fix(ai): keep image tool results inline for gemini 3+ and antigravity closes #2052

packages/ai/test/google-shared-image-tool-result-routing.test.ts

@@ -0,0 +1,124 @@
+import { describe, expect, it } from "vitest";
+import { convertMessages } from "../src/providers/google-shared.js";
+import type { Context, Model } from "../src/types.js";
+
+function makeModel<TApi extends "google-generative-ai" | "google-gemini-cli">(
+	api: TApi,
+	provider: Model<TApi>["provider"],
+	id: string,
+): Model<TApi> {
+	return {
+		id,
+		name: id,
+		api,
+		provider,
+		baseUrl: "https://example.com",
+		reasoning: true,
+		input: ["text", "image"],
+		cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0 },
+		contextWindow: 128000,
+		maxTokens: 8192,
+	};
+}
+
+function makeContext(model: { api: string; provider: string; id: string }): Context {
+	const now = Date.now();
+	return {
+		messages: [
+			{ role: "user", content: "read the files", timestamp: now },
+			{
+				role: "assistant",
+				content: [
+					{ type: "toolCall", id: "call_a", name: "read", arguments: { path: "a.txt" } },
+					{ type: "toolCall", id: "call_img", name: "read", arguments: { path: "image.png" } },
+					{ type: "toolCall", id: "call_b", name: "read", arguments: { path: "b.txt" } },
+				],
+				api: model.api,
+				provider: model.provider,
+				model: model.id,
+				usage: {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+					totalTokens: 0,
+					cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+				},
+				stopReason: "toolUse",
+				timestamp: now,
+			},
+			{
+				role: "toolResult",
+				toolCallId: "call_a",
+				toolName: "read",
+				content: [{ type: "text", text: "alpha text" }],
+				isError: false,
+				timestamp: now,
+			},
+			{
+				role: "toolResult",
+				toolCallId: "call_img",
+				toolName: "read",
+				content: [{ type: "image", data: "abc", mimeType: "image/png" }],
+				isError: false,
+				timestamp: now,
+			},
+			{
+				role: "toolResult",
+				toolCallId: "call_b",
+				toolName: "read",
+				content: [{ type: "text", text: "beta text" }],
+				isError: false,
+				timestamp: now,
+			},
+		],
+	};
+}
+
+describe("google-shared image tool result routing", () => {
+	it("keeps separate synthetic image turn for Gemini 2.x Google API models", () => {
+		const model = makeModel("google-generative-ai", "google", "gemini-2.5-flash");
+		const contents = convertMessages(model, makeContext(model));
+
+		expect(contents).toHaveLength(5);
+		expect(contents[2].parts?.every((part) => part.functionResponse)).toBe(true);
+		expect(contents[3].parts?.[0]?.text).toBe("Tool result image:");
+		expect(contents[3].parts?.[1]?.inlineData).toBeTruthy();
+		expect(contents[4].parts?.[0]?.functionResponse).toBeTruthy();
+	});
+
+	it("nests image tool results for Gemini 3 Google API models", () => {
+		const model = makeModel("google-generative-ai", "google", "gemini-3-pro-preview");
+		const contents = convertMessages(model, makeContext(model));
+
+		expect(contents).toHaveLength(3);
+		const toolResultTurn = contents[2];
+		expect(toolResultTurn.parts).toHaveLength(3);
+		const imageResponse = toolResultTurn.parts?.[1]?.functionResponse;
+		expect(imageResponse).toBeTruthy();
+		expect(imageResponse?.parts).toHaveLength(1);
+		expect(imageResponse?.parts?.[0]?.inlineData).toBeTruthy();
+	});
+
+	it("nests image tool results for non-Gemini models on Antigravity / Cloud Code Assist", () => {
+		const model = makeModel("google-gemini-cli", "google-antigravity", "claude-sonnet-4-6");
+		const contents = convertMessages(model, makeContext(model));
+
+		expect(contents).toHaveLength(3);
+		const toolResultTurn = contents[2];
+		expect(toolResultTurn.parts).toHaveLength(3);
+		const imageResponse = toolResultTurn.parts?.[1]?.functionResponse;
+		expect(imageResponse).toBeTruthy();
+		expect(imageResponse?.parts).toHaveLength(1);
+		expect(imageResponse?.parts?.[0]?.inlineData).toBeTruthy();
+	});
+
+	it("keeps separate synthetic image turn for Gemini 2.x Cloud Code Assist models", () => {
+		const model = makeModel("google-gemini-cli", "google-gemini-cli", "gemini-2.5-flash");
+		const contents = convertMessages(model, makeContext(model));
+
+		expect(contents).toHaveLength(5);
+		expect(contents[3].parts?.[0]?.text).toBe("Tool result image:");
+		expect(contents[3].parts?.[1]?.inlineData).toBeTruthy();
+	});
+});