fix(coding-agent): skip unauthenticated default model

closes #6231

packages/coding-agent/CHANGELOG.md

@@ -9,6 +9,7 @@
 
 ### Fixed
 
+- Fixed startup model selection to skip unauthenticated saved defaults so configured local custom models can be selected instead ([#6231](https://github.com/earendil-works/pi/issues/6231)).
 - Fixed Escape aborts to clear runs stuck in extension context hooks that ignore abort signals ([#6234](https://github.com/earendil-works/pi/issues/6234)).
 - Fixed the question extension example to run question tool calls sequentially so multiple questions in one assistant turn remain answerable ([#6189](https://github.com/earendil-works/pi/issues/6189)).
 - Fixed `/login` to report auth storage persistence failures instead of claiming credentials were saved when `auth.json` is locked ([#6223](https://github.com/earendil-works/pi/issues/6223)).

packages/coding-agent/src/core/model-resolver.ts

@@ -596,10 +596,10 @@ export async function findInitialModel(options: {
 		};
 	}
 
-	// 3. Try saved default from settings
+	// 3. Try saved default from settings if auth is configured.
 	if (defaultProvider && defaultModelId) {
 		const found = modelRegistry.find(defaultProvider, defaultModelId);
-		if (found) {
+		if (found && modelRegistry.hasConfiguredAuth(found)) {
 			model = found;
 			if (defaultThinkingLevel) {
 				thinkingLevel = defaultThinkingLevel;

packages/coding-agent/test/model-resolver.test.ts

@@ -648,4 +648,43 @@ describe("default model selection", () => {
 		expect(result.model?.provider).toBe("vercel-ai-gateway");
 		expect(result.model?.id).toBe("anthropic/claude-opus-4-6");
 	});
+
+	test("findInitialModel ignores an unauthenticated saved default", async () => {
+		const savedDeepSeekModel: Model<"anthropic-messages"> = {
+			id: "deepseek-v4-flash",
+			name: "DeepSeek V4 Flash",
+			api: "anthropic-messages",
+			provider: "deepseek",
+			baseUrl: "https://api.deepseek.com",
+			reasoning: true,
+			input: ["text"],
+			cost: { input: 1, output: 2, cacheRead: 0.1, cacheWrite: 1 },
+			contextWindow: 128000,
+			maxTokens: 8192,
+		};
+		const localDeepSeekModel: Model<"anthropic-messages"> = {
+			...savedDeepSeekModel,
+			provider: "spark-two",
+			baseUrl: "http://spark-two:8000/v1",
+		};
+		const registry = {
+			find: (provider: string, modelId: string) =>
+				provider === savedDeepSeekModel.provider && modelId === savedDeepSeekModel.id
+					? savedDeepSeekModel
+					: undefined,
+			hasConfiguredAuth: (model: Model<"anthropic-messages">) => model.provider === "spark-two",
+			getAvailable: async () => [localDeepSeekModel],
+		} as unknown as Parameters<typeof findInitialModel>[0]["modelRegistry"];
+
+		const result = await findInitialModel({
+			scopedModels: [],
+			isContinuing: false,
+			defaultProvider: "deepseek",
+			defaultModelId: "deepseek-v4-flash",
+			modelRegistry: registry,
+		});
+
+		expect(result.model?.provider).toBe("spark-two");
+		expect(result.model?.id).toBe("deepseek-v4-flash");
+	});
 });