diff --git a/src/resources/extensions/google-search/index.ts b/src/resources/extensions/google-search/index.ts
new file mode 100644
index 000000000..66586325c
--- /dev/null
+++ b/src/resources/extensions/google-search/index.ts
@@ -0,0 +1,323 @@
+/**
+ * Google Search Extension
+ *
+ * Provides a `google_search` tool that performs web searches via Gemini's
+ * Google Search grounding feature. Uses the user's existing GEMINI_API_KEY
+ * and Google Cloud GenAI credits.
+ *
+ * The tool sends queries to Gemini Flash with `googleSearch: {}` enabled.
+ * Gemini internally performs Google searches, synthesizes an answer, and
+ * returns it with source URLs from grounding metadata.
+ */
+
+import type { ExtensionAPI } from "@mariozechner/pi-coding-agent";
+import {
+	DEFAULT_MAX_BYTES,
+	DEFAULT_MAX_LINES,
+	formatSize,
+	truncateHead,
+} from "@mariozechner/pi-coding-agent";
+import { Text } from "@mariozechner/pi-tui";
+import { Type } from "@sinclair/typebox";
+import { GoogleGenAI } from "@google/genai";
+
+// ── Types ────────────────────────────────────────────────────────────────────
+
+interface SearchSource {
+	title: string;
+	uri: string;
+	domain: string;
+}
+
+interface SearchResult {
+	answer: string;
+	sources: SearchSource[];
+	searchQueries: string[];
+	cached: boolean;
+}
+
+interface SearchDetails {
+	query: string;
+	sourceCount: number;
+	cached: boolean;
+	durationMs: number;
+	error?: string;
+}
+
+// ── Lazy singleton client ────────────────────────────────────────────────────
+
+let client: GoogleGenAI | null = null;
+
+function getClient(): GoogleGenAI {
+	if (!client) {
+		client = new GoogleGenAI({ apiKey: process.env.GEMINI_API_KEY! });
+	}
+	return client;
+}
+
+// ── In-session cache ─────────────────────────────────────────────────────────
+
+const resultCache = new Map<string, SearchResult>();
+
+function cacheKey(query: string): string {
+	return query.toLowerCase().trim();
+}
+
+// ── Extension ────────────────────────────────────────────────────────────────
+
+export default function (pi: ExtensionAPI) {
+	pi.registerTool({
+		name: "google_search",
+		label: "Google Search",
+		description:
+			"Search the web using Google Search via Gemini. " +
+			"Returns an AI-synthesized answer grounded in Google Search results, plus source URLs. " +
+			"Use this when you need current information from the web: recent events, documentation, " +
+			"product details, technical references, news, etc. " +
+			"Requires GEMINI_API_KEY. Alternative to Brave-based search tools for users with Google Cloud credits.",
+		promptSnippet: "Search the web via Google Search to get current information with sources",
+		promptGuidelines: [
+			"Use google_search when you need up-to-date web information that isn't in your training data.",
+			"Be specific with queries for better results, e.g. 'Next.js 15 app router migration guide' not just 'Next.js'.",
+			"The tool returns both an answer and source URLs. Cite sources when sharing results with the user.",
+			"Results are cached per-session, so repeated identical queries are free.",
+			"You can still use fetch_page to read a specific URL if needed after getting results from google_search.",
+		],
+		parameters: Type.Object({
+			query: Type.String({
+				description: "The search query, e.g. 'latest Node.js LTS version' or 'how to configure Tailwind v4'",
+			}),
+			maxSources: Type.Optional(
+				Type.Number({
+					description: "Maximum number of source URLs to include (default 5, max 10).",
+					minimum: 1,
+					maximum: 10,
+				}),
+			),
+		}),
+
+		async execute(_toolCallId, params, signal, _onUpdate, _ctx) {
+			const startTime = Date.now();
+			const maxSources = Math.min(Math.max(params.maxSources ?? 5, 1), 10);
+
+			// Check for API key
+			if (!process.env.GEMINI_API_KEY) {
+				return {
+					content: [
+						{
+							type: "text",
+							text: "Error: GEMINI_API_KEY is not set. Please set this environment variable to use Google Search.\n\nExample: export GEMINI_API_KEY=your_key",
+						},
+					],
+					isError: true,
+					details: {
+						query: params.query,
+						sourceCount: 0,
+						cached: false,
+						durationMs: Date.now() - startTime,
+						error: "auth_error: GEMINI_API_KEY not set",
+					} as SearchDetails,
+				};
+			}
+
+			// Check cache
+			const key = cacheKey(params.query);
+			if (resultCache.has(key)) {
+				const cached = resultCache.get(key)!;
+				const output = formatOutput(cached, maxSources);
+				return {
+					content: [{ type: "text", text: output }],
+					details: {
+						query: params.query,
+						sourceCount: cached.sources.length,
+						cached: true,
+						durationMs: Date.now() - startTime,
+					} as SearchDetails,
+				};
+			}
+
+			// Call Gemini with Google Search grounding
+			let result: SearchResult;
+			try {
+				const ai = getClient();
+				const response = await ai.models.generateContent({
+					model: "gemini-3-flash-preview",
+					contents: params.query,
+					config: {
+						tools: [{ googleSearch: {} }],
+						abortSignal: signal,
+					},
+				});
+
+				// Extract answer text
+				const answer = response.text ?? "";
+
+				// Extract grounding metadata
+				const candidate = response.candidates?.[0];
+				const grounding = candidate?.groundingMetadata;
+
+				// Parse sources from grounding chunks
+				const sources: SearchSource[] = [];
+				const seenTitles = new Set<string>();
+				if (grounding?.groundingChunks) {
+					for (const chunk of grounding.groundingChunks) {
+						if (chunk.web) {
+							const title = chunk.web.title ?? "Untitled";
+							// Dedupe by title since URIs are redirect URLs that differ per call
+							if (seenTitles.has(title)) continue;
+							seenTitles.add(title);
+							// domain field is not available via Gemini API, use title as fallback
+							// (title is typically the domain name, e.g. "wikipedia.org")
+							const domain = chunk.web.domain ?? title;
+							sources.push({
+								title,
+								uri: chunk.web.uri ?? "",
+								domain,
+							});
+						}
+					}
+				}
+
+				// Extract search queries Gemini actually performed
+				const searchQueries = grounding?.webSearchQueries ?? [];
+
+				result = { answer, sources, searchQueries, cached: false };
+			} catch (err: unknown) {
+				const msg = err instanceof Error ? err.message : String(err);
+
+				let errorType = "api_error";
+				if (msg.includes("401") || msg.includes("UNAUTHENTICATED")) {
+					errorType = "auth_error";
+				} else if (msg.includes("429") || msg.includes("RESOURCE_EXHAUSTED") || msg.includes("quota")) {
+					errorType = "rate_limit";
+				}
+
+				return {
+					content: [
+						{
+							type: "text",
+							text: `Google Search failed (${errorType}): ${msg}`,
+						},
+					],
+					isError: true,
+					details: {
+						query: params.query,
+						sourceCount: 0,
+						cached: false,
+						durationMs: Date.now() - startTime,
+						error: `${errorType}: ${msg}`,
+					} as SearchDetails,
+				};
+			}
+
+			// Cache the result
+			resultCache.set(key, result);
+
+			// Format and truncate output
+			const rawOutput = formatOutput(result, maxSources);
+			const truncation = truncateHead(rawOutput, {
+				maxLines: DEFAULT_MAX_LINES,
+				maxBytes: DEFAULT_MAX_BYTES,
+			});
+
+			let finalText = truncation.content;
+			if (truncation.truncated) {
+				finalText +=
+					`\n\n[Truncated: showing ${truncation.outputLines}/${truncation.totalLines} lines` +
+					` (${formatSize(truncation.outputBytes)} of ${formatSize(truncation.totalBytes)})]`;
+			}
+
+			return {
+				content: [{ type: "text", text: finalText }],
+				details: {
+					query: params.query,
+					sourceCount: result.sources.length,
+					cached: false,
+					durationMs: Date.now() - startTime,
+				} as SearchDetails,
+			};
+		},
+
+		renderCall(args, theme) {
+			let text = theme.fg("toolTitle", theme.bold("google_search "));
+			text += theme.fg("accent", `"${args.query}"`);
+			return new Text(text, 0, 0);
+		},
+
+		renderResult(result, { isPartial, expanded }, theme) {
+			const d = result.details as SearchDetails | undefined;
+
+			if (isPartial) return new Text(theme.fg("warning", "Searching Google..."), 0, 0);
+			if (result.isError || d?.error) {
+				return new Text(theme.fg("error", `Error: ${d?.error ?? "unknown"}`), 0, 0);
+			}
+
+			let text = theme.fg("success", `${d?.sourceCount ?? 0} sources`);
+			text += theme.fg("dim", ` (${d?.durationMs ?? 0}ms)`);
+			if (d?.cached) text += theme.fg("dim", " · cached");
+
+			if (expanded) {
+				const content = result.content[0];
+				if (content?.type === "text") {
+					const preview = content.text.split("\n").slice(0, 8).join("\n");
+					text += "\n\n" + theme.fg("dim", preview);
+					if (content.text.split("\n").length > 8) {
+						text += "\n" + theme.fg("muted", "...");
+					}
+				}
+			}
+
+			return new Text(text, 0, 0);
+		},
+	});
+
+	// ── Startup notification ─────────────────────────────────────────────────
+
+	pi.on("session_start", async (_event, ctx) => {
+		if (!process.env.GEMINI_API_KEY) {
+			ctx.ui.notify(
+				"Google Search: No GEMINI_API_KEY set. The google_search tool will not work until this is configured.",
+				"warning",
+			);
+		}
+	});
+}
+
+// ── Output formatting ────────────────────────────────────────────────────────
+
+function formatOutput(result: SearchResult, maxSources: number): string {
+	const lines: string[] = [];
+
+	// Answer
+	if (result.answer) {
+		lines.push(result.answer);
+	} else {
+		lines.push("(No answer text returned from search)");
+	}
+
+	// Sources
+	if (result.sources.length > 0) {
+		lines.push("");
+		lines.push("Sources:");
+		const sourcesToShow = result.sources.slice(0, maxSources);
+		for (let i = 0; i < sourcesToShow.length; i++) {
+			const s = sourcesToShow[i];
+			lines.push(`[${i + 1}] ${s.title} - ${s.domain}`);
+			lines.push(`    ${s.uri}`);
+		}
+		if (result.sources.length > maxSources) {
+			lines.push(`(${result.sources.length - maxSources} more sources omitted)`);
+		}
+	} else {
+		lines.push("");
+		lines.push("(No source URLs found in grounding metadata)");
+	}
+
+	// Search queries
+	if (result.searchQueries.length > 0) {
+		lines.push("");
+		lines.push(`Searches performed: ${result.searchQueries.map((q) => `"${q}"`).join(", ")}`);
+	}
+
+	return lines.join("\n");
+}
diff --git a/src/resources/extensions/google-search/package.json b/src/resources/extensions/google-search/package.json
new file mode 100644
index 000000000..6375e1c43
--- /dev/null
+++ b/src/resources/extensions/google-search/package.json
@@ -0,0 +1,9 @@
+{
+  "name": "pi-extension-google-search",
+  "private": true,
+  "version": "1.0.0",
+  "type": "module",
+  "pi": {
+    "extensions": ["./index.ts"]
+  }
+}