fix(FN-2662): honor project model overrides and stabilize tests

packages/core/src/__tests__/model-resolution.test.ts

@@ -0,0 +1,119 @@
+import { describe, expect, it } from "vitest";
+import {
+  resolveExecutionSettingsModel,
+  resolvePlanningSettingsModel,
+  resolveProjectDefaultModel,
+  resolveTaskExecutionModel,
+  resolveTaskPlanningModel,
+  resolveTaskValidatorModel,
+  resolveTitleSummarizerSettingsModel,
+  resolveValidatorSettingsModel,
+} from "../model-resolution.js";
+
+describe("model-resolution", () => {
+  it("prefers the project default override over the global default", () => {
+    expect(
+      resolveProjectDefaultModel({
+        defaultProviderOverride: "openai",
+        defaultModelIdOverride: "gpt-4o",
+        defaultProvider: "anthropic",
+        defaultModelId: "claude-sonnet-4-5",
+      }),
+    ).toEqual({ provider: "openai", modelId: "gpt-4o" });
+  });
+
+  it("uses the execution lane before the project default override", () => {
+    expect(
+      resolveExecutionSettingsModel({
+        executionProvider: "google",
+        executionModelId: "gemini-2.5-pro",
+        defaultProviderOverride: "openai",
+        defaultModelIdOverride: "gpt-4o",
+      }),
+    ).toEqual({ provider: "google", modelId: "gemini-2.5-pro" });
+  });
+
+  it("falls back from planning global to the project default override", () => {
+    expect(
+      resolvePlanningSettingsModel({
+        defaultProviderOverride: "openai",
+        defaultModelIdOverride: "gpt-4o-mini",
+      }),
+    ).toEqual({ provider: "openai", modelId: "gpt-4o-mini" });
+  });
+
+  it("falls back from validator global to the project default override", () => {
+    expect(
+      resolveValidatorSettingsModel({
+        defaultProviderOverride: "anthropic",
+        defaultModelIdOverride: "claude-opus-4",
+      }),
+    ).toEqual({ provider: "anthropic", modelId: "claude-opus-4" });
+  });
+
+  it("uses title summarizer global, then project planning, then project default override", () => {
+    expect(
+      resolveTitleSummarizerSettingsModel({
+        titleSummarizerGlobalProvider: "openai",
+        titleSummarizerGlobalModelId: "gpt-4.1",
+        planningProvider: "google",
+        planningModelId: "gemini-2.5-pro",
+        defaultProviderOverride: "anthropic",
+        defaultModelIdOverride: "claude-sonnet-4-5",
+      }),
+    ).toEqual({ provider: "openai", modelId: "gpt-4.1" });
+
+    expect(
+      resolveTitleSummarizerSettingsModel({
+        planningProvider: "google",
+        planningModelId: "gemini-2.5-pro",
+        defaultProviderOverride: "anthropic",
+        defaultModelIdOverride: "claude-sonnet-4-5",
+      }),
+    ).toEqual({ provider: "google", modelId: "gemini-2.5-pro" });
+
+    expect(
+      resolveTitleSummarizerSettingsModel({
+        defaultProviderOverride: "anthropic",
+        defaultModelIdOverride: "claude-sonnet-4-5",
+      }),
+    ).toEqual({ provider: "anthropic", modelId: "claude-sonnet-4-5" });
+  });
+
+  it("uses task overrides before settings fallbacks", () => {
+    expect(
+      resolveTaskExecutionModel(
+        {
+          modelProvider: "openai",
+          modelId: "gpt-4o",
+        },
+        {
+          executionProvider: "anthropic",
+          executionModelId: "claude-sonnet-4-5",
+        },
+      ),
+    ).toEqual({ provider: "openai", modelId: "gpt-4o" });
+
+    expect(
+      resolveTaskValidatorModel(
+        {},
+        {
+          defaultProviderOverride: "anthropic",
+          defaultModelIdOverride: "claude-sonnet-4-5",
+        },
+      ),
+    ).toEqual({ provider: "anthropic", modelId: "claude-sonnet-4-5" });
+
+    expect(
+      resolveTaskPlanningModel(
+        {},
+        {
+          planningGlobalProvider: "openai",
+          planningGlobalModelId: "gpt-4.1",
+          defaultProviderOverride: "anthropic",
+          defaultModelIdOverride: "claude-sonnet-4-5",
+        },
+      ),
+    ).toEqual({ provider: "openai", modelId: "gpt-4.1" });
+  });
+});

packages/core/src/index.ts

@@ -196,6 +196,17 @@ export {
   AiServiceError,
   __resetSummarizeState,
 } from "./ai-summarize.js";
+export {
+  resolveExecutionSettingsModel,
+  resolvePlanningSettingsModel,
+  resolveProjectDefaultModel,
+  resolveTaskExecutionModel,
+  resolveTaskPlanningModel,
+  resolveTaskValidatorModel,
+  resolveTitleSummarizerSettingsModel,
+  resolveValidatorSettingsModel,
+} from "./model-resolution.js";
+export type { ResolvedModelSelection } from "./model-resolution.js";
 
 // ── Memory Compaction ─────────────────────────────────────────────────
 

packages/core/src/model-resolution.ts

@@ -0,0 +1,148 @@
+import type { Settings } from "./types.js";
+
+export interface ResolvedModelSelection {
+  provider?: string;
+  modelId?: string;
+}
+
+type ModelPair =
+  | ResolvedModelSelection
+  | {
+      provider?: string | null;
+      modelId?: string | null;
+    }
+  | undefined;
+
+type TaskModelLike = {
+  modelProvider?: string | null;
+  modelId?: string | null;
+  validatorModelProvider?: string | null;
+  validatorModelId?: string | null;
+  planningModelProvider?: string | null;
+  planningModelId?: string | null;
+};
+
+function hasCompleteModelPair(pair: ModelPair): pair is { provider: string; modelId: string } {
+  return Boolean(pair?.provider && pair?.modelId);
+}
+
+function pickFirstModelPair(...pairs: ModelPair[]): ResolvedModelSelection {
+  for (const pair of pairs) {
+    if (hasCompleteModelPair(pair)) {
+      return { provider: pair.provider, modelId: pair.modelId };
+    }
+  }
+  return {};
+}
+
+export function resolveProjectDefaultModel(settings?: Partial<Settings>): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: settings?.defaultProviderOverride,
+      modelId: settings?.defaultModelIdOverride,
+    },
+    {
+      provider: settings?.defaultProvider,
+      modelId: settings?.defaultModelId,
+    },
+  );
+}
+
+export function resolveExecutionSettingsModel(settings?: Partial<Settings>): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: settings?.executionProvider,
+      modelId: settings?.executionModelId,
+    },
+    {
+      provider: settings?.executionGlobalProvider,
+      modelId: settings?.executionGlobalModelId,
+    },
+    resolveProjectDefaultModel(settings),
+  );
+}
+
+export function resolvePlanningSettingsModel(settings?: Partial<Settings>): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: settings?.planningProvider,
+      modelId: settings?.planningModelId,
+    },
+    {
+      provider: settings?.planningGlobalProvider,
+      modelId: settings?.planningGlobalModelId,
+    },
+    resolveProjectDefaultModel(settings),
+  );
+}
+
+export function resolveValidatorSettingsModel(settings?: Partial<Settings>): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: settings?.validatorProvider,
+      modelId: settings?.validatorModelId,
+    },
+    {
+      provider: settings?.validatorGlobalProvider,
+      modelId: settings?.validatorGlobalModelId,
+    },
+    resolveProjectDefaultModel(settings),
+  );
+}
+
+export function resolveTitleSummarizerSettingsModel(settings?: Partial<Settings>): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: settings?.titleSummarizerProvider,
+      modelId: settings?.titleSummarizerModelId,
+    },
+    {
+      provider: settings?.titleSummarizerGlobalProvider,
+      modelId: settings?.titleSummarizerGlobalModelId,
+    },
+    {
+      provider: settings?.planningProvider,
+      modelId: settings?.planningModelId,
+    },
+    resolveProjectDefaultModel(settings),
+  );
+}
+
+export function resolveTaskExecutionModel(
+  task: TaskModelLike,
+  settings?: Partial<Settings>,
+): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: task.modelProvider,
+      modelId: task.modelId,
+    },
+    resolveExecutionSettingsModel(settings),
+  );
+}
+
+export function resolveTaskValidatorModel(
+  task: TaskModelLike,
+  settings?: Partial<Settings>,
+): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: task.validatorModelProvider,
+      modelId: task.validatorModelId,
+    },
+    resolveValidatorSettingsModel(settings),
+  );
+}
+
+export function resolveTaskPlanningModel(
+  task: TaskModelLike,
+  settings?: Partial<Settings>,
+): ResolvedModelSelection {
+  return pickFirstModelPair(
+    {
+      provider: task.planningModelProvider,
+      modelId: task.planningModelId,
+    },
+    resolvePlanningSettingsModel(settings),
+  );
+}

packages/core/src/types.ts

@@ -3376,3 +3376,14 @@ export { PROMPT_KEY_CATALOG } from "./prompt-overrides.js";
 // Re-exported here so the dashboard's `@fusion/core` → types.ts alias resolves
 // client-side consumers (see packages/dashboard/vite.config.ts).
 export { getErrorMessage } from "./error-message.js";
+export {
+  resolveExecutionSettingsModel,
+  resolvePlanningSettingsModel,
+  resolveProjectDefaultModel,
+  resolveTaskExecutionModel,
+  resolveTaskPlanningModel,
+  resolveTaskValidatorModel,
+  resolveTitleSummarizerSettingsModel,
+  resolveValidatorSettingsModel,
+} from "./model-resolution.js";
+export type { ResolvedModelSelection } from "./model-resolution.js";