update

pi-mono-reference/packages/ai/src/providers/google-gemini-cli.ts

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+/**
+ * Google Gemini CLI / Antigravity provider.
+ * Shared implementation for both google-gemini-cli and google-antigravity providers.
+ * Uses the Cloud Code Assist API endpoint to access Gemini and Claude models.
+ */
+
+import type { Content, ThinkingConfig } from "@google/genai";
+import { calculateCost } from "../models.js";
+import type {
+	Api,
+	AssistantMessage,
+	Context,
+	Model,
+	SimpleStreamOptions,
+	StreamFunction,
+	StreamOptions,
+	TextContent,
+	ThinkingBudgets,
+	ThinkingContent,
+	ThinkingLevel,
+	ToolCall,
+} from "../types.js";
+import { AssistantMessageEventStream } from "../utils/event-stream.js";
+import { sanitizeSurrogates } from "../utils/sanitize-unicode.js";
+import {
+	convertMessages,
+	convertTools,
+	isThinkingPart,
+	mapStopReasonString,
+	mapToolChoice,
+	retainThoughtSignature,
+} from "./google-shared.js";
+import { buildBaseOptions, clampReasoning } from "./simple-options.js";
+
+/**
+ * Thinking level for Gemini 3 models.
+ * Mirrors Google's ThinkingLevel enum values.
+ */
+export type GoogleThinkingLevel = "THINKING_LEVEL_UNSPECIFIED" | "MINIMAL" | "LOW" | "MEDIUM" | "HIGH";
+
+export interface GoogleGeminiCliOptions extends StreamOptions {
+	toolChoice?: "auto" | "none" | "any";
+	/**
+	 * Thinking/reasoning configuration.
+	 * - Gemini 2.x models: use `budgetTokens` to set the thinking budget
+	 * - Gemini 3 models (gemini-3-pro-*, gemini-3-flash-*): use `level` instead
+	 *
+	 * When using `streamSimple`, this is handled automatically based on the model.
+	 */
+	thinking?: {
+		enabled: boolean;
+		/** Thinking budget in tokens. Use for Gemini 2.x models. */
+		budgetTokens?: number;
+		/** Thinking level. Use for Gemini 3 models (LOW/HIGH for Pro, MINIMAL/LOW/MEDIUM/HIGH for Flash). */
+		level?: GoogleThinkingLevel;
+	};
+	projectId?: string;
+}
+
+const DEFAULT_ENDPOINT = "https://cloudcode-pa.googleapis.com";
+const ANTIGRAVITY_DAILY_ENDPOINT = "https://daily-cloudcode-pa.sandbox.googleapis.com";
+const ANTIGRAVITY_AUTOPUSH_ENDPOINT = "https://autopush-cloudcode-pa.sandbox.googleapis.com";
+const ANTIGRAVITY_ENDPOINT_FALLBACKS = [
+	ANTIGRAVITY_DAILY_ENDPOINT,
+	ANTIGRAVITY_AUTOPUSH_ENDPOINT,
+	DEFAULT_ENDPOINT,
+] as const;
+// Headers for Gemini CLI (prod endpoint)
+const GEMINI_CLI_HEADERS = {
+	"User-Agent": "google-cloud-sdk vscode_cloudshelleditor/0.1",
+	"X-Goog-Api-Client": "gl-node/22.17.0",
+	"Client-Metadata": JSON.stringify({
+		ideType: "IDE_UNSPECIFIED",
+		platform: "PLATFORM_UNSPECIFIED",
+		pluginType: "GEMINI",
+	}),
+};
+
+// Headers for Antigravity (sandbox endpoint) - requires specific User-Agent
+const DEFAULT_ANTIGRAVITY_VERSION = "1.21.9";
+
+function getAntigravityHeaders() {
+	const version = process.env.PI_AI_ANTIGRAVITY_VERSION || DEFAULT_ANTIGRAVITY_VERSION;
+	return {
+		"User-Agent": `antigravity/${version} darwin/arm64`,
+	};
+}
+
+// Antigravity system instruction (compact version from CLIProxyAPI).
+const ANTIGRAVITY_SYSTEM_INSTRUCTION =
+	"You are Antigravity, a powerful agentic AI coding assistant designed by the Google Deepmind team working on Advanced Agentic Coding." +
+	"You are pair programming with a USER to solve their coding task. The task may require creating a new codebase, modifying or debugging an existing codebase, or simply answering a question." +
+	"**Absolute paths only**" +
+	"**Proactiveness**";
+
+// Counter for generating unique tool call IDs
+let toolCallCounter = 0;
+
+// Retry configuration
+const MAX_RETRIES = 3;
+const BASE_DELAY_MS = 1000;
+const MAX_EMPTY_STREAM_RETRIES = 2;
+const EMPTY_STREAM_BASE_DELAY_MS = 500;
+const CLAUDE_THINKING_BETA_HEADER = "interleaved-thinking-2025-05-14";
+
+/**
+ * Extract retry delay from Gemini error response (in milliseconds).
+ * Checks headers first (Retry-After, x-ratelimit-reset, x-ratelimit-reset-after),
+ * then parses body patterns like:
+ * - "Your quota will reset after 39s"
+ * - "Your quota will reset after 18h31m10s"
+ * - "Please retry in Xs" or "Please retry in Xms"
+ * - "retryDelay": "34.074824224s" (JSON field)
+ */
+export function extractRetryDelay(errorText: string, response?: Response | Headers): number | undefined {
+	const normalizeDelay = (ms: number): number | undefined => (ms > 0 ? Math.ceil(ms + 1000) : undefined);
+
+	const headers = response instanceof Headers ? response : response?.headers;
+	if (headers) {
+		const retryAfter = headers.get("retry-after");
+		if (retryAfter) {
+			const retryAfterSeconds = Number(retryAfter);
+			if (Number.isFinite(retryAfterSeconds)) {
+				const delay = normalizeDelay(retryAfterSeconds * 1000);
+				if (delay !== undefined) {
+					return delay;
+				}
+			}
+			const retryAfterDate = new Date(retryAfter);
+			const retryAfterMs = retryAfterDate.getTime();
+			if (!Number.isNaN(retryAfterMs)) {
+				const delay = normalizeDelay(retryAfterMs - Date.now());
+				if (delay !== undefined) {
+					return delay;
+				}
+			}
+		}
+
+		const rateLimitReset = headers.get("x-ratelimit-reset");
+		if (rateLimitReset) {
+			const resetSeconds = Number.parseInt(rateLimitReset, 10);
+			if (!Number.isNaN(resetSeconds)) {
+				const delay = normalizeDelay(resetSeconds * 1000 - Date.now());
+				if (delay !== undefined) {
+					return delay;
+				}
+			}
+		}
+
+		const rateLimitResetAfter = headers.get("x-ratelimit-reset-after");
+		if (rateLimitResetAfter) {
+			const resetAfterSeconds = Number(rateLimitResetAfter);
+			if (Number.isFinite(resetAfterSeconds)) {
+				const delay = normalizeDelay(resetAfterSeconds * 1000);
+				if (delay !== undefined) {
+					return delay;
+				}
+			}
+		}
+	}
+
+	// Pattern 1: "Your quota will reset after ..." (formats: "18h31m10s", "10m15s", "6s", "39s")
+	const durationMatch = errorText.match(/reset after (?:(\d+)h)?(?:(\d+)m)?(\d+(?:\.\d+)?)s/i);
+	if (durationMatch) {
+		const hours = durationMatch[1] ? parseInt(durationMatch[1], 10) : 0;
+		const minutes = durationMatch[2] ? parseInt(durationMatch[2], 10) : 0;
+		const seconds = parseFloat(durationMatch[3]);
+		if (!Number.isNaN(seconds)) {
+			const totalMs = ((hours * 60 + minutes) * 60 + seconds) * 1000;
+			const delay = normalizeDelay(totalMs);
+			if (delay !== undefined) {
+				return delay;
+			}
+		}
+	}
+
+	// Pattern 2: "Please retry in X[ms|s]"
+	const retryInMatch = errorText.match(/Please retry in ([0-9.]+)(ms|s)/i);
+	if (retryInMatch?.[1]) {
+		const value = parseFloat(retryInMatch[1]);
+		if (!Number.isNaN(value) && value > 0) {
+			const ms = retryInMatch[2].toLowerCase() === "ms" ? value : value * 1000;
+			const delay = normalizeDelay(ms);
+			if (delay !== undefined) {
+				return delay;
+			}
+		}
+	}
+
+	// Pattern 3: "retryDelay": "34.074824224s" (JSON field in error details)
+	const retryDelayMatch = errorText.match(/"retryDelay":\s*"([0-9.]+)(ms|s)"/i);
+	if (retryDelayMatch?.[1]) {
+		const value = parseFloat(retryDelayMatch[1]);
+		if (!Number.isNaN(value) && value > 0) {
+			const ms = retryDelayMatch[2].toLowerCase() === "ms" ? value : value * 1000;
+			const delay = normalizeDelay(ms);
+			if (delay !== undefined) {
+				return delay;
+			}
+		}
+	}
+
+	return undefined;
+}
+
+function needsClaudeThinkingBetaHeader(model: Model<"google-gemini-cli">): boolean {
+	return model.provider === "google-antigravity" && model.id.startsWith("claude-") && model.reasoning;
+}
+
+function isGemini3ProModel(modelId: string): boolean {
+	return /gemini-3(?:\.1)?-pro/.test(modelId.toLowerCase());
+}
+
+function isGemini3FlashModel(modelId: string): boolean {
+	return /gemini-3(?:\.1)?-flash/.test(modelId.toLowerCase());
+}
+
+function isGemini3Model(modelId: string): boolean {
+	return isGemini3ProModel(modelId) || isGemini3FlashModel(modelId);
+}
+
+/**
+ * Check if an error is retryable (rate limit, server error, network error, etc.)
+ */
+function isRetryableError(status: number, errorText: string): boolean {
+	if (status === 429 || status === 500 || status === 502 || status === 503 || status === 504) {
+		return true;
+	}
+	return /resource.?exhausted|rate.?limit|overloaded|service.?unavailable|other.?side.?closed/i.test(errorText);
+}
+
+/**
+ * Extract a clean, user-friendly error message from Google API error response.
+ * Parses JSON error responses and returns just the message field.
+ */
+function extractErrorMessage(errorText: string): string {
+	try {
+		const parsed = JSON.parse(errorText) as { error?: { message?: string } };
+		if (parsed.error?.message) {
+			return parsed.error.message;
+		}
+	} catch {
+		// Not JSON, return as-is
+	}
+	return errorText;
+}
+
+/**
+ * Sleep for a given number of milliseconds, respecting abort signal.
+ */
+function sleep(ms: number, signal?: AbortSignal): Promise<void> {
+	return new Promise((resolve, reject) => {
+		if (signal?.aborted) {
+			reject(new Error("Request was aborted"));
+			return;
+		}
+		const timeout = setTimeout(resolve, ms);
+		signal?.addEventListener("abort", () => {
+			clearTimeout(timeout);
+			reject(new Error("Request was aborted"));
+		});
+	});
+}
+
+interface CloudCodeAssistRequest {
+	project: string;
+	model: string;
+	request: {
+		contents: Content[];
+		sessionId?: string;
+		systemInstruction?: { role?: string; parts: { text: string }[] };
+		generationConfig?: {
+			maxOutputTokens?: number;
+			temperature?: number;
+			thinkingConfig?: ThinkingConfig;
+		};
+		tools?: ReturnType<typeof convertTools>;
+		toolConfig?: {
+			functionCallingConfig: {
+				mode: ReturnType<typeof mapToolChoice>;
+			};
+		};
+	};
+	requestType?: string;
+	userAgent?: string;
+	requestId?: string;
+}
+
+interface CloudCodeAssistResponseChunk {
+	response?: {
+		candidates?: Array<{
+			content?: {
+				role: string;
+				parts?: Array<{
+					text?: string;
+					thought?: boolean;
+					thoughtSignature?: string;
+					functionCall?: {
+						name: string;
+						args: Record<string, unknown>;
+						id?: string;
+					};
+				}>;
+			};
+			finishReason?: string;
+		}>;
+		usageMetadata?: {
+			promptTokenCount?: number;
+			candidatesTokenCount?: number;
+			thoughtsTokenCount?: number;
+			totalTokenCount?: number;
+			cachedContentTokenCount?: number;
+		};
+		modelVersion?: string;
+		responseId?: string;
+	};
+	traceId?: string;
+}
+
+export const streamGoogleGeminiCli: StreamFunction<"google-gemini-cli", GoogleGeminiCliOptions> = (
+	model: Model<"google-gemini-cli">,
+	context: Context,
+	options?: GoogleGeminiCliOptions,
+): AssistantMessageEventStream => {
+	const stream = new AssistantMessageEventStream();
+
+	(async () => {
+		const output: AssistantMessage = {
+			role: "assistant",
+			content: [],
+			api: "google-gemini-cli" as 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: "stop",
+			timestamp: Date.now(),
+		};
+
+		try {
+			// apiKey is JSON-encoded: { token, projectId }
+			const apiKeyRaw = options?.apiKey;
+			if (!apiKeyRaw) {
+				throw new Error("Google Cloud Code Assist requires OAuth authentication. Use /login to authenticate.");
+			}
+
+			let accessToken: string;
+			let projectId: string;
+
+			try {
+				const parsed = JSON.parse(apiKeyRaw) as { token: string; projectId: string };
+				accessToken = parsed.token;
+				projectId = parsed.projectId;
+			} catch {
+				throw new Error("Invalid Google Cloud Code Assist credentials. Use /login to re-authenticate.");
+			}
+
+			if (!accessToken || !projectId) {
+				throw new Error("Missing token or projectId in Google Cloud credentials. Use /login to re-authenticate.");
+			}
+
+			const isAntigravity = model.provider === "google-antigravity";
+			const baseUrl = model.baseUrl?.trim();
+			const endpoints = baseUrl ? [baseUrl] : isAntigravity ? ANTIGRAVITY_ENDPOINT_FALLBACKS : [DEFAULT_ENDPOINT];
+
+			let requestBody = buildRequest(model, context, projectId, options, isAntigravity);
+			const nextRequestBody = await options?.onPayload?.(requestBody, model);
+			if (nextRequestBody !== undefined) {
+				requestBody = nextRequestBody as CloudCodeAssistRequest;
+			}
+			const headers = isAntigravity ? getAntigravityHeaders() : GEMINI_CLI_HEADERS;
+
+			const requestHeaders = {
+				Authorization: `Bearer ${accessToken}`,
+				"Content-Type": "application/json",
+				Accept: "text/event-stream",
+				...headers,
+				...(needsClaudeThinkingBetaHeader(model) ? { "anthropic-beta": CLAUDE_THINKING_BETA_HEADER } : {}),
+				...options?.headers,
+			};
+			const requestBodyJson = JSON.stringify(requestBody);
+
+			// Fetch with retry logic for rate limits, transient errors, and endpoint fallbacks.
+			// On 403/404, immediately try the next endpoint (no delay).
+			// On 429/5xx, retry with backoff on the same or next endpoint.
+			let response: Response | undefined;
+			let lastError: Error | undefined;
+			let requestUrl: string | undefined;
+			let endpointIndex = 0;
+
+			for (let attempt = 0; attempt <= MAX_RETRIES; attempt++) {
+				if (options?.signal?.aborted) {
+					throw new Error("Request was aborted");
+				}
+
+				try {
+					const endpoint = endpoints[endpointIndex];
+					requestUrl = `${endpoint}/v1internal:streamGenerateContent?alt=sse`;
+					response = await fetch(requestUrl, {
+						method: "POST",
+						headers: requestHeaders,
+						body: requestBodyJson,
+						signal: options?.signal,
+					});
+
+					if (response.ok) {
+						break; // Success, exit retry loop
+					}
+
+					const errorText = await response.text();
+
+					// On 403/404, cascade to the next endpoint immediately (no delay)
+					if ((response.status === 403 || response.status === 404) && endpointIndex < endpoints.length - 1) {
+						endpointIndex++;
+						continue;
+					}
+
+					// Check if retryable (429, 5xx, network patterns)
+					if (attempt < MAX_RETRIES && isRetryableError(response.status, errorText)) {
+						// Advance endpoint if possible
+						if (endpointIndex < endpoints.length - 1) {
+							endpointIndex++;
+						}
+
+						// Use server-provided delay or exponential backoff
+						const serverDelay = extractRetryDelay(errorText, response);
+						const delayMs = serverDelay ?? BASE_DELAY_MS * 2 ** attempt;
+
+						// Check if server delay exceeds max allowed (default: 60s)
+						const maxDelayMs = options?.maxRetryDelayMs ?? 60000;
+						if (maxDelayMs > 0 && serverDelay && serverDelay > maxDelayMs) {
+							const delaySeconds = Math.ceil(serverDelay / 1000);
+							throw new Error(
+								`Server requested ${delaySeconds}s retry delay (max: ${Math.ceil(maxDelayMs / 1000)}s). ${extractErrorMessage(errorText)}`,
+							);
+						}
+
+						await sleep(delayMs, options?.signal);
+						continue;
+					}
+
+					// Not retryable or max retries exceeded
+					throw new Error(`Cloud Code Assist API error (${response.status}): ${extractErrorMessage(errorText)}`);
+				} catch (error) {
+					// Check for abort - fetch throws AbortError, our code throws "Request was aborted"
+					if (error instanceof Error) {
+						if (error.name === "AbortError" || error.message === "Request was aborted") {
+							throw new Error("Request was aborted");
+						}
+					}
+					// Extract detailed error message from fetch errors (Node includes cause)
+					lastError = error instanceof Error ? error : new Error(String(error));
+					if (lastError.message === "fetch failed" && lastError.cause instanceof Error) {
+						lastError = new Error(`Network error: ${lastError.cause.message}`);
+					}
+					// Network errors are retryable
+					if (attempt < MAX_RETRIES) {
+						const delayMs = BASE_DELAY_MS * 2 ** attempt;
+						await sleep(delayMs, options?.signal);
+						continue;
+					}
+					throw lastError;
+				}
+			}
+
+			if (!response || !response.ok) {
+				throw lastError ?? new Error("Failed to get response after retries");
+			}
+
+			let started = false;
+			const ensureStarted = () => {
+				if (!started) {
+					stream.push({ type: "start", partial: output });
+					started = true;
+				}
+			};
+
+			const resetOutput = () => {
+				output.content = [];
+				output.usage = {
+					input: 0,
+					output: 0,
+					cacheRead: 0,
+					cacheWrite: 0,
+					totalTokens: 0,
+					cost: { input: 0, output: 0, cacheRead: 0, cacheWrite: 0, total: 0 },
+				};
+				output.stopReason = "stop";
+				output.errorMessage = undefined;
+				output.timestamp = Date.now();
+				started = false;
+			};
+
+			const streamResponse = async (activeResponse: Response): Promise<boolean> => {
+				if (!activeResponse.body) {
+					throw new Error("No response body");
+				}
+
+				let hasContent = false;
+				let currentBlock: TextContent | ThinkingContent | null = null;
+				const blocks = output.content;
+				const blockIndex = () => blocks.length - 1;
+
+				// Read SSE stream
+				const reader = activeResponse.body.getReader();
+				const decoder = new TextDecoder();
+				let buffer = "";
+
+				// Set up abort handler to cancel reader when signal fires
+				const abortHandler = () => {
+					void reader.cancel().catch(() => {});
+				};
+				options?.signal?.addEventListener("abort", abortHandler);
+
+				try {
+					while (true) {
+						// Check abort signal before each read
+						if (options?.signal?.aborted) {
+							throw new Error("Request was aborted");
+						}
+
+						const { done, value } = await reader.read();
+						if (done) break;
+
+						buffer += decoder.decode(value, { stream: true });
+						const lines = buffer.split("\n");
+						buffer = lines.pop() || "";
+
+						for (const line of lines) {
+							if (!line.startsWith("data:")) continue;
+
+							const jsonStr = line.slice(5).trim();
+							if (!jsonStr) continue;
+
+							let chunk: CloudCodeAssistResponseChunk;
+							try {
+								chunk = JSON.parse(jsonStr);
+							} catch {
+								continue;
+							}
+
+							// Unwrap the response
+							const responseData = chunk.response;
+							if (!responseData) continue;
+							// Cloud Code Assist mirrors Gemini's responseId field. Keep the first non-empty one.
+							// A single streamed response should retain the same ID across chunks.
+							output.responseId ||= responseData.responseId;
+
+							const candidate = responseData.candidates?.[0];
+							if (candidate?.content?.parts) {
+								for (const part of candidate.content.parts) {
+									if (part.text !== undefined) {
+										hasContent = true;
+										const isThinking = isThinkingPart(part);
+										if (
+											!currentBlock ||
+											(isThinking && currentBlock.type !== "thinking") ||
+											(!isThinking && currentBlock.type !== "text")
+										) {
+											if (currentBlock) {
+												if (currentBlock.type === "text") {
+													stream.push({
+														type: "text_end",
+														contentIndex: blocks.length - 1,
+														content: currentBlock.text,
+														partial: output,
+													});
+												} else {
+													stream.push({
+														type: "thinking_end",
+														contentIndex: blockIndex(),
+														content: currentBlock.thinking,
+														partial: output,
+													});
+												}
+											}
+											if (isThinking) {
+												currentBlock = { type: "thinking", thinking: "", thinkingSignature: undefined };
+												output.content.push(currentBlock);
+												ensureStarted();
+												stream.push({
+													type: "thinking_start",
+													contentIndex: blockIndex(),
+													partial: output,
+												});
+											} else {
+												currentBlock = { type: "text", text: "" };
+												output.content.push(currentBlock);
+												ensureStarted();
+												stream.push({ type: "text_start", contentIndex: blockIndex(), partial: output });
+											}
+										}
+										if (currentBlock.type === "thinking") {
+											currentBlock.thinking += part.text;
+											currentBlock.thinkingSignature = retainThoughtSignature(
+												currentBlock.thinkingSignature,
+												part.thoughtSignature,
+											);
+											stream.push({
+												type: "thinking_delta",
+												contentIndex: blockIndex(),
+												delta: part.text,
+												partial: output,
+											});
+										} else {
+											currentBlock.text += part.text;
+											currentBlock.textSignature = retainThoughtSignature(
+												currentBlock.textSignature,
+												part.thoughtSignature,
+											);
+											stream.push({
+												type: "text_delta",
+												contentIndex: blockIndex(),
+												delta: part.text,
+												partial: output,
+											});
+										}
+									}
+
+									if (part.functionCall) {
+										hasContent = true;
+										if (currentBlock) {
+											if (currentBlock.type === "text") {
+												stream.push({
+													type: "text_end",
+													contentIndex: blockIndex(),
+													content: currentBlock.text,
+													partial: output,
+												});
+											} else {
+												stream.push({
+													type: "thinking_end",
+													contentIndex: blockIndex(),
+													content: currentBlock.thinking,
+													partial: output,
+												});
+											}
+											currentBlock = null;
+										}
+
+										const providedId = part.functionCall.id;
+										const needsNewId =
+											!providedId ||
+											output.content.some((b) => b.type === "toolCall" && b.id === providedId);
+										const toolCallId = needsNewId
+											? `${part.functionCall.name}_${Date.now()}_${++toolCallCounter}`
+											: providedId;
+
+										const toolCall: ToolCall = {
+											type: "toolCall",
+											id: toolCallId,
+											name: part.functionCall.name || "",
+											arguments: (part.functionCall.args as Record<string, unknown>) ?? {},
+											...(part.thoughtSignature && { thoughtSignature: part.thoughtSignature }),
+										};
+
+										output.content.push(toolCall);
+										ensureStarted();
+										stream.push({ type: "toolcall_start", contentIndex: blockIndex(), partial: output });
+										stream.push({
+											type: "toolcall_delta",
+											contentIndex: blockIndex(),
+											delta: JSON.stringify(toolCall.arguments),
+											partial: output,
+										});
+										stream.push({
+											type: "toolcall_end",
+											contentIndex: blockIndex(),
+											toolCall,
+											partial: output,
+										});
+									}
+								}
+							}
+
+							if (candidate?.finishReason) {
+								output.stopReason = mapStopReasonString(candidate.finishReason);
+								if (output.content.some((b) => b.type === "toolCall")) {
+									output.stopReason = "toolUse";
+								}
+							}
+
+							if (responseData.usageMetadata) {
+								// promptTokenCount includes cachedContentTokenCount, so subtract to get fresh input
+								const promptTokens = responseData.usageMetadata.promptTokenCount || 0;
+								const cacheReadTokens = responseData.usageMetadata.cachedContentTokenCount || 0;
+								output.usage = {
+									input: promptTokens - cacheReadTokens,
+									output:
+										(responseData.usageMetadata.candidatesTokenCount || 0) +
+										(responseData.usageMetadata.thoughtsTokenCount || 0),
+									cacheRead: cacheReadTokens,
+									cacheWrite: 0,
+									totalTokens: responseData.usageMetadata.totalTokenCount || 0,
+									cost: {
+										input: 0,
+										output: 0,
+										cacheRead: 0,
+										cacheWrite: 0,
+										total: 0,
+									},
+								};
+								calculateCost(model, output.usage);
+							}
+						}
+					}
+				} finally {
+					options?.signal?.removeEventListener("abort", abortHandler);
+				}
+
+				if (currentBlock) {
+					if (currentBlock.type === "text") {
+						stream.push({
+							type: "text_end",
+							contentIndex: blockIndex(),
+							content: currentBlock.text,
+							partial: output,
+						});
+					} else {
+						stream.push({
+							type: "thinking_end",
+							contentIndex: blockIndex(),
+							content: currentBlock.thinking,
+							partial: output,
+						});
+					}
+				}
+
+				return hasContent;
+			};
+
+			let receivedContent = false;
+			let currentResponse = response;
+
+			for (let emptyAttempt = 0; emptyAttempt <= MAX_EMPTY_STREAM_RETRIES; emptyAttempt++) {
+				if (options?.signal?.aborted) {
+					throw new Error("Request was aborted");
+				}
+
+				if (emptyAttempt > 0) {
+					const backoffMs = EMPTY_STREAM_BASE_DELAY_MS * 2 ** (emptyAttempt - 1);
+					await sleep(backoffMs, options?.signal);
+
+					if (!requestUrl) {
+						throw new Error("Missing request URL");
+					}
+
+					currentResponse = await fetch(requestUrl, {
+						method: "POST",
+						headers: requestHeaders,
+						body: requestBodyJson,
+						signal: options?.signal,
+					});
+
+					if (!currentResponse.ok) {
+						const retryErrorText = await currentResponse.text();
+						throw new Error(`Cloud Code Assist API error (${currentResponse.status}): ${retryErrorText}`);
+					}
+				}
+
+				const streamed = await streamResponse(currentResponse);
+				if (streamed) {
+					receivedContent = true;
+					break;
+				}
+
+				if (emptyAttempt < MAX_EMPTY_STREAM_RETRIES) {
+					resetOutput();
+				}
+			}
+
+			if (!receivedContent) {
+				throw new Error("Cloud Code Assist API returned an empty response");
+			}
+
+			if (options?.signal?.aborted) {
+				throw new Error("Request was aborted");
+			}
+
+			if (output.stopReason === "aborted" || output.stopReason === "error") {
+				throw new Error("An unknown error occurred");
+			}
+
+			stream.push({ type: "done", reason: output.stopReason, message: output });
+			stream.end();
+		} catch (error) {
+			for (const block of output.content) {
+				if ("index" in block) {
+					delete (block as { index?: number }).index;
+				}
+			}
+			output.stopReason = options?.signal?.aborted ? "aborted" : "error";
+			output.errorMessage = error instanceof Error ? error.message : JSON.stringify(error);
+			stream.push({ type: "error", reason: output.stopReason, error: output });
+			stream.end();
+		}
+	})();
+
+	return stream;
+};
+
+export const streamSimpleGoogleGeminiCli: StreamFunction<"google-gemini-cli", SimpleStreamOptions> = (
+	model: Model<"google-gemini-cli">,
+	context: Context,
+	options?: SimpleStreamOptions,
+): AssistantMessageEventStream => {
+	const apiKey = options?.apiKey;
+	if (!apiKey) {
+		throw new Error("Google Cloud Code Assist requires OAuth authentication. Use /login to authenticate.");
+	}
+
+	const base = buildBaseOptions(model, options, apiKey);
+	if (!options?.reasoning) {
+		return streamGoogleGeminiCli(model, context, {
+			...base,
+			thinking: { enabled: false },
+		} satisfies GoogleGeminiCliOptions);
+	}
+
+	const effort = clampReasoning(options.reasoning)!;
+	if (isGemini3Model(model.id)) {
+		return streamGoogleGeminiCli(model, context, {
+			...base,
+			thinking: {
+				enabled: true,
+				level: getGeminiCliThinkingLevel(effort, model.id),
+			},
+		} satisfies GoogleGeminiCliOptions);
+	}
+
+	const defaultBudgets: ThinkingBudgets = {
+		minimal: 1024,
+		low: 2048,
+		medium: 8192,
+		high: 16384,
+	};
+	const budgets = { ...defaultBudgets, ...options.thinkingBudgets };
+
+	const minOutputTokens = 1024;
+	let thinkingBudget = budgets[effort]!;
+	const maxTokens = Math.min((base.maxTokens || 0) + thinkingBudget, model.maxTokens);
+
+	if (maxTokens <= thinkingBudget) {
+		thinkingBudget = Math.max(0, maxTokens - minOutputTokens);
+	}
+
+	return streamGoogleGeminiCli(model, context, {
+		...base,
+		maxTokens,
+		thinking: {
+			enabled: true,
+			budgetTokens: thinkingBudget,
+		},
+	} satisfies GoogleGeminiCliOptions);
+};
+
+export function buildRequest(
+	model: Model<"google-gemini-cli">,
+	context: Context,
+	projectId: string,
+	options: GoogleGeminiCliOptions = {},
+	isAntigravity = false,
+): CloudCodeAssistRequest {
+	const contents = convertMessages(model, context);
+
+	const generationConfig: CloudCodeAssistRequest["request"]["generationConfig"] = {};
+	if (options.temperature !== undefined) {
+		generationConfig.temperature = options.temperature;
+	}
+	if (options.maxTokens !== undefined) {
+		generationConfig.maxOutputTokens = options.maxTokens;
+	}
+
+	// Thinking config
+	if (options.thinking?.enabled && model.reasoning) {
+		generationConfig.thinkingConfig = {
+			includeThoughts: true,
+		};
+		// Gemini 3 models use thinkingLevel, older models use thinkingBudget
+		if (options.thinking.level !== undefined) {
+			// Cast to any since our GoogleThinkingLevel mirrors Google's ThinkingLevel enum values
+			generationConfig.thinkingConfig.thinkingLevel = options.thinking.level as any;
+		} else if (options.thinking.budgetTokens !== undefined) {
+			generationConfig.thinkingConfig.thinkingBudget = options.thinking.budgetTokens;
+		}
+	} else if (model.reasoning && options.thinking && !options.thinking.enabled) {
+		generationConfig.thinkingConfig = getDisabledThinkingConfig(model.id);
+	}
+
+	const request: CloudCodeAssistRequest["request"] = {
+		contents,
+	};
+
+	request.sessionId = options.sessionId;
+
+	// System instruction must be object with parts, not plain string
+	if (context.systemPrompt) {
+		request.systemInstruction = {
+			parts: [{ text: sanitizeSurrogates(context.systemPrompt) }],
+		};
+	}
+
+	if (Object.keys(generationConfig).length > 0) {
+		request.generationConfig = generationConfig;
+	}
+
+	if (context.tools && context.tools.length > 0) {
+		// 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: {
+					mode: mapToolChoice(options.toolChoice),
+				},
+			};
+		}
+	}
+
+	if (isAntigravity) {
+		const existingParts = request.systemInstruction?.parts ?? [];
+		request.systemInstruction = {
+			role: "user",
+			parts: [
+				{ text: ANTIGRAVITY_SYSTEM_INSTRUCTION },
+				{ text: `Please ignore following [ignore]${ANTIGRAVITY_SYSTEM_INSTRUCTION}[/ignore]` },
+				...existingParts,
+			],
+		};
+	}
+
+	return {
+		project: projectId,
+		model: model.id,
+		request,
+		...(isAntigravity ? { requestType: "agent" } : {}),
+		userAgent: isAntigravity ? "antigravity" : "pi-coding-agent",
+		requestId: `${isAntigravity ? "agent" : "pi"}-${Date.now()}-${Math.random().toString(36).slice(2, 11)}`,
+	};
+}
+
+type ClampedThinkingLevel = Exclude<ThinkingLevel, "xhigh">;
+
+function getDisabledThinkingConfig(modelId: string): ThinkingConfig {
+	// Google docs: Gemini 3.1 Pro cannot disable thinking, and Gemini 3 Flash / Flash-Lite
+	// do not support full thinking-off either. For Gemini 3 models, use the lowest supported
+	// thinkingLevel without includeThoughts so hidden thinking remains invisible to pi.
+	if (isGemini3ProModel(modelId)) {
+		return { thinkingLevel: "LOW" as any };
+	}
+	if (isGemini3FlashModel(modelId)) {
+		return { thinkingLevel: "MINIMAL" as any };
+	}
+
+	// Gemini 2.x supports disabling via thinkingBudget = 0.
+	return { thinkingBudget: 0 };
+}
+
+function getGeminiCliThinkingLevel(effort: ClampedThinkingLevel, modelId: string): GoogleThinkingLevel {
+	if (isGemini3ProModel(modelId)) {
+		switch (effort) {
+			case "minimal":
+			case "low":
+				return "LOW";
+			case "medium":
+			case "high":
+				return "HIGH";
+		}
+	}
+	switch (effort) {
+		case "minimal":
+			return "MINIMAL";
+		case "low":
+			return "LOW";
+		case "medium":
+			return "MEDIUM";
+		case "high":
+			return "HIGH";
+	}
+}