Revert "fix(ai): own Anthropic SSE parsing to avoid SDK JSON.parse hard-failures"

This reverts commit 4b926a30a2.

packages/coding-agent/test/agent-session-model-switch-thinking.test.ts

@@ -0,0 +1,79 @@
+import { Agent, type ThinkingLevel } from "@mariozechner/pi-agent-core";
+import { getModel } from "@mariozechner/pi-ai";
+import { describe, expect, it } from "vitest";
+import { AgentSession } from "../src/core/agent-session.js";
+import { AuthStorage } from "../src/core/auth-storage.js";
+import { ModelRegistry } from "../src/core/model-registry.js";
+import { SessionManager } from "../src/core/session-manager.js";
+import { SettingsManager } from "../src/core/settings-manager.js";
+import { createTestResourceLoader } from "./utilities.js";
+
+const reasoningModel = getModel("anthropic", "claude-sonnet-4-5")!;
+const nonReasoningModel = getModel("anthropic", "claude-3-5-haiku-latest")!;
+
+function createSession({
+	thinkingLevel = "high",
+	defaultThinkingLevel = thinkingLevel,
+	scopedModels,
+}: {
+	thinkingLevel?: ThinkingLevel;
+	defaultThinkingLevel?: ThinkingLevel;
+	scopedModels?: Array<{ model: typeof reasoningModel; thinkingLevel?: ThinkingLevel }>;
+} = {}) {
+	const settingsManager = SettingsManager.inMemory({ defaultThinkingLevel });
+	const sessionManager = SessionManager.inMemory();
+	const authStorage = AuthStorage.inMemory();
+	authStorage.setRuntimeApiKey("anthropic", "test-key");
+	const session = new AgentSession({
+		agent: new Agent({
+			getApiKey: () => "test-key",
+			initialState: {
+				model: reasoningModel,
+				systemPrompt: "You are a helpful assistant.",
+				tools: [],
+				thinkingLevel,
+			},
+		}),
+		sessionManager,
+		settingsManager,
+		cwd: process.cwd(),
+		modelRegistry: ModelRegistry.inMemory(authStorage),
+		resourceLoader: createTestResourceLoader(),
+		scopedModels,
+	});
+
+	return { session, sessionManager, settingsManager };
+}
+
+describe("AgentSession model switching", () => {
+	it("preserves the saved thinking preference through non-reasoning models", async () => {
+		const { session, sessionManager, settingsManager } = createSession({
+			scopedModels: [{ model: reasoningModel }, { model: nonReasoningModel }],
+		});
+
+		try {
+			await session.setModel(nonReasoningModel);
+			expect(session.thinkingLevel).toBe("off");
+			expect(settingsManager.getDefaultThinkingLevel()).toBe("high");
+
+			await session.setModel(reasoningModel);
+			expect(session.thinkingLevel).toBe("high");
+
+			await session.cycleModel();
+			expect(session.thinkingLevel).toBe("off");
+			expect(settingsManager.getDefaultThinkingLevel()).toBe("high");
+
+			await session.cycleModel();
+			expect(session.thinkingLevel).toBe("high");
+			expect(settingsManager.getDefaultThinkingLevel()).toBe("high");
+			expect(
+				sessionManager
+					.getEntries()
+					.filter((entry) => entry.type === "thinking_level_change")
+					.map((entry) => entry.thinkingLevel),
+			).toEqual(["off", "high", "off", "high"]);
+		} finally {
+			session.dispose();
+		}
+	});
+});