fix(ai): use parametersJsonSchema for Google tool declarations, revert Antigravity opus model

- Use parametersJsonSchema instead of parameters for Gemini tool declarations
  to support full JSON Schema (anyOf, oneOf, const, etc.)
- Keep legacy parameters field for Claude models on Cloud Code Assist, where
  the API translates parameters into Anthropic's input_schema
- Revert claude-opus-4-6-thinking back to claude-opus-4-5-thinking (model
  doesn't exist on the Antigravity endpoint)

fixes #1398

packages/ai/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Use `parametersJsonSchema` for Google provider tool declarations to support full JSON Schema (anyOf, oneOf, const, etc.) ([#1398](https://github.com/badlogic/pi-mono/issues/1398) by [@jarib](https://github.com/jarib))
+- Reverted incorrect Antigravity model change: `claude-opus-4-6-thinking` back to `claude-opus-4-5-thinking` (model doesn't exist on Antigravity endpoint)
+
 ## [0.52.8] - 2026-02-07
 
 ### Added

packages/ai/scripts/generate-models.ts

@@ -1021,8 +1021,8 @@ async function generateModels() {
 			maxTokens: 64000,
 		},
 		{
-			id: "claude-opus-4-6-thinking",
+			id: "claude-opus-4-5-thinking",
-			name: "Claude Opus 4.6 Thinking (Antigravity)",
+			name: "Claude Opus 4.5 Thinking (Antigravity)",
 			api: "google-gemini-cli",
 			provider: "google-antigravity",
 			baseUrl: ANTIGRAVITY_ENDPOINT,

packages/ai/src/models.generated.ts

@@ -2971,9 +2971,9 @@ export const MODELS = {
 		} satisfies Model<"google-generative-ai">,
 	},
 	"google-antigravity": {
-		"claude-opus-4-6-thinking": {
+		"claude-opus-4-5-thinking": {
-			id: "claude-opus-4-6-thinking",
+			id: "claude-opus-4-5-thinking",
-			name: "Claude Opus 4.6 Thinking (Antigravity)",
+			name: "Claude Opus 4.5 Thinking (Antigravity)",
 			api: "google-gemini-cli",
 			provider: "google-antigravity",
 			baseUrl: "https://daily-cloudcode-pa.sandbox.googleapis.com",

packages/ai/src/providers/google-gemini-cli.ts

@@ -953,7 +953,10 @@ export function buildRequest(
 	}
 
 	if (context.tools && context.tools.length > 0) {
-		request.tools = convertTools(context.tools);
+		// Claude models on Cloud Code Assist need the legacy `parameters` field;
+		// the API translates it into Anthropic's `input_schema`.
+		const useParameters = model.id.startsWith("claude-");
+		request.tools = convertTools(context.tools, useParameters);
 		if (options.toolChoice) {
 			request.toolConfig = {
 				functionCallingConfig: {

packages/ai/src/providers/google-shared.ts

@@ -2,7 +2,7 @@
  * Shared utilities for Google Generative AI and Google Cloud Code Assist providers.
  */
 
-import { type Content, FinishReason, FunctionCallingConfigMode, type Part, type Schema } from "@google/genai";
+import { type Content, FinishReason, FunctionCallingConfigMode, type Part } from "@google/genai";
 import type { Context, ImageContent, Model, StopReason, TextContent, Tool } from "../types.js";
 import { sanitizeSurrogates } from "../utils/sanitize-unicode.js";
 import { transformMessages } from "./transform-messages.js";
@@ -232,17 +232,23 @@ export function convertMessages<T extends GoogleApiType>(model: Model<T>, contex
 
 /**
  * Convert tools to Gemini function declarations format.
+ *
+ * By default uses `parametersJsonSchema` which supports full JSON Schema (including
+ * anyOf, oneOf, const, etc.). Set `useParameters` to true to use the legacy `parameters`
+ * field instead (OpenAPI 3.03 Schema). This is needed for Cloud Code Assist with Claude
+ * models, where the API translates `parameters` into Anthropic's `input_schema`.
  */
 export function convertTools(
 	tools: Tool[],
-): { functionDeclarations: { name: string; description?: string; parameters: Schema }[] }[] | undefined {
+	useParameters = false,
+): { functionDeclarations: Record<string, unknown>[] }[] | undefined {
 	if (tools.length === 0) return undefined;
 	return [
 		{
 			functionDeclarations: tools.map((tool) => ({
 				name: tool.name,
 				description: tool.description,
-				parameters: tool.parameters as Schema,
+				...(useParameters ? { parameters: tool.parameters } : { parametersJsonSchema: tool.parameters }),
 			})),
 		},
 	];

packages/coding-agent/test/compaction-thinking-model.test.ts

@@ -57,7 +57,7 @@ describe.skipIf(!HAS_ANTIGRAVITY_AUTH)("Compaction with thinking models (Antigra
 	});
 
 	function createSession(
-		modelId: "claude-opus-4-6-thinking" | "claude-sonnet-4-5",
+		modelId: "claude-opus-4-5-thinking" | "claude-sonnet-4-5",
 		thinkingLevel: ThinkingLevel = "high",
 	) {
 		const model = getModel("google-antigravity", modelId);
@@ -97,8 +97,8 @@ describe.skipIf(!HAS_ANTIGRAVITY_AUTH)("Compaction with thinking models (Antigra
 		return session;
 	}
 
-	it("should compact successfully with claude-opus-4-6-thinking and thinking level high", async () => {
+	it("should compact successfully with claude-opus-4-5-thinking and thinking level high", async () => {
-		createSession("claude-opus-4-6-thinking", "high");
+		createSession("claude-opus-4-5-thinking", "high");
 
 		// Send a simple prompt
 		await session.prompt("Write down the first 10 prime numbers.");