULT_TEXT_GENERATION_MODEL_BY_PROVIDER[entry.driverKind],
         options,
       ) ??
-      resolveAppModelSelectionForInstance(
-        entry.instanceId,
-        settings,
-        supportedProviders,
-        selectedModel,
-      ) ??
-      entry.models[0]?.slug ??
+      options.find((option) => option.isDefault)?.slug ??
+      options[0]?.slug ??
+      entry.models.find((model) => model.supportsTextGeneration !== false)?.slug ??
       DEFAULT_TEXT_GENERATION_MODEL_BY_PROVIDER[entry.driverKind];
     if (!model) {
       return createModelSelection(entry.instanceId, "", []);

packages/contracts/src/server.ts

@@ -83,6 +83,9 @@ export const ServerProviderModel = Schema.Struct({
   isCustom: Schema.Boolean,
   isDefault: Schema.optional(Schema.Boolean),
   isLegacy: Schema.optional(Schema.Boolean),
+  // False when the provider can run this model in sessions but not for
+  // application text generation. Absent means supported.
+  supportsTextGeneration: Schema.optional(Schema.Boolean),
   capabilities: Schema.NullOr(ModelCapabilities),
 });
 export type ServerProviderModel = typeof ServerProviderModel.Type;