From 17eaaaf73e419dcd0dab95045fc6e6d3f6998591 Mon Sep 17 00:00:00 2001
From: Luis Esteban Acevedo Ladino <luis@Luiss-MacBook-Pro.local>
Date: Fri, 24 Apr 2026 07:25:04 -0500
Subject: [PATCH] feat: add native gemini provider

---
 apps/web/.env.example                         |   6 +
 apps/web/package.json                         |   1 +
 .../src/agent/__tests__/system-prompt.test.ts |  40 ++
 .../agent/providers/__tests__/gemini.test.ts  | 502 ++++++++++++++++++
 .../agent/providers/__tests__/index.test.ts   |  12 +
 apps/web/src/agent/providers/gemini.ts        | 240 +++++++++
 apps/web/src/agent/providers/index.ts         |   3 +
 apps/web/src/agent/system-prompt.ts           |   8 +-
 .../tools/__tests__/transcribe-video.test.ts  | 140 ++++-
 .../src/agent/tools/transcribe-video.tool.ts  |  35 +-
 bun.lock                                      |   3 +
 .../archive-report.md                         |  59 ++
 .../design.md                                 | 155 ++++++
 .../exploration.md                            |   0
 .../proposal.md                               |  65 +++
 .../specs/agent-session-shell/spec.md         |  97 ++++
 .../2026-04-24-gemini-adapter-fase-1/tasks.md |  28 +
 .../verify-report.md                          | 116 ++++
 openspec/specs/agent-session-shell/spec.md    |  68 ++-
 19 files changed, 1572 insertions(+), 6 deletions(-)
 create mode 100644 apps/web/src/agent/providers/__tests__/gemini.test.ts
 create mode 100644 apps/web/src/agent/providers/gemini.ts
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/archive-report.md
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/design.md
 rename openspec/changes/{gemini-adapter-fase-1 => archive/2026-04-24-gemini-adapter-fase-1}/exploration.md (100%)
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/proposal.md
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/specs/agent-session-shell/spec.md
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/tasks.md
 create mode 100644 openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/verify-report.md

diff --git a/apps/web/.env.example b/apps/web/.env.example
index 77ed9805..c5b16905 100644
--- a/apps/web/.env.example
+++ b/apps/web/.env.example
@@ -25,3 +25,9 @@ LLM_PROVIDER=openai-compatible
 LLM_API_KEY=your_openai_api_key_here
 LLM_MODEL=gpt-4o
 # LLM_BASE_URL=https://api.openai.com/v1
+
+# Gemini provider (set LLM_PROVIDER=gemini to activate)
+# LLM_PROVIDER=gemini
+# LLM_API_KEY=your_gemini_api_key_here
+# LLM_MODEL=gemini-2.0-flash
+# Note: LLM_BASE_URL is ignored when using the gemini provider
diff --git a/apps/web/package.json b/apps/web/package.json
index 0b8a704d..b8f38950 100644
--- a/apps/web/package.json
+++ b/apps/web/package.json
@@ -42,6 +42,7 @@
     "cmdk": "^1.0.0",
     "culori": "^4.0.2",
     "drizzle-orm": "^0.44.2",
+    "@google/generative-ai": "^0.24.0",
     "embla-carousel-react": "^8.5.1",
     "eventemitter3": "^5.0.1",
     "feed": "^5.1.0",
diff --git a/apps/web/src/agent/__tests__/system-prompt.test.ts b/apps/web/src/agent/__tests__/system-prompt.test.ts
index 5c83fe82..b20d2b2a 100644
--- a/apps/web/src/agent/__tests__/system-prompt.test.ts
+++ b/apps/web/src/agent/__tests__/system-prompt.test.ts
@@ -37,6 +37,46 @@ describe("buildSystemPrompt", () => {
 		expect(prompt).toContain("NeuralCut video editor");
 	});
 
+	test("includes asset internal id in media listing", () => {
+		const context: AgentContext = {
+			projectId: "proj-1",
+			activeSceneId: "scene-A",
+			mediaAssets: [
+				{ id: "m1", name: "intro.mp4", type: "video", duration: 30 },
+			],
+			playbackTimeMs: 0,
+		};
+
+		const prompt = buildSystemPrompt(context);
+
+		expect(prompt).toContain("[id: m1]");
+	});
+
+	test("includes assetId instruction when media assets are present", () => {
+		const context: AgentContext = {
+			projectId: "proj-1",
+			activeSceneId: "scene-A",
+			mediaAssets: [
+				{ id: "m1", name: "conclu.mov", type: "video", duration: 60 },
+			],
+			playbackTimeMs: 0,
+		};
+
+		const prompt = buildSystemPrompt(context);
+
+		expect(prompt).toContain("IMPORTANT");
+		expect(prompt).toContain("assetId");
+		expect(prompt).toContain('internal "id" value');
+		expect(prompt).toContain("NOT the filename");
+	});
+
+	test("omits assetId instruction when no media assets", () => {
+		const prompt = buildSystemPrompt(BASE_CONTEXT);
+
+		expect(prompt).not.toContain("IMPORTANT");
+		expect(prompt).not.toContain("assetId");
+	});
+
 	test("is valid when no media assets are loaded", () => {
 		const context: AgentContext = {
 			projectId: "proj-2",
diff --git a/apps/web/src/agent/providers/__tests__/gemini.test.ts b/apps/web/src/agent/providers/__tests__/gemini.test.ts
new file mode 100644
index 00000000..8e5cd3be
--- /dev/null
+++ b/apps/web/src/agent/providers/__tests__/gemini.test.ts
@@ -0,0 +1,502 @@
+import { beforeEach, describe, expect, jest, test } from "bun:test";
+import { SchemaType, type GenerateContentResult } from "@google/generative-ai";
+import type { ProviderConfig } from "@/agent/providers/types";
+import type { ToolSchema } from "@/agent/types";
+
+// ---------------------------------------------------------------------------
+// Mock the Google Generative AI SDK before the adapter module loads
+// ---------------------------------------------------------------------------
+
+const mockGenerateContent = jest.fn();
+
+jest.mock("@google/generative-ai", () => ({
+	GoogleGenerativeAI: class MockGoogleGenerativeAI {
+		getGenerativeModel(_opts: { model: string }) {
+			return { generateContent: mockGenerateContent };
+		}
+		constructor(_opts: { apiKey: string }) {}
+	},
+	SchemaType: {
+		STRING: "string",
+		NUMBER: "number",
+		BOOLEAN: "boolean",
+		OBJECT: "object",
+	},
+}));
+
+// Import after mock is set up
+import {
+	GeminiAdapter,
+	toGeminiContents,
+	toGeminiTools,
+	fromGeminiResponse,
+} from "@/agent/providers/gemini";
+
+// ---------------------------------------------------------------------------
+// Helpers
+// ---------------------------------------------------------------------------
+
+const TEST_CONFIG: ProviderConfig = {
+	provider: "gemini",
+	apiKey: "test-gemini-key",
+	model: "gemini-2.0-flash",
+};
+
+const SAMPLE_TOOLS: ToolSchema[] = [
+	{
+		name: "transcribe_video",
+		description: "Transcribes a video asset",
+		parameters: [
+			{ key: "assetId", type: "string", required: true },
+			{ key: "language", type: "string", required: false },
+		],
+	},
+];
+
+function makeGeminiResponse(overrides: {
+	text?: string;
+	functionCalls?: Array<{ name: string; args: Record<string, unknown> }>;
+}): GenerateContentResult {
+	const parts: Array<Record<string, unknown>> = [];
+
+	if (overrides.text !== undefined) {
+		parts.push({ text: overrides.text });
+	}
+
+	if (overrides.functionCalls) {
+		for (const fc of overrides.functionCalls) {
+			parts.push({ functionCall: { name: fc.name, args: fc.args } });
+		}
+	}
+
+	return {
+		response: {
+			candidates: [
+				{
+					content: { parts },
+				},
+			],
+		},
+	} as unknown as GenerateContentResult;
+}
+
+function makeChatMessage(
+	role: "user" | "assistant" | "system" | "tool_result",
+	content: string,
+	extra?: Record<string, unknown>,
+) {
+	return {
+		id: `msg-${Math.random().toString(36).slice(2)}`,
+		role,
+		content,
+		timestamp: Date.now(),
+		...extra,
+	};
+}
+
+// ---------------------------------------------------------------------------
+// Tests: toGeminiContents (Task 4.1)
+// ---------------------------------------------------------------------------
+
+describe("toGeminiContents", () => {
+	test("maps user message to Gemini user role", () => {
+		const messages = [makeChatMessage("user", "Hello")];
+		const contents = toGeminiContents(messages);
+
+		expect(contents).toHaveLength(1);
+		expect(contents[0].role).toBe("user");
+		expect(contents[0].parts).toEqual([{ text: "Hello" }]);
+	});
+
+	test("maps assistant message to Gemini model role", () => {
+		const messages = [makeChatMessage("assistant", "Hi there!")];
+		const contents = toGeminiContents(messages);
+
+		expect(contents).toHaveLength(1);
+		expect(contents[0].role).toBe("model");
+		expect(contents[0].parts).toEqual([{ text: "Hi there!" }]);
+	});
+
+	test("maps assistant with toolCalls to model role with functionCall parts", () => {
+		const messages = [
+			makeChatMessage("assistant", "Let me check.", {
+				toolCalls: [
+					{
+						id: "tc_1",
+						name: "transcribe_video",
+						args: { assetId: "vid-123" },
+					},
+				],
+			}),
+		];
+		const contents = toGeminiContents(messages);
+
+		expect(contents).toHaveLength(1);
+		expect(contents[0].role).toBe("model");
+		expect(contents[0].parts).toEqual([
+			{ text: "Let me check." },
+			{
+				functionCall: {
+					name: "transcribe_video",
+					args: { assetId: "vid-123" },
+				},
+			},
+		]);
+	});
+
+	test("maps tool_result to function role with functionResponse", () => {
+		const messages = [
+			makeChatMessage("assistant", "", {
+				toolCalls: [
+					{
+						id: "tc_1",
+						name: "transcribe_video",
+						args: { assetId: "vid-123" },
+					},
+				],
+			}),
+			makeChatMessage("tool_result", '{"transcript": "Hello world"}', {
+				toolCallId: "tc_1",
+			}),
+		];
+		const contents = toGeminiContents(messages);
+
+		// First: model (assistant with toolCalls)
+		expect(contents[0].role).toBe("model");
+		// Second: function (tool_result)
+		expect(contents[1].role).toBe("function");
+		expect(contents[1].parts).toEqual([
+			{
+				functionResponse: {
+					name: "transcribe_video",
+					response: { transcript: "Hello world" },
+				},
+			},
+		]);
+	});
+
+	test("excludes system messages from contents", () => {
+		const messages = [
+			makeChatMessage("system", "You are a video editor."),
+			makeChatMessage("user", "Hello"),
+		];
+		const contents = toGeminiContents(messages);
+
+		expect(contents).toHaveLength(1);
+		expect(contents[0].role).toBe("user");
+	});
+
+	test("handles tool_result with non-JSON content by wrapping in object", () => {
+		const messages = [
+			makeChatMessage("assistant", "", {
+				toolCalls: [
+					{ id: "tc_1", name: "some_tool", args: {} },
+				],
+			}),
+			makeChatMessage("tool_result", "plain text result", {
+				toolCallId: "tc_1",
+			}),
+		];
+		const contents = toGeminiContents(messages);
+
+		expect(contents[1].parts).toEqual([
+			{
+				functionResponse: {
+					name: "some_tool",
+					response: { result: "plain text result" },
+				},
+			},
+		]);
+	});
+});
+
+// ---------------------------------------------------------------------------
+// Tests: toGeminiTools (Task 4.2)
+// ---------------------------------------------------------------------------
+
+describe("toGeminiTools", () => {
+	test("converts a single tool with parameters", () => {
+		const declarations = toGeminiTools(SAMPLE_TOOLS);
+
+		expect(declarations).toHaveLength(1);
+		expect(declarations[0].name).toBe("transcribe_video");
+		expect(declarations[0].description).toBe("Transcribes a video asset");
+		expect(declarations[0].parameters?.type).toBe(SchemaType.OBJECT);
+		expect(declarations[0].parameters?.properties).toHaveProperty("assetId");
+		expect(declarations[0].parameters?.required).toEqual(["assetId"]);
+	});
+
+	test("maps type strings to Gemini SchemaType values", () => {
+		const tools: ToolSchema[] = [
+			{
+				name: "multi_param_tool",
+				description: "Tool with all param types",
+				parameters: [
+					{ key: "name", type: "string", required: true },
+					{ key: "count", type: "number", required: false },
+					{ key: "active", type: "boolean", required: false },
+					{ key: "meta", type: "object", required: false },
+				],
+			},
+		];
+
+		const declarations = toGeminiTools(tools);
+		const props = declarations[0].parameters?.properties as Record<
+			string,
+			{ type: string }
+		>;
+
+		expect(props.name.type).toBe(SchemaType.STRING);
+		expect(props.count.type).toBe(SchemaType.NUMBER);
+		expect(props.active.type).toBe(SchemaType.BOOLEAN);
+		expect(props.meta.type).toBe(SchemaType.OBJECT);
+	});
+
+	test("returns empty array when no tools provided", () => {
+		expect(toGeminiTools([])).toEqual([]);
+	});
+});
+
+// ---------------------------------------------------------------------------
+// Tests: fromGeminiResponse (Task 4.3)
+// ---------------------------------------------------------------------------
+
+describe("fromGeminiResponse", () => {
+	test("extracts text-only response with no toolCalls", () => {
+		const response = makeGeminiResponse({ text: "Hello from Gemini!" });
+		const result = fromGeminiResponse(response);
+
+		expect(result.content).toBe("Hello from Gemini!");
+		expect(result.toolCalls).toBeUndefined();
+	});
+
+	test("maps function-call response to toolCalls with non-empty synthesized IDs", () => {
+		const response = makeGeminiResponse({
+			text: undefined,
+			functionCalls: [
+				{ name: "transcribe_video", args: { assetId: "vid-1" } },
+			],
+		});
+		const result = fromGeminiResponse(response);
+
+		expect(result.content).toBe("");
+		expect(result.toolCalls).toHaveLength(1);
+		expect(result.toolCalls?.[0].name).toBe("transcribe_video");
+		expect(result.toolCalls?.[0].args).toEqual({ assetId: "vid-1" });
+		// Non-empty synthesized ID
+		expect(result.toolCalls?.[0].id).toBeTruthy();
+		expect(typeof result.toolCalls?.[0].id).toBe("string");
+	});
+
+	test("two calls produce different IDs", () => {
+		const response1 = makeGeminiResponse({
+			functionCalls: [{ name: "tool_a", args: {} }],
+		});
+		const response2 = makeGeminiResponse({
+			functionCalls: [{ name: "tool_a", args: {} }],
+		});
+
+		const result1 = fromGeminiResponse(response1);
+		const result2 = fromGeminiResponse(response2);
+
+		expect(result1.toolCalls?.[0].id).not.toBe(
+			result2.toolCalls?.[0].id,
+		);
+	});
+
+	test("handles mixed text and function-call parts", () => {
+		const response = makeGeminiResponse({
+			text: "I'll look that up.",
+			functionCalls: [{ name: "search", args: { q: "test" } }],
+		});
+		const result = fromGeminiResponse(response);
+
+		expect(result.content).toBe("I'll look that up.");
+		expect(result.toolCalls).toHaveLength(1);
+	});
+});
+
+// ---------------------------------------------------------------------------
+// Tests: error paths (Task 4.4)
+// ---------------------------------------------------------------------------
+
+describe("error paths", () => {
+	test("throws on empty candidates", () => {
+		const response = {
+			response: { candidates: [] },
+		};
+
+		expect(() => fromGeminiResponse(response as any)).toThrow(
+			"Empty response from Gemini provider",
+		);
+	});
+
+	test("throws on null candidates", () => {
+		const response = {
+			response: { candidates: null },
+		};
+
+		expect(() => fromGeminiResponse(response as any)).toThrow(
+			"Empty response from Gemini provider",
+		);
+	});
+
+	test("SDK error propagates from chat()", async () => {
+		mockGenerateContent.mockRejectedValueOnce(
+			new Error("API key not valid"),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+
+		expect(
+			adapter.chat({
+				messages: [makeChatMessage("user", "Hello")],
+				systemPrompt: "",
+				tools: [],
+			}),
+		).rejects.toThrow("API key not valid");
+	});
+});
+
+// ---------------------------------------------------------------------------
+// Tests: full chat() round-trip (Task 4.6)
+// ---------------------------------------------------------------------------
+
+describe("GeminiAdapter.chat()", () => {
+	beforeEach(() => {
+		mockGenerateContent.mockReset();
+	});
+
+	test("calls generateContent with correct contents and no tools", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({ text: "Hi!" }),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+		const result = await adapter.chat({
+			messages: [makeChatMessage("user", "Hello")],
+			systemPrompt: "You are helpful.",
+			tools: [],
+		});
+
+		expect(result.content).toBe("Hi!");
+		expect(result.toolCalls).toBeUndefined();
+
+		const callArgs = mockGenerateContent.mock.calls[0][0];
+		expect(callArgs.contents).toHaveLength(1);
+		expect(callArgs.contents[0].role).toBe("user");
+		expect(callArgs.systemInstruction).toBe("You are helpful.");
+		expect(callArgs.tools).toBeUndefined();
+	});
+
+	test("calls generateContent with tools and systemInstruction", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({
+				functionCalls: [
+					{
+						name: "transcribe_video",
+						args: { assetId: "vid-1" },
+					},
+				],
+			}),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+		const result = await adapter.chat({
+			messages: [makeChatMessage("user", "Transcribe this")],
+			systemPrompt: "Video editing assistant",
+			tools: SAMPLE_TOOLS,
+		});
+
+		expect(result.toolCalls).toHaveLength(1);
+		expect(result.toolCalls?.[0].name).toBe("transcribe_video");
+
+		const callArgs = mockGenerateContent.mock.calls[0][0];
+		expect(callArgs.systemInstruction).toBe("Video editing assistant");
+		expect(callArgs.tools).toHaveLength(1);
+		expect(callArgs.tools[0].functionDeclarations).toHaveLength(1);
+	});
+
+	test("passes multi-turn conversation through to Gemini", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({ text: "Sure!" }),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+		await adapter.chat({
+			messages: [
+				makeChatMessage("user", "First question"),
+				makeChatMessage("assistant", "First answer"),
+				makeChatMessage("user", "Second question"),
+			],
+			systemPrompt: "",
+			tools: [],
+		});
+
+		const callArgs = mockGenerateContent.mock.calls[0][0];
+		expect(callArgs.contents).toHaveLength(3);
+		expect(callArgs.contents[0].role).toBe("user");
+		expect(callArgs.contents[1].role).toBe("model");
+		expect(callArgs.contents[2].role).toBe("user");
+	});
+
+	test("does not include systemInstruction when systemPrompt is empty", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({ text: "OK" }),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+		await adapter.chat({
+			messages: [makeChatMessage("user", "Hi")],
+			systemPrompt: "",
+			tools: [],
+		});
+
+		const callArgs = mockGenerateContent.mock.calls[0][0];
+		expect(callArgs.systemInstruction).toBeUndefined();
+	});
+
+	test("ignores baseUrl in config — Gemini still works", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({ text: "Hello!" }),
+		);
+
+		const configWithBaseUrl: ProviderConfig = {
+			provider: "gemini",
+			apiKey: "test-gemini-key",
+			model: "gemini-2.0-flash",
+			baseUrl: "https://should-be-ignored.example.com",
+		};
+
+		const adapter = new GeminiAdapter(configWithBaseUrl);
+		const result = await adapter.chat({
+			messages: [makeChatMessage("user", "Hi")],
+			systemPrompt: "",
+			tools: [],
+		});
+
+		expect(result.content).toBe("Hello!");
+		expect(result.toolCalls).toBeUndefined();
+	});
+
+	test("returns text when tools are provided but Gemini responds with text only", async () => {
+		mockGenerateContent.mockResolvedValueOnce(
+			makeGeminiResponse({ text: "I don't need any tools for this." }),
+		);
+
+		const adapter = new GeminiAdapter(TEST_CONFIG);
+		const result = await adapter.chat({
+			messages: [makeChatMessage("user", "Just chat")],
+			systemPrompt: "You are helpful.",
+			tools: SAMPLE_TOOLS,
+		});
+
+		expect(result.content).toBe("I don't need any tools for this.");
+		expect(result.toolCalls).toBeUndefined();
+
+		// Verify tools were still sent to Gemini
+		const callArgs = mockGenerateContent.mock.calls[0][0];
+		expect(callArgs.tools).toBeDefined();
+		expect(callArgs.tools[0].functionDeclarations).toHaveLength(1);
+	});
+});
diff --git a/apps/web/src/agent/providers/__tests__/index.test.ts b/apps/web/src/agent/providers/__tests__/index.test.ts
index 913475a5..73478897 100644
--- a/apps/web/src/agent/providers/__tests__/index.test.ts
+++ b/apps/web/src/agent/providers/__tests__/index.test.ts
@@ -1,6 +1,7 @@
 import { describe, expect, test } from "bun:test";
 import { createProvider } from "@/agent/providers/index";
 import { OpenAICompatibleAdapter } from "@/agent/providers/openai-compatible";
+import { GeminiAdapter } from "@/agent/providers/gemini";
 import type { ProviderConfig } from "@/agent/providers/types";
 
 describe("createProvider", () => {
@@ -28,6 +29,17 @@ describe("createProvider", () => {
 		// Adapter was constructed without throwing — config accepted
 	});
 
+	test("returns GeminiAdapter for gemini provider", () => {
+		const config: ProviderConfig = {
+			provider: "gemini",
+			apiKey: "test-gemini-key",
+			model: "gemini-2.0-flash",
+		};
+
+		const adapter = createProvider(config);
+		expect(adapter).toBeInstanceOf(GeminiAdapter);
+	});
+
 	test("throws Error for unknown provider", () => {
 		const config: ProviderConfig = {
 			provider: "unknown-provider",
diff --git a/apps/web/src/agent/providers/gemini.ts b/apps/web/src/agent/providers/gemini.ts
new file mode 100644
index 00000000..33961e3e
--- /dev/null
+++ b/apps/web/src/agent/providers/gemini.ts
@@ -0,0 +1,240 @@
+import {
+	GoogleGenerativeAI,
+	type Content,
+	type FunctionDeclaration,
+	type FunctionDeclarationSchema,
+	type GenerateContentResult,
+	SchemaType,
+} from "@google/generative-ai";
+import type { ChatMessage, ToolCall, ToolSchema } from "@/agent/types";
+import type {
+	ProviderAdapter,
+	ProviderConfig,
+	ProviderResponse,
+} from "./types";
+
+// ---------------------------------------------------------------------------
+// Internal conversion helpers
+// ---------------------------------------------------------------------------
+
+/**
+ * Maps internal type strings to Gemini SchemaType values.
+ */
+const TYPE_MAP: Record<string, SchemaType> = {
+	string: SchemaType.STRING,
+	number: SchemaType.NUMBER,
+	boolean: SchemaType.BOOLEAN,
+	object: SchemaType.OBJECT,
+};
+
+/**
+ * Converts internal ChatMessages into Gemini Content[].
+ *
+ * - `user`       → role "user", text part
+ * - `assistant`  → role "model", text part + functionCall parts from toolCalls
+ * - `tool_result`→ role "function", functionResponse part
+ * - `system`     → skipped (handled separately via systemInstruction)
+ */
+export function toGeminiContents(messages: ChatMessage[]): Content[] {
+	const contents: Content[] = [];
+
+	for (const msg of messages) {
+		if (msg.role === "system") {
+			continue;
+		}
+
+		if (msg.role === "user") {
+			contents.push({
+				role: "user",
+				parts: [{ text: msg.content }],
+			});
+		} else if (msg.role === "assistant") {
+			const parts: Content["parts"] = [];
+
+			if (msg.content) {
+				parts.push({ text: msg.content });
+			}
+
+			if (msg.toolCalls && msg.toolCalls.length > 0) {
+				for (const tc of msg.toolCalls) {
+					parts.push({
+						functionCall: { name: tc.name, args: tc.args },
+					});
+				}
+			}
+
+			contents.push({ role: "model", parts });
+		} else if (msg.role === "tool_result") {
+			// Gemini uses the function name to correlate responses, not IDs.
+			// We parse the content as JSON for the response object; fall back
+			// to wrapping it if it's not valid JSON.
+			let responseData: object;
+			try {
+				responseData = JSON.parse(msg.content) as object;
+			} catch {
+				responseData = { result: msg.content };
+			}
+
+			// Derive the function name from the toolCallId → find the matching
+			// tool name in prior messages. If not found, use a placeholder.
+			const toolName = findToolNameForResult(messages, msg.toolCallId);
+
+			contents.push({
+				role: "function",
+				parts: [
+					{
+						functionResponse: {
+							name: toolName,
+							response: responseData,
+						},
+					},
+				],
+			});
+		}
+	}
+
+	return contents;
+}
+
+/**
+ * Walks backward through messages to find the function name associated with
+ * a toolCallId. This is needed because Gemini's functionResponse uses names,
+ * not IDs.
+ */
+function findToolNameForResult(
+	messages: ChatMessage[],
+	toolCallId?: string,
+): string {
+	if (!toolCallId) return "unknown";
+
+	for (let i = messages.length - 1; i >= 0; i--) {
+		const msg = messages[i];
+		if (msg.role === "assistant" && msg.toolCalls) {
+			const match = msg.toolCalls.find((tc) => tc.id === toolCallId);
+			if (match) return match.name;
+		}
+	}
+
+	return "unknown";
+}
+
+/**
+ * Converts internal ToolSchema[] into Gemini FunctionDeclaration[].
+ *
+ * Maps internal type strings ("string", "number", etc.) to Gemini SchemaType
+ * enum values. Returns an empty array when no tools are provided.
+ */
+export function toGeminiTools(tools: ToolSchema[]): FunctionDeclaration[] {
+	if (tools.length === 0) return [];
+
+	return tools.map((tool) => {
+		const properties: FunctionDeclarationSchema["properties"] = {};
+
+		for (const param of tool.parameters) {
+			const geminiType = TYPE_MAP[param.type] ?? SchemaType.STRING;
+			// eslint-disable-next-line @typescript-eslint/no-explicit-any
+			(properties as Record<string, any>)[param.key] = { type: geminiType };
+		}
+
+		const requiredParams = tool.parameters
+			.filter((p) => p.required)
+			.map((p) => p.key);
+
+		return {
+			name: tool.name,
+			description: tool.description,
+			parameters: {
+				type: SchemaType.OBJECT,
+				properties,
+				...(requiredParams.length > 0 && { required: requiredParams }),
+			},
+		};
+	});
+}
+
+/**
+ * Converts a Gemini GenerateContentResult into the provider-agnostic
+ * ProviderResponse shape.
+ *
+ * - Text parts are concatenated into `content`.
+ * - FunctionCall parts are mapped to `toolCalls[]` with synthesized UUIDs.
+ * - Throws if no candidates are present.
+ */
+export function fromGeminiResponse(
+	response: GenerateContentResult,
+): ProviderResponse {
+	const candidates = response.response.candidates;
+	if (!candidates || candidates.length === 0) {
+		throw new Error("Empty response from Gemini provider");
+	}
+
+	const parts = candidates[0].content?.parts ?? [];
+	const textParts: string[] = [];
+	const toolCalls: ToolCall[] = [];
+
+	for (const part of parts) {
+		if ("text" in part && part.text !== undefined) {
+			textParts.push(part.text);
+		}
+		if ("functionCall" in part && part.functionCall) {
+			toolCalls.push({
+				id: crypto.randomUUID(),
+				name: part.functionCall.name,
+				args: (part.functionCall.args as Record<string, unknown>) ?? {},
+			});
+		}
+	}
+
+	const content = textParts.join("");
+	const result: ProviderResponse = { content };
+
+	if (toolCalls.length > 0) {
+		result.toolCalls = toolCalls;
+	}
+
+	return result;
+}
+
+// ---------------------------------------------------------------------------
+// Adapter implementation
+// ---------------------------------------------------------------------------
+
+/**
+ * Gemini adapter using @google/generative-ai SDK.
+ *
+ * Uses the stateless `generateContent()` API — full history is sent with each
+ * call, matching the existing route contract. System prompts are mapped to
+ * Gemini's `systemInstruction` field, not as user messages.
+ */
+export class GeminiAdapter implements ProviderAdapter {
+	private model;
+
+	constructor(config: ProviderConfig) {
+		const genAI = new GoogleGenerativeAI(config.apiKey);
+		this.model = genAI.getGenerativeModel({ model: config.model });
+		// config.baseUrl is intentionally ignored for the Gemini provider.
+	}
+
+	async chat(params: {
+		messages: ChatMessage[];
+		systemPrompt: string;
+		tools: ToolSchema[];
+	}): Promise<ProviderResponse> {
+		const contents = toGeminiContents(params.messages);
+		const functionDeclarations = toGeminiTools(params.tools);
+
+		// eslint-disable-next-line @typescript-eslint/no-explicit-any
+		const request: any = { contents };
+
+		if (params.systemPrompt) {
+			request.systemInstruction = params.systemPrompt;
+		}
+
+		if (functionDeclarations.length > 0) {
+			request.tools = [{ functionDeclarations }];
+		}
+
+		const result = await this.model.generateContent(request);
+		return fromGeminiResponse(result);
+	}
+}
diff --git a/apps/web/src/agent/providers/index.ts b/apps/web/src/agent/providers/index.ts
index 5bbb2cdb..8939f6ad 100644
--- a/apps/web/src/agent/providers/index.ts
+++ b/apps/web/src/agent/providers/index.ts
@@ -1,5 +1,6 @@
 import type { ProviderAdapter, ProviderConfig } from "./types";
 import { OpenAICompatibleAdapter } from "./openai-compatible";
+import { GeminiAdapter } from "./gemini";
 
 /**
  * Factory — resolves a ProviderConfig to a concrete adapter.
@@ -12,6 +13,8 @@ export function createProvider(config: ProviderConfig): ProviderAdapter {
 	switch (config.provider) {
 		case "openai-compatible":
 			return new OpenAICompatibleAdapter(config);
+		case "gemini":
+			return new GeminiAdapter(config);
 		default:
 			throw new Error(`Unknown LLM provider: ${config.provider}`);
 	}
diff --git a/apps/web/src/agent/system-prompt.ts b/apps/web/src/agent/system-prompt.ts
index 26b4229c..37407700 100644
--- a/apps/web/src/agent/system-prompt.ts
+++ b/apps/web/src/agent/system-prompt.ts
@@ -17,7 +17,7 @@ export function buildSystemPrompt(
 ): string {
 	const mediaSection =
 		context.mediaAssets.length > 0
-			? `Active media assets:\n${context.mediaAssets.map((m) => `- ${m.name} (${m.type}, ${m.duration}s)`).join("\n")}`
+			? `Active media assets:\n${context.mediaAssets.map((m) => `- [id: ${m.id}] ${m.name} (${m.type}, ${m.duration}s)`).join("\n")}`
 			: "No media assets loaded.";
 
 	const parts = [
@@ -28,6 +28,12 @@ export function buildSystemPrompt(
 		mediaSection,
 	];
 
+	if (context.mediaAssets.length > 0) {
+		parts.push(
+			'IMPORTANT: When calling tools that accept an "assetId" parameter, always use the internal "id" value (e.g., "v1"), NOT the filename or display name.',
+		);
+	}
+
 	if (tools && tools.length > 0) {
 		const toolList = tools
 			.map((t) => `- ${t.name}: ${t.description}`)
diff --git a/apps/web/src/agent/tools/__tests__/transcribe-video.test.ts b/apps/web/src/agent/tools/__tests__/transcribe-video.test.ts
index af52caea..9b1c474d 100644
--- a/apps/web/src/agent/tools/__tests__/transcribe-video.test.ts
+++ b/apps/web/src/agent/tools/__tests__/transcribe-video.test.ts
@@ -227,7 +227,7 @@ describe("transcribe_video tool — error branches", () => {
 
 		const result = await tool.execute({ assetId: "v99" }, context);
 		expect(result).toEqual({
-			error: "Could not access file for asset v99",
+			error: 'No asset found with id or name "v99". Available ids: [v1]. Available names: [intro.mp4].',
 		});
 	});
 
@@ -282,3 +282,141 @@ describe("transcribe_video tool — error branches", () => {
 		expect(result).toEqual({ error: "Worker not initialized" });
 	});
 });
+
+describe("transcribe_video tool — name-based assetId fallback", () => {
+	beforeEach(() => {
+		mockResolveAssetFile.mockClear();
+		mockGetAssetHasAudio.mockClear();
+		mockDecodeAudio.mockClear();
+		mockTranscribe.mockClear();
+	});
+
+	test("resolves by filename when no id match (exact name)", async () => {
+		const fakeFile = new File([], "conclu.mov", { type: "video/quicktime" });
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "abc123", name: "conclu.mov" }),
+			],
+		});
+
+		mockResolveAssetFile.mockReturnValue(fakeFile);
+		mockGetAssetHasAudio.mockReturnValue(true);
+		mockDecodeAudio.mockResolvedValue({
+			samples: new Float32Array(16000),
+			sampleRate: 16000,
+		});
+		mockTranscribe.mockResolvedValue(fakeTranscriptionResult());
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "conclu.mov" }, context);
+
+		expect(result).toEqual(
+			expect.objectContaining({ assetName: "conclu.mov" }),
+		);
+		// Resolved asset must pass its internal id to the adapter
+		expect(mockResolveAssetFile).toHaveBeenCalledWith("abc123");
+		expect(mockGetAssetHasAudio).toHaveBeenCalledWith("abc123");
+	});
+
+	test("resolves by case-insensitive name when no exact id or name match", async () => {
+		const fakeFile = new File([], "Conclu.MOV", { type: "video/quicktime" });
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "abc123", name: "Conclu.MOV" }),
+			],
+		});
+
+		mockResolveAssetFile.mockReturnValue(fakeFile);
+		mockGetAssetHasAudio.mockReturnValue(true);
+		mockDecodeAudio.mockResolvedValue({
+			samples: new Float32Array(16000),
+			sampleRate: 16000,
+		});
+		mockTranscribe.mockResolvedValue(fakeTranscriptionResult());
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "conclu.mov" }, context);
+
+		expect(result).toEqual(
+			expect.objectContaining({ assetName: "Conclu.MOV" }),
+		);
+		expect(mockResolveAssetFile).toHaveBeenCalledWith("abc123");
+	});
+
+	test("returns ambiguous error when two assets share same name", async () => {
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "v1", name: "clip.mp4" }),
+				fakeVideoAsset({ id: "v2", name: "clip.mp4" }),
+			],
+		});
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "clip.mp4" }, context);
+
+		expect(result).toEqual({
+			error: 'Ambiguous asset name "clip.mp4" matches multiple assets (clip.mp4, clip.mp4). Specify the internal id: v1, v2.',
+		});
+	});
+
+	test("returns ambiguous error for case-insensitive duplicates", async () => {
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "v1", name: "Clip.MP4" }),
+				fakeVideoAsset({ id: "v2", name: "CLIP.MP4" }),
+			],
+		});
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "clip.mp4" }, context);
+
+		expect(result).toEqual({
+			error: 'Ambiguous asset name "clip.mp4" matches multiple assets (Clip.MP4, CLIP.MP4). Specify the internal id: v1, v2.',
+		});
+	});
+
+	test("prefers exact id match over name match", async () => {
+		const fakeFile = new File([], "intro.mp4", { type: "video/mp4" });
+		// An asset whose id happens to equal another asset's name
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "v1", name: "intro.mp4" }),
+				fakeVideoAsset({ id: "intro.mp4", name: "outro.mp4" }),
+			],
+		});
+
+		mockResolveAssetFile.mockReturnValue(fakeFile);
+		mockGetAssetHasAudio.mockReturnValue(true);
+		mockDecodeAudio.mockResolvedValue({
+			samples: new Float32Array(16000),
+			sampleRate: 16000,
+		});
+		mockTranscribe.mockResolvedValue(fakeTranscriptionResult());
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "intro.mp4" }, context);
+
+		// "intro.mp4" matches v1 by id AND the second asset by id exactly
+		// id lookup is first, so it resolves the second asset (id="intro.mp4")
+		expect(result).toEqual(
+			expect.objectContaining({ assetName: "outro.mp4" }),
+		);
+		expect(mockResolveAssetFile).toHaveBeenCalledWith("intro.mp4");
+	});
+
+	test("returns not-found error with available ids and names for totally unknown assetId", async () => {
+		const context = makeContext({
+			mediaAssets: [
+				fakeVideoAsset({ id: "v1", name: "intro.mp4" }),
+				fakeVideoAsset({ id: "v2", name: "outro.mp4" }),
+			],
+		});
+
+		const tool = toolRegistry.get("transcribe_video");
+		const result = await tool.execute({ assetId: "nonexistent.mov" }, context);
+
+		expect(result).toEqual({
+			error: 'No asset found with id or name "nonexistent.mov". Available ids: [v1, v2]. Available names: [intro.mp4, outro.mp4].',
+		});
+	});
+});
diff --git a/apps/web/src/agent/tools/transcribe-video.tool.ts b/apps/web/src/agent/tools/transcribe-video.tool.ts
index 805cd8f0..e121e7ae 100644
--- a/apps/web/src/agent/tools/transcribe-video.tool.ts
+++ b/apps/web/src/agent/tools/transcribe-video.tool.ts
@@ -57,10 +57,43 @@ const transcribeVideoTool: ToolDefinition = {
 		let targetAsset: (typeof mediaCandidates)[number] | undefined;
 
 		if (typedArgs.assetId) {
+			// 1. Exact internal-id match
 			targetAsset = mediaCandidates.find((a) => a.id === typedArgs.assetId);
+
+			// 2. Fallback: exact name match (LLM sometimes passes filename)
 			if (!targetAsset) {
+				const nameMatches = mediaCandidates.filter(
+					(a) => a.name === typedArgs.assetId,
+				);
+				if (nameMatches.length === 1) {
+					targetAsset = nameMatches[0];
+				} else if (nameMatches.length > 1) {
+					return {
+						error: `Ambiguous asset name "${typedArgs.assetId}" matches multiple assets (${nameMatches.map((a) => a.name).join(", ")}). Specify the internal id: ${nameMatches.map((a) => `${a.id}`).join(", ")}.`,
+					};
+				}
+			}
+
+			// 3. Case-insensitive fallback (only if unambiguous)
+			if (!targetAsset) {
+				const lower = typedArgs.assetId.toLowerCase();
+				const ciMatches = mediaCandidates.filter(
+					(a) => a.name.toLowerCase() === lower,
+				);
+				if (ciMatches.length === 1) {
+					targetAsset = ciMatches[0];
+				} else if (ciMatches.length > 1) {
+					return {
+						error: `Ambiguous asset name "${typedArgs.assetId}" matches multiple assets (${ciMatches.map((a) => a.name).join(", ")}). Specify the internal id: ${ciMatches.map((a) => `${a.id}`).join(", ")}.`,
+					};
+				}
+			}
+
+			if (!targetAsset) {
+				const ids = mediaCandidates.map((a) => a.id).join(", ");
+				const names = mediaCandidates.map((a) => a.name).join(", ");
 				return {
-					error: `Could not access file for asset ${typedArgs.assetId}`,
+					error: `No asset found with id or name "${typedArgs.assetId}". Available ids: [${ids}]. Available names: [${names}].`,
 				};
 			}
 		} else {
diff --git a/bun.lock b/bun.lock
index a39f2c2f..f1dd7d86 100644
--- a/bun.lock
+++ b/bun.lock
@@ -20,6 +20,7 @@
       "name": "@opencut/web",
       "version": "0.1.0",
       "dependencies": {
+        "@google/generative-ai": "^0.24.0",
         "@hello-pangea/dnd": "^18.0.1",
         "@hugeicons/core-free-icons": "^3.3.0",
         "@hugeicons/react": "^1.1.6",
@@ -348,6 +349,8 @@
 
     "@floating-ui/utils": ["@floating-ui/utils@0.2.10", "", {}, "sha512-aGTxbpbg8/b5JfU1HXSrbH3wXZuLPJcNEcZQFMxLs3oSzgtVu6nFPkbbGGUvBcUjKV2YyB9Wxxabo+HEH9tcRQ=="],
 
+    "@google/generative-ai": ["@google/generative-ai@0.24.1", "", {}, "sha512-MqO+MLfM6kjxcKoy0p1wRzG3b4ZZXtPI+z2IE26UogS2Cm/XHO+7gGRBh6gcJsOiIVoH93UwKvW4HdgiOZCy9Q=="],
+
     "@hello-pangea/dnd": ["@hello-pangea/dnd@18.0.1", "", { "dependencies": { "@babel/runtime": "^7.26.7", "css-box-model": "^1.2.1", "raf-schd": "^4.0.3", "react-redux": "^9.2.0", "redux": "^5.0.1" }, "peerDependencies": { "react": "^18.0.0 || ^19.0.0", "react-dom": "^18.0.0 || ^19.0.0" } }, "sha512-xojVWG8s/TGrKT1fC8K2tIWeejJYTAeJuj36zM//yEm/ZrnZUSFGS15BpO+jGZT1ybWvyXmeDJwPYb4dhWlbZQ=="],
 
     "@hugeicons/core-free-icons": ["@hugeicons/core-free-icons@3.3.0", "", {}, "sha512-qYyr4JQ2eQIHTSTbITvnJvs6ERNK64D9gpwZnf2IyuG0exzqfyABLO/oTB71FB3RZPfu1GbwycdiGSo46apjMQ=="],
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/archive-report.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/archive-report.md
new file mode 100644
index 00000000..3046c859
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/archive-report.md
@@ -0,0 +1,59 @@
+# Archive Report: gemini-adapter-fase-1
+
+**Change**: gemini-adapter-fase-1
+**Archived**: 2026-04-24
+**Verification Verdict**: PASS — 14/14 tasks complete, 12/12 spec scenarios compliant, 48/48 tests passing, 0 TypeScript errors
+
+## Scope Summary
+
+This change adds **native Gemini provider support for normal chat and tool calling only**. Video upload/file understanding remains deferred to a future change. The `GeminiAdapter` implements the existing `ProviderAdapter` seam via `@google/generative-ai` SDK, supporting stateless `generateContent()` with system prompt mapping, tool schema conversion, and synthesized tool-call IDs. The OpenAI-compatible path is untouched.
+
+## Engram Artifact Traceability
+
+| Artifact | Observation ID |
+|----------|---------------|
+| Proposal | #1016 |
+| Spec (delta) | #1019 |
+| Design | #1018 |
+| Tasks | #1020 |
+| Apply Progress | #1021 |
+| Verify Report | #1024 |
+
+## OpenSpec Archive
+
+**Moved to**: `openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/`
+
+### Archive Contents
+- proposal.md ✅
+- specs/ (agent-session-shell delta) ✅
+- design.md ✅
+- tasks.md ✅ (14/14 tasks complete)
+- verify-report.md ✅
+- exploration.md ✅
+
+## Specs Synced
+
+| Domain | Action | Details |
+|--------|--------|---------|
+| agent-session-shell | Updated | 2 requirements modified (Provider Adapter Interface, Provider Configuration), 2 requirements added (Gemini Free-Form Chat, Gemini Tool Calling), 0 removed |
+
+### Modified Requirements
+- **Provider Adapter Interface**: Expanded factory to support `openai-compatible` and `gemini`; added tool-call ID synthesis mandate; added Gemini adapter selection scenario
+- **Provider Configuration**: Added `LLM_PROVIDER` valid value constraint (`openai-compatible`, `gemini`); added Gemini-specific `LLM_BASE_URL` ignoring behavior; added unknown-provider and Gemini-config scenarios
+
+### Added Requirements
+- **Gemini Free-Form Chat**: Plain text chat through Gemini `generateContent()` with system prompt mapped to `systemInstruction`
+- **Gemini Tool Calling**: Tool schema → Gemini function declaration conversion, function call response → `ToolCall[]` with synthesized IDs
+
+## Source of Truth Updated
+- `openspec/specs/agent-session-shell/spec.md` — now reflects Gemini provider support
+
+## Deferred Scope (explicitly out of scope)
+- Video/file upload or direct file understanding
+- `@asset` references, broader multimodal inputs, image/video reasoning
+- Streaming UX or adapter contract changes for streaming
+- Safety/grounding/thinking configuration beyond defaults
+
+## SDD Cycle Complete
+The change has been fully explored, proposed, specified, designed, implemented, verified, and archived.
+Ready for the next change.
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/design.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/design.md
new file mode 100644
index 00000000..282e6c5d
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/design.md
@@ -0,0 +1,155 @@
+# Design: Gemini Adapter — Phase 1
+
+## Technical Approach
+
+Implement a stateless `GeminiAdapter` class behind the existing `ProviderAdapter` seam, following the exact same pattern as `OpenAICompatibleAdapter`. The adapter converts internal `ChatMessage[]`/`ToolSchema[]` into Gemini's `generateContent()` wire format and parses responses back into `ProviderResponse`. A new `"gemini"` case in `createProvider()` activates it when `LLM_PROVIDER=gemini`. Zero changes to orchestrator, route, or client contracts.
+
+## Architecture Decisions
+
+### Decision: SDK choice
+
+| Option | Tradeoff | Decision |
+|--------|----------|----------|
+| `@google/generative-ai` | Established, stable, v0.21+, `GoogleGenerativeAI` class, `generateContent()` stateless API | ✅ Selected |
+| `@google/genai` | Newer unified SDK, less battle-tested, API may still shift | ❌ Rejected |
+
+**Rationale**: `@google/generative-ai` is the most widely adopted Gemini SDK for Node/TS. It supports `systemInstruction`, `functionDeclaration`, and stateless `generateContent()` — exactly what we need. Consistent with using the mature `openai` SDK for the existing adapter.
+
+### Decision: Stateless generateContent vs stateful startChat
+
+| Option | Tradeoff | Decision |
+|--------|----------|----------|
+| `model.generateContent(contents, config)` | Stateless, full history each call — matches current adapter contract | ✅ Selected |
+| `chat.sendMessage()` via `startChat()` | Stateful session, server-managed history | ❌ Rejected |
+
+**Rationale**: Current architecture POSTs full history from client on every turn. Stateless `generateContent()` maps 1:1 to this pattern. No session management needed.
+
+### Decision: Tool call ID synthesis
+
+| Option | Tradeoff | Decision |
+|--------|----------|----------|
+| `crypto.randomUUID()` | Built-in, zero deps, unique | ✅ Selected |
+| `nanoid()` (already a dep) | Shorter IDs, also unique | ❌ Rejected |
+
+**Rationale**: `crypto.randomUUID()` is universally available in Node/Bun, no import needed, and produces standard UUIDs matching OpenAI's `call_xxx` format semantically. Keeps the adapter self-contained.
+
+### Decision: System prompt placement
+
+| Option | Tradeoff | Decision |
+|--------|----------|----------|
+| `systemInstruction` on `GenerateContentRequest` | Gemini-native, separate from contents | ✅ Selected |
+| Prepend as `user` message | Works but dilutes system/user boundary | ❌ Rejected |
+
+**Rationale**: Gemini SDK supports `systemInstruction` as a first-class config field. Using it keeps system prompt semantically correct and matches Gemini best practices.
+
+## Data Flow
+
+```
+Route (chat/route.ts)
+  │
+  ├─ createProvider(config)  →  GeminiAdapter instance
+  │
+  └─ adapter.chat({ messages, systemPrompt, tools })
+       │
+       ├─ toGeminiContents(messages)     →  Content[] (user/model/function)
+       ├─ toGeminiTools(tools)           →  FunctionDeclaration[]
+       │
+       └─ model.generateContent({ contents, tools, systemInstruction })
+            │
+            └─ fromGeminiResponse(response)  →  ProviderResponse
+                  │
+                  ├─ content: candidate.content.parts[].text
+                  └─ toolCalls: candidate.content.parts[]
+                       .filter(functionCall)
+                       .map → { id: uuid(), name, args }
+```
+
+### Message mapping
+
+| Internal role | Gemini role | Notes |
+|---------------|-------------|-------|
+| `system` | `systemInstruction` (config) | Not in contents array |
+| `user` | `user` part | Direct text mapping |
+| `assistant` | `model` part | Includes `functionCall` parts for tool calls |
+| `tool_result` | `function` role | Uses `functionResponse: { name, response }` keyed by tool name (not ID) |
+
+### Type mapping (internal → Gemini)
+
+| Internal type | Gemini type |
+|---------------|-------------|
+| `"string"` | `SchemaType.STRING` |
+| `"number"` | `SchemaType.NUMBER` |
+| `"boolean"` | `SchemaType.BOOLEAN` |
+| `"object"` | `SchemaType.OBJECT` |
+
+## File Changes
+
+| File | Action | Description |
+|------|--------|-------------|
+| `apps/web/src/agent/providers/gemini.ts` | Create | GeminiAdapter + conversion helpers (`toGeminiContents`, `toGeminiTools`, `fromGeminiResponse`) |
+| `apps/web/src/agent/providers/index.ts` | Modify | Add `"gemini"` case to factory switch |
+| `apps/web/src/agent/providers/__tests__/gemini.test.ts` | Create | Conversion tests, error paths, tool call ID synthesis |
+| `apps/web/src/agent/providers/__tests__/index.test.ts` | Modify | Add factory test for `"gemini"` → `GeminiAdapter` |
+| `apps/web/package.json` | Modify | Add `@google/generative-ai` dependency |
+| `apps/web/.env.example` | Modify | Add Gemini example config lines |
+
+## Interfaces / Contracts
+
+No interface changes. The adapter implements the existing `ProviderAdapter`:
+
+```ts
+// Reused as-is from providers/types.ts
+interface ProviderAdapter {
+  chat(params: {
+    messages: ChatMessage[];
+    systemPrompt: string;
+    tools: ToolSchema[];
+  }): Promise<ProviderResponse>;
+}
+```
+
+### Internal helper signatures (gemini.ts)
+
+```ts
+function toGeminiContents(
+  messages: ChatMessage[],
+): GenerateContentRequest["contents"];
+
+function toGeminiTools(
+  tools: ToolSchema[],
+): FunctionDeclaration[];
+
+function fromGeminiResponse(
+  response: GenerateContentResult,
+): ProviderResponse;
+```
+
+### Tool call ID — name collision handling
+
+When mapping `tool_result` back to Gemini's `functionResponse`, Gemini keys by function **name** not ID. If multiple calls to the same tool exist in history, we group them by name and send the last result per name. This is acceptable because:
+
+1. Current tool set (`transcribe_video`) is single-invocation per turn
+2. Multi-call same-tool scenarios are deferred to a later change
+3. Orchestrator already handles the ID→name correlation client-side
+
+## Testing Strategy
+
+| Layer | What to Test | Approach |
+|-------|-------------|----------|
+| Unit | `toGeminiContents` mapping (user, assistant, tool_result, assistant+toolCalls) | Mock SDK, inspect call args |
+| Unit | `toGeminiTools` type casing (string→STRING, etc.) | Direct assertion on output |
+| Unit | `fromGeminiResponse` content extraction | Construct Gemini response shape, assert `ProviderResponse` |
+| Unit | Tool call ID synthesis (non-empty, unique) | Multiple calls produce different IDs |
+| Unit | Error: empty candidates → throws | Assert error message |
+| Unit | Error: SDK throws → propagates | Assert error bubbles up |
+| Unit | Factory: `"gemini"` → `GeminiAdapter` | Instance check |
+| Integration | Full `chat()` round-trip with mocked SDK | End-to-end within adapter |
+
+## Migration / Rollout
+
+No migration required. Additive change — setting `LLM_PROVIDER=gemini` activates the new adapter. Existing `openai-compatible` default is untouched.
+
+## Open Questions
+
+- [ ] Confirm `@google/generative-ai` latest stable version at impl time (currently ^0.21)
+- [ ] Verify Gemini model naming convention user will use (e.g. `gemini-2.0-flash` vs `models/gemini-2.0-flash`)
diff --git a/openspec/changes/gemini-adapter-fase-1/exploration.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/exploration.md
similarity index 100%
rename from openspec/changes/gemini-adapter-fase-1/exploration.md
rename to openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/exploration.md
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/proposal.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/proposal.md
new file mode 100644
index 00000000..6719a596
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/proposal.md
@@ -0,0 +1,65 @@
+# Proposal: Gemini Adapter — Phase 1
+
+## Intent
+
+Add Gemini as a native provider behind the existing provider-agnostic LLM seam so the agent can use Gemini for plain chat and tool calling without changing orchestrator or route contracts.
+
+## Scope
+
+### In Scope
+- Native `GeminiAdapter` implementing the current `ProviderAdapter`
+- Gemini free-form chat using existing stateless full-history flow
+- Gemini tool calling, with `transcribe_video` as the first real tool
+- Config support for `LLM_PROVIDER=gemini`, `LLM_API_KEY`, `LLM_MODEL`
+- Tests and env/docs updates while preserving the OpenAI-compatible path
+
+### Out of Scope
+- Video/file upload or direct file understanding
+- `@asset` references, broader multimodal inputs, and image/video reasoning
+- Streaming UX or adapter contract changes for streaming
+- Safety/grounding/thinking configuration beyond defaults
+
+## Capabilities
+
+### New Capabilities
+- None
+
+### Modified Capabilities
+- `agent-session-shell`: expand provider selection/configuration so the existing provider adapter contract also supports native Gemini chat and function calling
+
+## Approach
+
+Implement a native Gemini SDK-backed adapter and register it in the provider factory. Keep the adapter stateless by mapping full internal message history into Gemini `generateContent()` requests, converting tool schemas/results at the adapter boundary, and synthesizing tool call IDs so internal contracts stay unchanged.
+
+## Affected Areas
+
+| Area | Impact | Description |
+|------|--------|-------------|
+| `apps/web/src/agent/providers/gemini.ts` | New | Gemini request/response/tool conversion |
+| `apps/web/src/agent/providers/index.ts` | Modified | Factory registration for `gemini` |
+| `apps/web/src/agent/providers/__tests__/gemini.test.ts` | New | Adapter conversion/error tests |
+| `apps/web/src/agent/providers/__tests__/index.test.ts` | Modified | Factory coverage |
+| `apps/web/package.json` | Modified | Gemini SDK dependency |
+| `apps/web/.env.example` | Modified | Gemini env configuration |
+
+## Risks
+
+| Risk | Likelihood | Mitigation |
+|------|------------|------------|
+| Gemini has no tool call IDs | Med | Synthesize unique IDs inside adapter |
+| Gemini type casing differs from internal schema | Med | Centralize schema mapping tests |
+| Gemini system prompt placement differs | Low | Map system prompt explicitly to Gemini config |
+
+## Rollback Plan
+
+Remove the Gemini adapter, factory branch, dependency, and env docs; keep `openai-compatible` as the unchanged default path.
+
+## Dependencies
+
+- Gemini JS SDK selection to be verified during implementation
+
+## Success Criteria
+
+- [ ] `LLM_PROVIDER=gemini` resolves a native Gemini adapter without breaking `openai-compatible`
+- [ ] Gemini returns normal assistant text through the existing route/orchestrator flow
+- [ ] Gemini can emit structured tool calls and execute `transcribe_video` through the existing loop
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/specs/agent-session-shell/spec.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/specs/agent-session-shell/spec.md
new file mode 100644
index 00000000..ea9fbc2e
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/specs/agent-session-shell/spec.md
@@ -0,0 +1,97 @@
+# Delta for agent-session-shell
+
+## MODIFIED Requirements
+
+### Requirement: Provider Adapter Interface
+
+The system SHALL define a server-side provider adapter interface with a single method `chat(params: ProviderChatParams): Promise<ProviderChatResponse>`. `ProviderChatParams` MUST include `messages`, `systemPrompt`, and `toolSchemas` in a provider-agnostic internal format. `ProviderChatResponse` MUST include `content: string` and `toolCalls?: ProviderToolCall[]` where `ProviderToolCall { id, name, args }`. Each concrete adapter converts internal tool schemas to its own wire format. The factory MUST support at least `openai-compatible` and `gemini` providers. Adapters whose native API does not assign IDs to tool calls MUST synthesize unique IDs so every returned `ToolCall.id` is a non-empty string.
+
+(Previously: Phase 1 MAY ship exactly one adapter (OpenAI-compatible) as long as the interface contract remains provider-agnostic.)
+
+#### Scenario: Adapter translates tool schemas to wire format
+
+- GIVEN `transcribe_video` has internal parameters `[{ key: "assetId", type: "string", required: false }]`
+- WHEN the adapter receives tool schemas before calling the provider
+- THEN it converts them to its provider-specific wire format
+
+#### Scenario: Adapter selected by config — OpenAI-compatible
+
+- GIVEN `LLM_PROVIDER` is set to `"openai-compatible"`
+- WHEN the route resolves the adapter
+- THEN the OpenAI-compatible adapter is returned
+
+#### Scenario: Adapter selected by config — Gemini
+
+- GIVEN `LLM_PROVIDER` is set to `"gemini"`
+- WHEN the route resolves the adapter
+- THEN the Gemini adapter is returned
+
+#### Scenario: Gemini adapter synthesizes tool-call IDs
+
+- GIVEN the Gemini API returns a function call response with no call ID
+- WHEN the Gemini adapter maps the response to `ProviderResponse`
+- THEN each `ToolCall` in `toolCalls` has a non-empty `id` field generated by the adapter
+
+### Requirement: Provider Configuration
+
+Server-only environment variables `LLM_PROVIDER` (required), `LLM_MODEL` (required), `LLM_API_KEY` (required), and `LLM_BASE_URL` (optional) MUST determine which adapter and model the route uses. `LLM_PROVIDER` MUST accept at least `"openai-compatible"` and `"gemini"`. When `LLM_PROVIDER` is `"gemini"`, `LLM_BASE_URL` MUST be ignored. Configuration MUST be read server-side only — never exposed to the client.
+
+(Previously: Provider config listed env vars but did not constrain valid provider values or describe Gemini-specific behavior.)
+
+#### Scenario: Missing required configuration
+
+- GIVEN `LLM_API_KEY` is not set in the environment
+- WHEN the route attempts to initialize the provider
+- THEN the call returns 502 with a missing-configuration error
+
+#### Scenario: Unknown provider
+
+- GIVEN `LLM_PROVIDER` is set to `"unknown-provider"`
+- WHEN the route resolves the adapter
+- THEN the factory throws `"Unknown LLM provider: unknown-provider"`
+
+#### Scenario: Gemini config ignores base URL
+
+- GIVEN `LLM_PROVIDER` is `"gemini"` and `LLM_BASE_URL` is set
+- WHEN the Gemini adapter is created
+- THEN `LLM_BASE_URL` is not used in the API call
+
+## ADDED Requirements
+
+### Requirement: Gemini Free-Form Chat
+
+When the Gemini adapter receives a request with no tool schemas (or tools array is empty), it MUST send messages to the Gemini `generateContent` API and return a `ProviderResponse` with `content` set to the assistant text and `toolCalls` undefined.
+
+#### Scenario: Plain chat through Gemini
+
+- GIVEN `LLM_PROVIDER` is `"gemini"` and messages contain `[{ role: "user", content: "Hello" }]`
+- WHEN the adapter calls Gemini and receives a text-only response
+- THEN `ProviderResponse.content` is the assistant text and `toolCalls` is undefined
+
+#### Scenario: System prompt mapping
+
+- GIVEN the adapter receives `systemPrompt: "You are a video editor"`
+- WHEN it builds the Gemini request
+- THEN the system prompt is mapped to Gemini's system instruction field, not as a user message
+
+### Requirement: Gemini Tool Calling
+
+When the Gemini adapter receives a request with tool schemas, it MUST convert internal `ToolSchema[]` to Gemini function declarations, call `generateContent` with declarations attached, and if Gemini returns function call parts, map each to a `ToolCall { id, name, args }` with a synthesized non-empty `id`.
+
+#### Scenario: Gemini returns function calls
+
+- GIVEN `transcribe_video` is in tool schemas and Gemini responds with a function call part `{ name: "transcribe_video", args: {} }`
+- WHEN the adapter maps the response
+- THEN `toolCalls` contains one `ToolCall` with `name: "transcribe_video"`, `args: {}`, and a synthesized `id`
+
+#### Scenario: Gemini returns text despite tools
+
+- GIVEN tool schemas are provided but Gemini responds with only text
+- WHEN the adapter maps the response
+- THEN `toolCalls` is undefined and `content` holds the text
+
+#### Scenario: Tool schema type mapping
+
+- GIVEN an internal tool schema has parameters `[{ key: "assetId", type: "string", required: true }]`
+- WHEN the adapter converts to Gemini function declarations
+- THEN the parameter appears in `FunctionDeclaration.parameters.properties` with type `"string"`
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/tasks.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/tasks.md
new file mode 100644
index 00000000..499ab63e
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/tasks.md
@@ -0,0 +1,28 @@
+# Tasks: Gemini Adapter — Phase 1
+
+## Phase 1: Foundation
+
+- [x] 1.1 Add `@google/generative-ai` dependency to `apps/web/package.json` (pin to latest stable `^0.21` or newer)
+- [x] 1.2 Add Gemini env config lines to `apps/web/.env.example`: `LLM_PROVIDER=gemini`, `LLM_API_KEY`, `LLM_MODEL=gemini-2.0-flash`, comment noting `LLM_BASE_URL` is ignored for gemini
+
+## Phase 2: Core Adapter
+
+- [x] 2.1 Create `apps/web/src/agent/providers/gemini.ts` — import `GoogleGenerativeAI` from `@google/generative-ai`, `SchemaType` for type mapping
+- [x] 2.2 Implement `toGeminiContents(messages: ChatMessage[])` — map `user→user`, `assistant→model` (with `functionCall` parts), `tool_result→function` role with `functionResponse`; skip `system` role (handled separately)
+- [x] 2.3 Implement `toGeminiTools(tools: ToolSchema[])` — convert each `ToolSchema` to a `FunctionDeclaration` with `SchemaType` property types (`string→STRING`, `number→NUMBER`, `boolean→BOOLEAN`, `object→OBJECT`); return empty array when no tools
+- [x] 2.4 Implement `fromGeminiResponse(response)` — extract `candidate.content.parts`, pull text into `content`, filter `functionCall` parts into `toolCalls[]` with `id: crypto.randomUUID()`, `name`, `args`; throw on empty candidates
+- [x] 2.5 Implement `GeminiAdapter` class — constructor takes `ProviderConfig`, creates `GoogleGenerativeAI` + `getGenerativeModel({ model, systemInstruction })`; `chat()` calls `model.generateContent({ contents, tools })` then returns `fromGeminiResponse()`; ignore `config.baseUrl`
+
+## Phase 3: Factory Integration
+
+- [x] 3.1 Add `"gemini"` case to `createProvider()` switch in `apps/web/src/agent/providers/index.ts` — import and return `new GeminiAdapter(config)`
+- [x] 3.2 Verify existing `openai-compatible` factory case is untouched and all existing tests still pass
+
+## Phase 4: Tests
+
+- [x] 4.1 Create `apps/web/src/agent/providers/__tests__/gemini.test.ts` — test `toGeminiContents`: user message, assistant with toolCalls, tool_result mapping, system message excluded from contents
+- [x] 4.2 Test `toGeminiTools`: single tool with parameters, type casing (`string→STRING` etc.), empty tools returns empty array
+- [x] 4.3 Test `fromGeminiResponse`: text-only response → `{ content, toolCalls: undefined }`; function-call response → `toolCalls` with non-empty synthesized IDs; two calls produce different IDs
+- [x] 4.4 Test error paths: empty candidates → throws; SDK error → propagates
+- [x] 4.5 Add factory test to `apps/web/src/agent/providers/__tests__/index.test.ts`: `"gemini"` config → `GeminiAdapter` instance; unknown provider still throws
+- [x] 4.6 Test full `chat()` round-trip with mocked `GoogleGenerativeAI` — verify `generateContent` called with correct contents, tools, and systemInstruction
diff --git a/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/verify-report.md b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/verify-report.md
new file mode 100644
index 00000000..8f4d6e73
--- /dev/null
+++ b/openspec/changes/archive/2026-04-24-gemini-adapter-fase-1/verify-report.md
@@ -0,0 +1,116 @@
+# Verification Report
+
+**Change**: gemini-adapter-fase-1  
+**Version**: N/A  
+**Mode**: Standard
+
+---
+
+### Completeness
+
+| Metric | Value |
+|--------|-------|
+| Tasks total | 14 |
+| Tasks complete | 14 |
+| Tasks incomplete | 0 |
+
+All tasks in `openspec/changes/gemini-adapter-fase-1/tasks.md` are marked complete, including the post-verify fixes.
+
+---
+
+### Build & Tests Execution
+
+**Build**: ➖ Skipped
+
+```text
+No explicit `rules.verify.build_command` is configured in `openspec/config.yaml`.
+Project instructions also say never build after changes, so verification used TypeScript type-checking instead of `next build`.
+```
+
+**Type Check**: ✅ Passed
+
+```text
+Command: bunx tsc --noEmit
+
+(no output)
+```
+
+**Tests**: ✅ 48 passed / ❌ 0 failed / ⚠️ 0 skipped
+
+```text
+Command: bun test src/agent/providers/__tests__ src/app/api/agent/chat/__tests__/route.test.ts
+
+bun test v1.3.13
+48 pass
+0 fail
+106 expect() calls
+Ran 48 tests across 4 files.
+```
+
+**Coverage**: ➖ Not available
+
+---
+
+### Spec Compliance Matrix
+
+| Requirement | Scenario | Test | Result |
+|-------------|----------|------|--------|
+| Provider Adapter Interface | Adapter translates tool schemas to wire format | `src/agent/providers/__tests__/gemini.test.ts > converts a single tool with parameters` + `maps type strings to Gemini SchemaType values` | ✅ COMPLIANT |
+| Provider Adapter Interface | Adapter selected by config — OpenAI-compatible | `src/agent/providers/__tests__/index.test.ts > returns OpenAICompatibleAdapter for openai-compatible provider` | ✅ COMPLIANT |
+| Provider Adapter Interface | Adapter selected by config — Gemini | `src/agent/providers/__tests__/index.test.ts > returns GeminiAdapter for gemini provider` | ✅ COMPLIANT |
+| Provider Adapter Interface | Gemini adapter synthesizes tool-call IDs | `src/agent/providers/__tests__/gemini.test.ts > maps function-call response to toolCalls with non-empty synthesized IDs` | ✅ COMPLIANT |
+| Provider Configuration | Missing required configuration | `src/app/api/agent/chat/__tests__/route.test.ts > returns 502 when LLM_API_KEY is missing` | ✅ COMPLIANT |
+| Provider Configuration | Unknown provider | `src/agent/providers/__tests__/index.test.ts > throws Error for unknown provider` | ✅ COMPLIANT |
+| Provider Configuration | Gemini config ignores base URL | `src/agent/providers/__tests__/gemini.test.ts > ignores baseUrl in config — Gemini still works` | ✅ COMPLIANT |
+| Gemini Free-Form Chat | Plain chat through Gemini | `src/agent/providers/__tests__/gemini.test.ts > calls generateContent with correct contents and no tools` | ✅ COMPLIANT |
+| Gemini Free-Form Chat | System prompt mapping | `src/agent/providers/__tests__/gemini.test.ts > calls generateContent with correct contents and no tools` | ✅ COMPLIANT |
+| Gemini Tool Calling | Gemini returns function calls | `src/agent/providers/__tests__/gemini.test.ts > calls generateContent with tools and systemInstruction` | ✅ COMPLIANT |
+| Gemini Tool Calling | Gemini returns text despite tools | `src/agent/providers/__tests__/gemini.test.ts > returns text when tools are provided but Gemini responds with text only` | ✅ COMPLIANT |
+| Gemini Tool Calling | Tool schema type mapping | `src/agent/providers/__tests__/gemini.test.ts > maps type strings to Gemini SchemaType values` | ✅ COMPLIANT |
+
+**Compliance summary**: 12/12 scenarios compliant
+
+---
+
+### Correctness (Static — Structural Evidence)
+
+| Requirement | Status | Notes |
+|------------|--------|-------|
+| Provider Adapter Interface | ✅ Implemented | `apps/web/src/agent/providers/types.ts` keeps the provider-agnostic `chat()` seam, `index.ts` supports both providers, and `gemini.ts` synthesizes tool-call IDs with `crypto.randomUUID()`. |
+| Provider Configuration | ✅ Implemented | `apps/web/src/app/api/agent/chat/route.ts` reads `LLM_PROVIDER`, `LLM_API_KEY`, `LLM_MODEL`, and `LLM_BASE_URL` server-side only; `GeminiAdapter` intentionally ignores `baseUrl`. |
+| Gemini Free-Form Chat | ✅ Implemented | `GeminiAdapter.chat()` maps messages into Gemini contents, sets `systemInstruction` when present, and returns text-only responses without `toolCalls`. |
+| Gemini Tool Calling | ✅ Implemented | `toGeminiTools()` converts internal tool schemas to Gemini declarations and `fromGeminiResponse()` maps function-call parts back into provider `toolCalls`. |
+| Explicit non-goals remain deferred | ✅ Implemented | The touched files remain additive only; no streaming, multimodal upload, `@asset`, or contract changes were introduced. |
+
+---
+
+### Coherence (Design)
+
+| Decision | Followed? | Notes |
+|----------|-----------|-------|
+| Use `@google/generative-ai` SDK | ✅ Yes | Added in `apps/web/package.json`; adapter imports `GoogleGenerativeAI` and `SchemaType`. |
+| Preserve stateless provider seam | ✅ Yes | `GeminiAdapter.chat()` sends full history through one `generateContent()` call with no session state. |
+| Synthesize tool-call IDs inside adapter | ✅ Yes | `fromGeminiResponse()` generates IDs for Gemini function calls. |
+| Keep OpenAI-compatible path intact | ✅ Yes | `createProvider()` still returns `OpenAICompatibleAdapter` unchanged for the original provider. |
+| Map system prompt via Gemini-native field | ✅ Yes | `GeminiAdapter.chat()` sets `request.systemInstruction` instead of injecting a fake user message. |
+
+---
+
+### Issues Found
+
+**CRITICAL** (must fix before archive):
+None
+
+**WARNING** (should fix):
+None
+
+**SUGGESTION** (nice to have):
+None
+
+---
+
+### Verdict
+
+PASS
+
+All planned tasks are complete, the changed slice now type-checks, targeted runtime tests pass, and every spec scenario has passing behavioral evidence.
diff --git a/openspec/specs/agent-session-shell/spec.md b/openspec/specs/agent-session-shell/spec.md
index 1ddfac14..76727084 100644
--- a/openspec/specs/agent-session-shell/spec.md
+++ b/openspec/specs/agent-session-shell/spec.md
@@ -110,7 +110,7 @@ The system SHALL define types in `apps/web/src/agent/types.ts`: `ChatMessage { i
 
 ### Requirement: Provider Adapter Interface
 
-The system SHALL define a server-side provider adapter interface with a single method `chat(params: ProviderChatParams): Promise<ProviderChatResponse>`. `ProviderChatParams` MUST include `messages`, `systemPrompt`, and `toolSchemas` in a provider-agnostic internal format. `ProviderChatResponse` MUST include `content: string` and `toolCalls?: ProviderToolCall[]` where `ProviderToolCall { id, name, args }`. Each concrete adapter converts internal tool schemas to its own wire format. Phase 1 MAY ship exactly one adapter (OpenAI-compatible) as long as the interface contract remains provider-agnostic.
+The system SHALL define a server-side provider adapter interface with a single method `chat(params: ProviderChatParams): Promise<ProviderChatResponse>`. `ProviderChatParams` MUST include `messages`, `systemPrompt`, and `toolSchemas` in a provider-agnostic internal format. `ProviderChatResponse` MUST include `content: string` and `toolCalls?: ProviderToolCall[]` where `ProviderToolCall { id, name, args }`. Each concrete adapter converts internal tool schemas to its own wire format. The factory MUST support at least `openai-compatible` and `gemini` providers. Adapters whose native API does not assign IDs to tool calls MUST synthesize unique IDs so every returned `ToolCall.id` is a non-empty string.
 
 #### Scenario: Adapter translates tool schemas to wire format
 
@@ -118,15 +118,27 @@ The system SHALL define a server-side provider adapter interface with a single m
 - WHEN the adapter receives tool schemas before calling the provider
 - THEN it converts them to its provider-specific wire format
 
-#### Scenario: Adapter selected by config
+#### Scenario: Adapter selected by config — OpenAI-compatible
 
 - GIVEN `LLM_PROVIDER` is set to `"openai-compatible"`
 - WHEN the route resolves the adapter
 - THEN the OpenAI-compatible adapter is returned
 
+#### Scenario: Adapter selected by config — Gemini
+
+- GIVEN `LLM_PROVIDER` is set to `"gemini"`
+- WHEN the route resolves the adapter
+- THEN the Gemini adapter is returned
+
+#### Scenario: Gemini adapter synthesizes tool-call IDs
+
+- GIVEN the Gemini API returns a function call response with no call ID
+- WHEN the Gemini adapter maps the response to `ProviderResponse`
+- THEN each `ToolCall` in `toolCalls` has a non-empty `id` field generated by the adapter
+
 ### Requirement: Provider Configuration
 
-Server-only environment variables `LLM_PROVIDER` (required), `LLM_MODEL` (required), `LLM_API_KEY` (required), and `LLM_BASE_URL` (optional) MUST determine which adapter and model the route uses. Configuration MUST be read server-side only — never exposed to the client.
+Server-only environment variables `LLM_PROVIDER` (required), `LLM_MODEL` (required), `LLM_API_KEY` (required), and `LLM_BASE_URL` (optional) MUST determine which adapter and model the route uses. `LLM_PROVIDER` MUST accept at least `"openai-compatible"` and `"gemini"`. When `LLM_PROVIDER` is `"gemini"`, `LLM_BASE_URL` MUST be ignored. Configuration MUST be read server-side only — never exposed to the client.
 
 #### Scenario: Missing required configuration
 
@@ -134,6 +146,18 @@ Server-only environment variables `LLM_PROVIDER` (required), `LLM_MODEL` (requir
 - WHEN the route attempts to initialize the provider
 - THEN the call returns 502 with a missing-configuration error
 
+#### Scenario: Unknown provider
+
+- GIVEN `LLM_PROVIDER` is set to `"unknown-provider"`
+- WHEN the route resolves the adapter
+- THEN the factory throws `"Unknown LLM provider: unknown-provider"`
+
+#### Scenario: Gemini config ignores base URL
+
+- GIVEN `LLM_PROVIDER` is `"gemini"` and `LLM_BASE_URL` is set
+- WHEN the Gemini adapter is created
+- THEN `LLM_BASE_URL` is not used in the API call
+
 ### Requirement: Tool Argument Validation
 
 Before executing any tool call, the orchestrator MUST validate that each argument key declared `required: true` in the tool's `parameters` is present in the call args and is of the declared type. If validation fails, the tool MUST NOT execute; instead the orchestrator MUST produce a `ToolResult` with `error` describing the missing or malformed argument.
@@ -166,3 +190,41 @@ The orchestrator loop MUST enforce a hard iteration cap of **8**. An iteration i
 - GIVEN the provider returns a final text response after 2 tool-call iterations
 - WHEN the orchestrator processes the response
 - THEN no cap message is appended and status is `"idle"`
+
+### Requirement: Gemini Free-Form Chat
+
+When the Gemini adapter receives a request with no tool schemas (or tools array is empty), it MUST send messages to the Gemini `generateContent` API and return a `ProviderResponse` with `content` set to the assistant text and `toolCalls` undefined.
+
+#### Scenario: Plain chat through Gemini
+
+- GIVEN `LLM_PROVIDER` is `"gemini"` and messages contain `[{ role: "user", content: "Hello" }]`
+- WHEN the adapter calls Gemini and receives a text-only response
+- THEN `ProviderResponse.content` is the assistant text and `toolCalls` is undefined
+
+#### Scenario: System prompt mapping
+
+- GIVEN the adapter receives `systemPrompt: "You are a video editor"`
+- WHEN it builds the Gemini request
+- THEN the system prompt is mapped to Gemini's system instruction field, not as a user message
+
+### Requirement: Gemini Tool Calling
+
+When the Gemini adapter receives a request with tool schemas, it MUST convert internal `ToolSchema[]` to Gemini function declarations, call `generateContent` with declarations attached, and if Gemini returns function call parts, map each to a `ToolCall { id, name, args }` with a synthesized non-empty `id`.
+
+#### Scenario: Gemini returns function calls
+
+- GIVEN `transcribe_video` is in tool schemas and Gemini responds with a function call part `{ name: "transcribe_video", args: {} }`
+- WHEN the adapter maps the response
+- THEN `toolCalls` contains one `ToolCall` with `name: "transcribe_video"`, `args: {}`, and a synthesized `id`
+
+#### Scenario: Gemini returns text despite tools
+
+- GIVEN tool schemas are provided but Gemini responds with only text
+- WHEN the adapter maps the response
+- THEN `toolCalls` is undefined and `content` holds the text
+
+#### Scenario: Tool schema type mapping
+
+- GIVEN an internal tool schema has parameters `[{ key: "assetId", type: "string", required: true }]`
+- WHEN the adapter converts to Gemini function declarations
+- THEN the parameter appears in `FunctionDeclaration.parameters.properties` with type `"string"`