diff --git a/packages/plugins/official/ai-chat-widget/__tests__/index.test.ts b/packages/plugins/official/ai-chat-widget/__tests__/index.test.ts
new file mode 100644
index 0000000..c4d8341
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/__tests__/index.test.ts
@@ -0,0 +1,565 @@
+/// <reference types="jest" />
+/**
+ * AI Chat Widget — Unit Tests
+ */
+import plugin, {
+  generateSessionId,
+  buildSessionKey,
+  buildActiveKey,
+  trimMessages,
+  ChatSession,
+  ChatMessage,
+  DEFAULT_MODEL,
+  DEFAULT_MAX_HISTORY,
+  SUPPORTED_MODELS,
+} from "../src/index";
+import {
+  PluginContext,
+  PluginAPI,
+  PluginDatabaseAPI,
+  PluginEventBus,
+  EndpointDefinition,
+  EndpointRequest,
+} from "@agentbase/plugin-sdk";
+
+// ── Mock factory ─────────────────────────────────────────────────────────────
+
+function createMockAPI(): PluginAPI & { _endpoints: EndpointDefinition[] } {
+  const store = new Map<string, any>();
+  const _endpoints: EndpointDefinition[] = [];
+
+  const db: PluginDatabaseAPI = {
+    set: jest
+      .fn()
+      .mockImplementation(async (k: string, v: any) => store.set(k, v)),
+    get: jest
+      .fn()
+      .mockImplementation(async (k: string) => store.get(k) ?? null),
+    delete: jest.fn().mockImplementation(async (k: string) => {
+      const had = store.has(k);
+      store.delete(k);
+      return had;
+    }),
+    keys: jest
+      .fn()
+      .mockImplementation(async (prefix?: string) =>
+        [...store.keys()].filter((k) => !prefix || k.startsWith(prefix)),
+      ),
+    find: jest.fn().mockResolvedValue([]),
+    count: jest.fn().mockResolvedValue(0),
+  };
+
+  const events: PluginEventBus = {
+    emit: jest.fn().mockResolvedValue(undefined),
+    on: jest.fn(),
+    off: jest.fn(),
+  };
+
+  const api = {
+    _endpoints,
+    getConfig: jest.fn().mockReturnValue(undefined),
+    setConfig: jest.fn().mockResolvedValue(undefined),
+    makeRequest: jest.fn().mockResolvedValue({ ok: true, status: 200 }),
+    log: jest.fn(),
+    db,
+    events,
+    registerEndpoint: jest
+      .fn()
+      .mockImplementation((def: EndpointDefinition) => _endpoints.push(def)),
+    registerCronJob: jest.fn(),
+    registerWebhook: jest.fn(),
+    registerAdminPage: jest.fn(),
+  } as unknown as PluginAPI & { _endpoints: EndpointDefinition[] };
+
+  return api;
+}
+
+function makeCtx(
+  overrides: Partial<PluginContext> = {},
+): PluginContext & { api: ReturnType<typeof createMockAPI> } {
+  return {
+    appId: "app1",
+    userId: "user1",
+    config: {},
+    api: createMockAPI(),
+    ...overrides,
+  } as any;
+}
+
+/** Run app:init and return the registered endpoints array. */
+async function initEndpoints(ctx: ReturnType<typeof makeCtx>) {
+  await plugin.definition.hooks!["app:init"]!(ctx);
+  return ctx.api._endpoints;
+}
+
+function makeRes() {
+  const res = {
+    _status: 200,
+    _data: undefined as any,
+    status(code: number) {
+      this._status = code;
+      return this;
+    },
+    json(data: any) {
+      this._data = data;
+    },
+    send(data: string) {
+      this._data = data;
+    },
+  };
+  return res;
+}
+
+function fakeReq(override: Partial<EndpointRequest> = {}): EndpointRequest {
+  return {
+    method: "GET",
+    path: "/",
+    params: {},
+    query: {},
+    body: {},
+    headers: {},
+    ...override,
+  };
+}
+
+// ── Helper function unit tests ────────────────────────────────────────────────
+
+describe("generateSessionId", () => {
+  it("returns a non-empty string", () => {
+    expect(typeof generateSessionId()).toBe("string");
+    expect(generateSessionId().length).toBeGreaterThan(0);
+  });
+
+  it("generates unique values", () => {
+    const ids = new Set(Array.from({ length: 50 }, generateSessionId));
+    expect(ids.size).toBe(50);
+  });
+});
+
+describe("buildSessionKey", () => {
+  it("prefixes with session:", () => {
+    expect(buildSessionKey("abc")).toBe("session:abc");
+  });
+});
+
+describe("buildActiveKey", () => {
+  it("builds composite key", () => {
+    expect(buildActiveKey("app1", "user1")).toBe("active:app1:user1");
+  });
+});
+
+describe("trimMessages", () => {
+  const msg = (n: number): ChatMessage => ({
+    role: "user",
+    content: `m${n}`,
+    ts: n,
+  });
+
+  it("returns array unchanged when under limit", () => {
+    const msgs = [msg(1), msg(2)];
+    expect(trimMessages(msgs, 5)).toEqual(msgs);
+  });
+
+  it("trims from the oldest end when over limit", () => {
+    const msgs = [msg(1), msg(2), msg(3), msg(4), msg(5)];
+    const result = trimMessages(msgs, 3);
+    expect(result).toHaveLength(3);
+    expect(result[0].content).toBe("m3");
+    expect(result[2].content).toBe("m5");
+  });
+
+  it("returns unchanged when exactly at limit", () => {
+    const msgs = [msg(1), msg(2), msg(3)];
+    expect(trimMessages(msgs, 3)).toHaveLength(3);
+  });
+
+  it("returns unchanged when maxHistory is 0 (disabled)", () => {
+    const msgs = [msg(1), msg(2)];
+    expect(trimMessages(msgs, 0)).toEqual(msgs);
+  });
+});
+
+// ── Plugin structure ──────────────────────────────────────────────────────────
+
+describe("plugin definition", () => {
+  it("has correct name and version", () => {
+    expect(plugin.definition.name).toBe("ai-chat-widget");
+    expect(plugin.definition.version).toBe("1.0.0");
+  });
+
+  it("defines all four settings with correct types", () => {
+    const s = plugin.definition.settings!;
+    expect(s.systemPrompt.type).toBe("string");
+    expect(s.model.type).toBe("select");
+    expect(s.model.options).toEqual([...SUPPORTED_MODELS]);
+    expect(s.model.default).toBe(DEFAULT_MODEL);
+    expect(s.streamingEnabled.type).toBe("boolean");
+    expect(s.streamingEnabled.default).toBe(true);
+    expect(s.maxHistory.type).toBe("number");
+    expect(s.maxHistory.default).toBe(DEFAULT_MAX_HISTORY);
+  });
+
+  it("defines hooks for all four lifecycle events", () => {
+    const h = Object.keys(plugin.definition.hooks!);
+    expect(h).toContain("app:init");
+    expect(h).toContain("conversation:start");
+    expect(h).toContain("conversation:beforeMessage");
+    expect(h).toContain("conversation:end");
+  });
+
+  it("defines filters for prompt:modify and response:modify", () => {
+    const f = Object.keys(plugin.definition.filters!);
+    expect(f).toContain("prompt:modify");
+    expect(f).toContain("response:modify");
+  });
+});
+
+// ── app:init hook ─────────────────────────────────────────────────────────────
+
+describe("app:init hook", () => {
+  it("registers exactly 4 endpoints", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    expect(eps).toHaveLength(4);
+  });
+
+  it("registers the expected method+path combinations", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    const signatures = eps.map((e) => `${e.method} ${e.path}`);
+    expect(signatures).toContain("GET /config");
+    expect(signatures).toContain("POST /session");
+    expect(signatures).toContain("GET /session/:id");
+    expect(signatures).toContain("DELETE /session/:id");
+  });
+
+  it("marks all endpoints as auth: true", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    expect(eps.every((e) => e.auth === true)).toBe(true);
+  });
+});
+
+// ── conversation:start hook ───────────────────────────────────────────────────
+
+describe("conversation:start hook", () => {
+  it("writes a session record and an active key", async () => {
+    const ctx = makeCtx();
+    await plugin.definition.hooks!["conversation:start"]!(ctx, {});
+
+    const setCalls = (ctx.api.db.set as jest.Mock).mock.calls;
+    expect(setCalls).toHaveLength(2);
+
+    const sessionCall = setCalls.find(([k]) => k.startsWith("session:"));
+    const activeCall = setCalls.find(([k]) => k.startsWith("active:"));
+    expect(sessionCall).toBeDefined();
+    expect(activeCall).toBeDefined();
+  });
+
+  it("session record contains correct appId, userId and empty messages", async () => {
+    const ctx = makeCtx({ appId: "myapp", userId: "myuser" });
+    await plugin.definition.hooks!["conversation:start"]!(ctx, {});
+
+    const setCalls = (ctx.api.db.set as jest.Mock).mock.calls;
+    const session: ChatSession = setCalls.find(([k]) =>
+      k.startsWith("session:"),
+    )[1];
+
+    expect(session.appId).toBe("myapp");
+    expect(session.userId).toBe("myuser");
+    expect(session.messages).toEqual([]);
+  });
+
+  it("active key encodes appId and userId", async () => {
+    const ctx = makeCtx({ appId: "myapp", userId: "myuser" });
+    await plugin.definition.hooks!["conversation:start"]!(ctx, {});
+
+    const setCalls = (ctx.api.db.set as jest.Mock).mock.calls;
+    const [activeKey] = setCalls.find(([k]) => k.startsWith("active:"));
+    expect(activeKey).toBe("active:myapp:myuser");
+  });
+});
+
+// ── conversation:beforeMessage hook ──────────────────────────────────────────
+
+describe("conversation:beforeMessage hook", () => {
+  it("does nothing when no active session exists", async () => {
+    const ctx = makeCtx();
+    // db.get returns null for everything (default mock)
+    await plugin.definition.hooks!["conversation:beforeMessage"]!(ctx, {
+      content: "hello",
+      role: "user",
+    });
+    expect(ctx.api.db.set).not.toHaveBeenCalled();
+  });
+
+  it("appends the incoming message to the session", async () => {
+    const ctx = makeCtx();
+    const sessionId = "s1";
+    const session: ChatSession = {
+      id: sessionId,
+      appId: "app1",
+      userId: "user1",
+      messages: [],
+      model: DEFAULT_MODEL,
+      createdAt: 0,
+      updatedAt: 0,
+    };
+    await ctx.api.db.set(buildActiveKey("app1", "user1"), sessionId);
+    await ctx.api.db.set(buildSessionKey(sessionId), session);
+    (ctx.api.db.set as jest.Mock).mockClear();
+
+    await plugin.definition.hooks!["conversation:beforeMessage"]!(ctx, {
+      content: "Hello",
+      role: "user",
+    });
+
+    expect(ctx.api.db.set).toHaveBeenCalledWith(
+      buildSessionKey(sessionId),
+      expect.objectContaining({
+        messages: expect.arrayContaining([
+          expect.objectContaining({ content: "Hello", role: "user" }),
+        ]),
+      }),
+    );
+  });
+
+  it("trims messages to maxHistory", async () => {
+    const ctx = makeCtx();
+    (ctx.api.getConfig as jest.Mock).mockImplementation((k: string) =>
+      k === "maxHistory" ? 2 : undefined,
+    );
+
+    const sessionId = "s2";
+    const existing: ChatMessage[] = [
+      { role: "user", content: "a", ts: 1 },
+      { role: "assistant", content: "b", ts: 2 },
+    ];
+    const session: ChatSession = {
+      id: sessionId,
+      appId: "app1",
+      userId: "user1",
+      messages: existing,
+      model: DEFAULT_MODEL,
+      createdAt: 0,
+      updatedAt: 0,
+    };
+    await ctx.api.db.set(buildActiveKey("app1", "user1"), sessionId);
+    await ctx.api.db.set(buildSessionKey(sessionId), session);
+    (ctx.api.db.set as jest.Mock).mockClear();
+
+    await plugin.definition.hooks!["conversation:beforeMessage"]!(ctx, {
+      content: "c",
+      role: "user",
+    });
+
+    const saved = (ctx.api.db.set as jest.Mock).mock.calls[0][1] as ChatSession;
+    expect(saved.messages).toHaveLength(2);
+    expect(saved.messages[0].content).toBe("b");
+    expect(saved.messages[1].content).toBe("c");
+  });
+});
+
+// ── conversation:end hook ─────────────────────────────────────────────────────
+
+describe("conversation:end hook", () => {
+  it("does nothing when no active session", async () => {
+    const ctx = makeCtx();
+    await plugin.definition.hooks!["conversation:end"]!(ctx);
+    expect(ctx.api.db.set).not.toHaveBeenCalled();
+  });
+
+  it("updates updatedAt and removes the active key", async () => {
+    const ctx = makeCtx();
+    const sessionId = "send1";
+    const session: ChatSession = {
+      id: sessionId,
+      appId: "app1",
+      userId: "user1",
+      messages: [],
+      model: DEFAULT_MODEL,
+      createdAt: 1000,
+      updatedAt: 1000,
+    };
+    await ctx.api.db.set(buildActiveKey("app1", "user1"), sessionId);
+    await ctx.api.db.set(buildSessionKey(sessionId), session);
+    (ctx.api.db.set as jest.Mock).mockClear();
+
+    await plugin.definition.hooks!["conversation:end"]!(ctx);
+
+    expect(ctx.api.db.set).toHaveBeenCalledWith(
+      buildSessionKey(sessionId),
+      expect.objectContaining({ updatedAt: expect.any(Number) }),
+    );
+    expect(ctx.api.db.delete).toHaveBeenCalledWith(
+      buildActiveKey("app1", "user1"),
+    );
+  });
+});
+
+// ── prompt:modify filter ──────────────────────────────────────────────────────
+
+describe("prompt:modify filter", () => {
+  it("prepends system prompt to string prompts", async () => {
+    const ctx = makeCtx();
+    (ctx.api.getConfig as jest.Mock).mockImplementation((k: string) =>
+      k === "systemPrompt" ? "Be concise." : undefined,
+    );
+    const result = await plugin.definition.filters!["prompt:modify"]!(
+      ctx,
+      "Tell me a joke",
+    );
+    expect(result).toBe("Be concise.\n\nTell me a joke");
+  });
+
+  it("returns prompt unchanged when system prompt is empty", async () => {
+    const ctx = makeCtx();
+    (ctx.api.getConfig as jest.Mock).mockReturnValue("");
+    expect(
+      await plugin.definition.filters!["prompt:modify"]!(ctx, "Hello"),
+    ).toBe("Hello");
+  });
+
+  it("returns non-string values unchanged regardless of system prompt", async () => {
+    const ctx = makeCtx();
+    (ctx.api.getConfig as jest.Mock).mockReturnValue("system");
+    const obj = { type: "structured" };
+    expect(await plugin.definition.filters!["prompt:modify"]!(ctx, obj)).toBe(
+      obj,
+    );
+  });
+});
+
+// ── response:modify filter ────────────────────────────────────────────────────
+
+describe("response:modify filter", () => {
+  it("injects _widget field into object responses", async () => {
+    const ctx = makeCtx();
+    const result = await plugin.definition.filters!["response:modify"]!(ctx, {
+      text: "hello",
+    });
+    expect(result).toEqual({ text: "hello", _widget: "ai-chat-widget" });
+  });
+
+  it("leaves string responses unchanged", async () => {
+    const ctx = makeCtx();
+    expect(
+      await plugin.definition.filters!["response:modify"]!(ctx, "raw string"),
+    ).toBe("raw string");
+  });
+
+  it("leaves null unchanged", async () => {
+    const ctx = makeCtx();
+    expect(
+      await plugin.definition.filters!["response:modify"]!(ctx, null),
+    ).toBeNull();
+  });
+});
+
+// ── Endpoint handlers ─────────────────────────────────────────────────────────
+
+describe("endpoint handlers (via app:init closure)", () => {
+  it("GET /config returns widget config values", async () => {
+    const ctx = makeCtx();
+    (ctx.api.getConfig as jest.Mock).mockImplementation((k: string) => {
+      const cfg: Record<string, any> = {
+        model: "gpt-4o",
+        streamingEnabled: false,
+        maxHistory: 10,
+      };
+      return cfg[k];
+    });
+    const [ep] = (await initEndpoints(ctx)).filter(
+      (e) => e.method === "GET" && e.path === "/config",
+    );
+    const res = makeRes();
+    await ep.handler(fakeReq(), res);
+    expect(res._data.widgetId).toBe("ai-chat-widget");
+    expect(res._data.model).toBe("gpt-4o");
+    expect(res._data.streamingEnabled).toBe(false);
+    expect(res._data.maxHistory).toBe(10);
+  });
+
+  it("POST /session creates and returns a session with status 201", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    const ep = eps.find((e) => e.method === "POST" && e.path === "/session")!;
+    const res = makeRes();
+    await ep.handler(
+      fakeReq({
+        method: "POST",
+        path: "/session",
+        user: { id: "u42", email: "u@x.com", role: "user" },
+      }),
+      res,
+    );
+    expect(res._status).toBe(201);
+    expect(res._data).toMatchObject({
+      id: expect.any(String),
+      userId: "u42",
+      appId: "app1",
+      messages: [],
+    });
+  });
+
+  it("GET /session/:id returns 404 when session does not exist", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    const ep = eps.find(
+      (e) => e.method === "GET" && e.path === "/session/:id",
+    )!;
+    const res = makeRes();
+    await ep.handler(fakeReq({ params: { id: "ghost" } }), res);
+    expect(res._status).toBe(404);
+    expect(res._data.error).toBeDefined();
+  });
+
+  it("GET /session/:id returns the session when it exists", async () => {
+    const ctx = makeCtx();
+    const session: ChatSession = {
+      id: "s99",
+      appId: "app1",
+      userId: "user1",
+      messages: [],
+      model: DEFAULT_MODEL,
+      createdAt: 0,
+      updatedAt: 0,
+    };
+    await ctx.api.db.set(buildSessionKey("s99"), session);
+
+    const eps = await initEndpoints(ctx);
+    const ep = eps.find(
+      (e) => e.method === "GET" && e.path === "/session/:id",
+    )!;
+    const res = makeRes();
+    await ep.handler(fakeReq({ params: { id: "s99" } }), res);
+    expect(res._data).toMatchObject({ id: "s99" });
+  });
+
+  it("DELETE /session/:id returns 404 when session does not exist", async () => {
+    const ctx = makeCtx();
+    const eps = await initEndpoints(ctx);
+    const ep = eps.find(
+      (e) => e.method === "DELETE" && e.path === "/session/:id",
+    )!;
+    const res = makeRes();
+    await ep.handler(fakeReq({ params: { id: "ghost" } }), res);
+    expect(res._status).toBe(404);
+  });
+
+  it("DELETE /session/:id deletes the session and returns 204", async () => {
+    const ctx = makeCtx();
+    await ctx.api.db.set(buildSessionKey("del1"), { id: "del1" });
+
+    const eps = await initEndpoints(ctx);
+    const ep = eps.find(
+      (e) => e.method === "DELETE" && e.path === "/session/:id",
+    )!;
+    const res = makeRes();
+    await ep.handler(fakeReq({ params: { id: "del1" } }), res);
+    expect(res._status).toBe(204);
+
+    // Confirm removed from store
+    expect(await ctx.api.db.get(buildSessionKey("del1"))).toBeNull();
+  });
+});
diff --git a/packages/plugins/official/ai-chat-widget/__tests__/tsconfig.json b/packages/plugins/official/ai-chat-widget/__tests__/tsconfig.json
new file mode 100644
index 0000000..71edfea
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/__tests__/tsconfig.json
@@ -0,0 +1,20 @@
+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "lib": ["ES2022", "DOM"],
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "noEmit": true,
+    "rootDir": "../../../",
+    "types": ["jest"],
+    "paths": {
+      "@agentbase/plugin-sdk": ["../../sdk/src/index.ts"]
+    }
+  },
+  "include": ["**/*.ts", "../src/**/*.ts"],
+  "exclude": ["node_modules"]
+}
diff --git a/packages/plugins/official/ai-chat-widget/manifest.json b/packages/plugins/official/ai-chat-widget/manifest.json
new file mode 100644
index 0000000..e174f09
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/manifest.json
@@ -0,0 +1,10 @@
+{
+  "name": "ai-chat-widget",
+  "version": "1.0.0",
+  "description": "Embeddable chat interface with streaming, multi-model support, and session management.",
+  "entryPoint": "dist/index.js",
+  "author": "Agentbase Team",
+  "agentbaseVersion": ">=1.0.0",
+  "permissions": [],
+  "peerDependencies": {}
+}
diff --git a/packages/plugins/official/ai-chat-widget/package.json b/packages/plugins/official/ai-chat-widget/package.json
new file mode 100644
index 0000000..c1e49c9
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/package.json
@@ -0,0 +1,40 @@
+{
+  "name": "@agentbase/plugin-ai-chat-widget",
+  "version": "1.0.0",
+  "description": "Embeddable chat interface with streaming, multi-model support, and session management.",
+  "private": true,
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "license": "GPL-3.0-or-later",
+  "scripts": {
+    "build": "tsc",
+    "test": "jest --passWithNoTests",
+    "test:cov": "jest --coverage --passWithNoTests"
+  },
+  "dependencies": {
+    "@agentbase/plugin-sdk": "workspace:*"
+  },
+  "devDependencies": {
+    "@types/jest": "^29.5.0",
+    "jest": "^29.7.0",
+    "ts-jest": "^29.2.0",
+    "typescript": "^5.7.0"
+  },
+  "jest": {
+    "preset": "ts-jest",
+    "testEnvironment": "node",
+    "testMatch": [
+      "**/__tests__/**/*.test.ts"
+    ],
+    "globals": {
+      "ts-jest": {
+        "tsconfig": "./tsconfig.test.json"
+      }
+    },
+    "coverageThreshold": {
+      "global": {
+        "lines": 80
+      }
+    }
+  }
+}
diff --git a/packages/plugins/official/ai-chat-widget/src/index.ts b/packages/plugins/official/ai-chat-widget/src/index.ts
new file mode 100644
index 0000000..8160f13
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/src/index.ts
@@ -0,0 +1,318 @@
+/**
+ * AI Chat Widget
+ *
+ * Embeddable chat interface with streaming, multi-model support, and session
+ * management. Sessions are stored in the plugin's scoped database (MongoDB-backed
+ * KV store). The system prompt and model settings are configurable per-application.
+ *
+ * @package @agentbase/plugin-ai-chat-widget
+ * @version 1.0.0
+ */
+import { createPlugin, PluginContext } from "@agentbase/plugin-sdk";
+
+// ── Constants ─────────────────────────────────────────────────────────────────
+
+export const SUPPORTED_MODELS = [
+  "gpt-4o",
+  "claude-3-5-sonnet",
+  "gemini-2-0-flash",
+] as const;
+
+export type SupportedModel = (typeof SUPPORTED_MODELS)[number];
+
+export const DEFAULT_MODEL: SupportedModel = "gpt-4o";
+export const DEFAULT_MAX_HISTORY = 20;
+
+// ── Types ─────────────────────────────────────────────────────────────────────
+
+export interface ChatMessage {
+  role: "user" | "assistant" | "system";
+  content: string;
+  ts: number;
+}
+
+export interface ChatSession {
+  id: string;
+  appId: string;
+  userId: string;
+  messages: ChatMessage[];
+  model: string;
+  createdAt: number;
+  updatedAt: number;
+}
+
+// ── Helpers ───────────────────────────────────────────────────────────────────
+
+/** Generate a random session ID using timestamp + random component. */
+export function generateSessionId(): string {
+  return Date.now().toString(36) + Math.random().toString(36).slice(2, 9);
+}
+
+/** Plugin DB key for a session record. */
+export function buildSessionKey(sessionId: string): string {
+  return `session:${sessionId}`;
+}
+
+/** Plugin DB key tracking the active session for an app+user pair. */
+export function buildActiveKey(appId: string, userId: string): string {
+  return `active:${appId}:${userId}`;
+}
+
+/**
+ * Keep only the most recent `maxHistory` messages, dropping from the oldest end.
+ * If maxHistory is 0 (or negative), returns the array unchanged.
+ */
+export function trimMessages(
+  messages: ChatMessage[],
+  maxHistory: number,
+): ChatMessage[] {
+  if (maxHistory <= 0 || messages.length <= maxHistory) return messages;
+  return messages.slice(messages.length - maxHistory);
+}
+
+// ── Plugin ────────────────────────────────────────────────────────────────────
+
+export default createPlugin({
+  name: "ai-chat-widget",
+  version: "1.0.0",
+  description:
+    "Embeddable chat interface with streaming, multi-model support, and session management.",
+  author: "Agentbase Team",
+
+  // ── Settings ───────────────────────────────────────────────────────────────
+  settings: {
+    systemPrompt: {
+      type: "string",
+      label: "System Prompt",
+      default: "",
+    },
+    model: {
+      type: "select",
+      label: "AI Model",
+      options: [...SUPPORTED_MODELS],
+      default: DEFAULT_MODEL,
+    },
+    streamingEnabled: {
+      type: "boolean",
+      label: "Enable Streaming Responses",
+      default: true,
+    },
+    maxHistory: {
+      type: "number",
+      label: "Max Message History (per session)",
+      default: DEFAULT_MAX_HISTORY,
+    },
+  },
+
+  // ── Hooks ──────────────────────────────────────────────────────────────────
+  hooks: {
+    /**
+     * app:init — register the four session endpoints.
+     * Endpoint handlers close over `context` to access the plugin DB.
+     */
+    "app:init": async (context: PluginContext) => {
+      context.api.log("AI Chat Widget initialized");
+
+      // GET /config — return public plugin configuration
+      context.api.registerEndpoint({
+        method: "GET",
+        path: "/config",
+        auth: true,
+        description: "Return public plugin configuration",
+        handler: async (_req, res) => {
+          res.json({
+            widgetId: "ai-chat-widget",
+            model: (context.api.getConfig("model") as string) ?? DEFAULT_MODEL,
+            streamingEnabled:
+              (context.api.getConfig("streamingEnabled") as boolean) ?? true,
+            maxHistory:
+              (context.api.getConfig("maxHistory") as number) ??
+              DEFAULT_MAX_HISTORY,
+          });
+        },
+      });
+
+      // POST /session — create a new chat session
+      context.api.registerEndpoint({
+        method: "POST",
+        path: "/session",
+        auth: true,
+        description: "Create a new chat session",
+        handler: async (req, res) => {
+          const userId = req.user?.id ?? "anonymous";
+          const session: ChatSession = {
+            id: generateSessionId(),
+            appId: context.appId,
+            userId,
+            messages: [],
+            model: (context.api.getConfig("model") as string) ?? DEFAULT_MODEL,
+            createdAt: Date.now(),
+            updatedAt: Date.now(),
+          };
+          await context.api.db.set(buildSessionKey(session.id), session);
+          res.status(201).json(session);
+        },
+      });
+
+      // GET /session/:id — retrieve a session by ID
+      context.api.registerEndpoint({
+        method: "GET",
+        path: "/session/:id",
+        auth: true,
+        description: "Retrieve a chat session by ID",
+        handler: async (req, res) => {
+          const session = (await context.api.db.get(
+            buildSessionKey(req.params.id),
+          )) as ChatSession | null;
+          if (!session) {
+            res.status(404).json({ error: "Session not found" });
+            return;
+          }
+          res.json(session);
+        },
+      });
+
+      // DELETE /session/:id — delete a session
+      context.api.registerEndpoint({
+        method: "DELETE",
+        path: "/session/:id",
+        auth: true,
+        description: "Delete a chat session",
+        handler: async (req, res) => {
+          const deleted = await context.api.db.delete(
+            buildSessionKey(req.params.id),
+          );
+          if (!deleted) {
+            res.status(404).json({ error: "Session not found" });
+            return;
+          }
+          res.status(204).send("");
+        },
+      });
+    },
+
+    /**
+     * conversation:start — create a session and mark it as active for this
+     * app+user pair. The active key is used by subsequent hooks to look up the
+     * session without scanning all keys.
+     */
+    "conversation:start": async (
+      context: PluginContext,
+      _conversation: { id?: string },
+    ) => {
+      const sessionId = generateSessionId();
+      const session: ChatSession = {
+        id: sessionId,
+        appId: context.appId,
+        userId: context.userId,
+        messages: [],
+        model: (context.api.getConfig("model") as string) ?? DEFAULT_MODEL,
+        createdAt: Date.now(),
+        updatedAt: Date.now(),
+      };
+      await context.api.db.set(buildSessionKey(sessionId), session);
+      await context.api.db.set(
+        buildActiveKey(context.appId, context.userId),
+        sessionId,
+      );
+      context.api.log(
+        `Session created for user ${context.userId}: ${sessionId}`,
+      );
+    },
+
+    /**
+     * conversation:beforeMessage — append the incoming message to the active
+     * session and trim the history to stay within the maxHistory limit.
+     */
+    "conversation:beforeMessage": async (
+      context: PluginContext,
+      message: { content?: string; role?: string },
+    ) => {
+      const sessionId = (await context.api.db.get(
+        buildActiveKey(context.appId, context.userId),
+      )) as string | null;
+      if (!sessionId) return;
+
+      const session = (await context.api.db.get(
+        buildSessionKey(sessionId),
+      )) as ChatSession | null;
+      if (!session) return;
+
+      const maxHistory =
+        (context.api.getConfig("maxHistory") as number) ?? DEFAULT_MAX_HISTORY;
+
+      const newMessage: ChatMessage = {
+        role: (message.role as ChatMessage["role"]) ?? "user",
+        content: message.content ?? "",
+        ts: Date.now(),
+      };
+
+      const messages = trimMessages(
+        [...session.messages, newMessage],
+        maxHistory,
+      );
+
+      await context.api.db.set(buildSessionKey(sessionId), {
+        ...session,
+        messages,
+        updatedAt: Date.now(),
+      });
+    },
+
+    /**
+     * conversation:end — stamp the session with the end time and remove the
+     * active key so future messages start a fresh session.
+     */
+    "conversation:end": async (context: PluginContext) => {
+      const sessionId = (await context.api.db.get(
+        buildActiveKey(context.appId, context.userId),
+      )) as string | null;
+      if (!sessionId) return;
+
+      const session = (await context.api.db.get(
+        buildSessionKey(sessionId),
+      )) as ChatSession | null;
+
+      if (session) {
+        await context.api.db.set(buildSessionKey(sessionId), {
+          ...session,
+          updatedAt: Date.now(),
+        });
+      }
+
+      await context.api.db.delete(
+        buildActiveKey(context.appId, context.userId),
+      );
+    },
+  },
+
+  // ── Filters ────────────────────────────────────────────────────────────────
+  filters: {
+    /**
+     * prompt:modify — prepend the configured system prompt to every prompt
+     * string, ensuring the LLM respects the widget's persona/instructions.
+     */
+    "prompt:modify": async (context: PluginContext, value: unknown) => {
+      const systemPrompt =
+        (context.api.getConfig("systemPrompt") as string) ?? "";
+      if (systemPrompt && typeof value === "string" && value.trim()) {
+        return `${systemPrompt}\n\n${value}`;
+      }
+      return value;
+    },
+
+    /**
+     * response:modify — tag every object response with the widget identifier
+     * so clients can distinguish widget-originated responses.
+     */
+    "response:modify": async (_context: PluginContext, value: unknown) => {
+      if (value !== null && typeof value === "object") {
+        return {
+          ...(value as Record<string, unknown>),
+          _widget: "ai-chat-widget",
+        };
+      }
+      return value;
+    },
+  },
+});
diff --git a/packages/plugins/official/ai-chat-widget/tsconfig.json b/packages/plugins/official/ai-chat-widget/tsconfig.json
new file mode 100644
index 0000000..1ec1969
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/tsconfig.json
@@ -0,0 +1,20 @@
+{
+  "extends": "../../../../tsconfig.json",
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "outDir": "./dist",
+    "rootDir": "../..",
+    "baseUrl": ".",
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true,
+    "strict": true,
+    "noEmit": true,
+    "paths": {
+      "@agentbase/plugin-sdk": ["../../sdk/src/index.ts"]
+    }
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist", "__tests__"]
+}
diff --git a/packages/plugins/official/ai-chat-widget/tsconfig.test.json b/packages/plugins/official/ai-chat-widget/tsconfig.test.json
new file mode 100644
index 0000000..4437ff8
--- /dev/null
+++ b/packages/plugins/official/ai-chat-widget/tsconfig.test.json
@@ -0,0 +1,14 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "../..",
+    "baseUrl": ".",
+    "lib": ["ES2022", "DOM"],
+    "types": ["jest"],
+    "paths": {
+      "@agentbase/plugin-sdk": ["../../sdk/src/index.ts"]
+    }
+  },
+  "include": ["src/**/*", "__tests__/**/*"],
+  "exclude": ["node_modules", "dist"]
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 1bd92c5..c9ab522 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -178,7 +178,7 @@ importers:
         version: 7.2.2
       ts-jest:
         specifier: ^29.2.0
-        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3)
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
       ts-node:
         specifier: ^10.9.0
         version: 10.9.2(@types/node@22.19.11)(typescript@5.9.3)
@@ -284,7 +284,7 @@ importers:
         version: 1.0.7(tailwindcss@3.4.19)
       ts-jest:
         specifier: ^29.4.6
-        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3)
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
       typescript:
         specifier: ^5.7.0
         version: 5.9.3
@@ -354,7 +354,7 @@ importers:
         version: 29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3))
       ts-jest:
         specifier: ^29.4.6
-        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3)
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
       ts-node:
         specifier: ^10.9.2
         version: 10.9.2(@types/node@22.19.11)(typescript@5.9.3)
@@ -362,6 +362,25 @@ importers:
         specifier: ^5.7.0
         version: 5.9.3
 
+  packages/plugins/official/ai-chat-widget:
+    dependencies:
+      '@agentbase/plugin-sdk':
+        specifier: workspace:*
+        version: link:../..
+    devDependencies:
+      '@types/jest':
+        specifier: ^29.5.0
+        version: 29.5.14
+      jest:
+        specifier: ^29.7.0
+        version: 29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3))
+      ts-jest:
+        specifier: ^29.2.0
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
+      typescript:
+        specifier: ^5.7.0
+        version: 5.9.3
+
   packages/plugins/template:
     dependencies:
       '@agentbase/plugin-sdk':
@@ -376,7 +395,7 @@ importers:
         version: 29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3))
       ts-jest:
         specifier: ^29.2.0
-        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3)
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
       typescript:
         specifier: ^5.7.0
         version: 5.9.3
@@ -397,7 +416,7 @@ importers:
         version: 29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3))
       ts-jest:
         specifier: ^29.2.0
-        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3)
+        version: 29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3)
       typescript:
         specifier: ^5.3.0
         version: 5.9.3
@@ -11787,7 +11806,7 @@ snapshots:
 
   ts-interface-checker@0.1.13: {}
 
-  ts-jest@29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11))(typescript@5.9.3):
+  ts-jest@29.4.6(@babel/core@7.29.0)(@jest/transform@29.7.0)(@jest/types@30.3.0)(babel-jest@29.7.0(@babel/core@7.29.0))(jest-util@30.3.0)(jest@29.7.0(@types/node@22.19.11)(ts-node@10.9.2(@types/node@22.19.11)(typescript@5.9.3)))(typescript@5.9.3):
     dependencies:
       bs-logger: 0.2.6
       fast-json-stable-stringify: 2.1.0
diff --git a/tsconfig.json b/tsconfig.json
index 506c6fc..dd76fd3 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -19,5 +19,5 @@
       "@agentbase/shared/*": ["packages/shared/src/*"]
     }
   },
-  "exclude": ["node_modules", "dist"]
+  "exclude": ["node_modules", "dist", "packages/plugins"]
 }