AgentKit

Vercel AI SDK Memory, RAG & Chat History with Redis

Add long-term memory, RAG, and chat history to the Vercel AI SDK with Upstash Redis — drop-in tools for generateText and streamText, no separate vector database.

Upstash AgentKit builds AI agents on Upstash Redis: memory, conversation history, caching, and RAG, with no separate vector database. The semantic features run on Upstash Redis Search and its $smart fuzzy operator.

@upstash/agentkit-ai-sdk is the Vercel AI SDK adapter — drop-ins for generateText / streamText. redis defaults to Redis.fromEnv(), so you import only from this package.

ImportFeature
createChatHistoryDurable chat history on Redis Search — save, list, and $smart-search a user's transcripts.
createMemoryToolsrecall_memory + save_memory tools so the model reads and writes long-term memory.
createSearchToolssearch / aggregate / count tools over a Redis Search index (this is how you do RAG).
createRateLimitA configured Upstash Ratelimit to call before the model.
cachedToolsMemoize a map of AI SDK tools' results in Redis.
npm install @upstash/agentkit-ai-sdk @upstash/redis ai

AgentKit reads UPSTASH_REDIS_REST_URL / UPSTASH_REDIS_REST_TOKEN from the environment by default. Pass your own @upstash/redis client as redis to any helper to override.

How to store chat history with the AI SDK

A Redis-backed ChatHistory<UIMessage>, the durable source of truth for your conversations. userId comes from your auth session; chatId is the useChat id that the client posts. Save the full transcript from your route's onFinish:

// app/api/chat/route.tsimport { convertToModelMessages, createUIMessageStreamResponse, streamText, toUIMessageStream } from "ai";import { createChatHistory } from "@upstash/agentkit-ai-sdk";const history = createChatHistory();export async function POST(req: Request) {  const userId = await getSessionUserId(req); // your auth session, never a client-sent id  const { id: chatId, messages } = await req.json(); // useChat posts its chat id + the full transcript  const result = streamText({ model, messages: convertToModelMessages(messages) });  return createUIMessageStreamResponse({    stream: toUIMessageStream({      stream: result.stream,      originalMessages: messages,      onFinish: ({ messages }) =>        history.saveChat({ userId, sessionId: chatId, messages, title: "New chat" }),    }),  });}

To load a chat, take chatId from the page route and userId from the session, then seed useChat:

const chat = await history.getChat({ userId, sessionId: chatId }); // full transcript, or nullconst chats = await history.listChats({ userId, limit: 50 }); // summaries, no messagesconst hits = await history.searchChats({ userId, query: "headphones", target: "both", limit: 20 });// client: useChat({ id: chatId, messages: chat?.messages ?? [] })
Config and how it's stored
createChatHistory({  redis, // optional: defaults to Redis.fromEnv()  prefix: "agentkit:chat", // optional: base key prefix  indexName: "agentkit_chat", // optional: index name (defaults to the prefix)  ttlSeconds: 60 * 60 * 24 * 30, // optional: per-chat TTL (default: no expiry)});

Each chat is one JSON doc at agentkit:chat:<userId>:<sessionId> (keyed per user, so two users can't collide on a sessionId), indexed over userId + sessionId (filters) and userMessages + modelMessages ($smart fuzzy text); the raw messages array rides along unindexed. saveChat overwrites the whole array (no delta merge) — useChat sends the full conversation. Other methods: getChat / deleteChat ({ userId, sessionId }), listChats / searchChats ({ userId }).

Security — userId is the tenant boundary

Every method takes a single object; userId is required, non-empty, and may not contain :. Derive it from a verified server-side auth source — the subject/user id from your auth provider (Clerk, Auth.js/NextAuth, Supabase Auth, Auth0, …) — and never from a client-supplied header, query param, or body (read it from the session in your route). A chat can't be read or overwritten under a different userId.

How to add agent memory with the AI SDK

recall_memory and save_memory tools so the model reads and writes its own long-term memory.

import { createMemoryTools } from "@upstash/agentkit-ai-sdk";import { generateText, stepCountIs } from "ai";const tools = createMemoryTools({ userId });await generateText({ model, tools, stopWhen: stepCountIs(5), prompt: "What do you know about me?" });
Options and the userId tenant boundary
  • userId (required) — a string, or (input, options) => string.
  • redis — defaults to Redis.fromEnv().
  • topK — max memories recall returns.
  • minScore — BM25 relevance floor.
  • recallToolName / saveToolName — override the tool names.

userId is the only tenant boundary (required, non-empty, no :). Derive it from a verified server-side auth source (Clerk, Auth.js/NextAuth, Supabase Auth, Auth0, …) — never a client-supplied value. Memories are stored at agentkit:memory:<userId>:<id>.

How to add RAG with the AI SDK

search / aggregate / count tools over an Upstash Redis Search index; the model-facing descriptions are generated from your schema.

import { s } from "@upstash/redis";import { createSearchTools } from "@upstash/agentkit-ai-sdk";import { generateText, stepCountIs } from "ai";const schema = s.object({ name: s.string(), age: s.number(), city: s.string().noTokenize() });const tools = createSearchTools({ schema, indexName: "users" });await generateText({ model, tools, stopWhen: stepCountIs(5), prompt: "How many users named Ada live in London?" });
Options
  • schema (required) — built with s from @upstash/redis.
  • redis — defaults to Redis.fromEnv().
  • indexName — defaults to "agentkit:search".
  • prefix — key prefix for indexed JSON docs (defaults to "<indexName>:").
  • defaultLimit — default page size for search (10).

The index is created (and waitIndexing-ed) reactively on first use — no setup step.

How to add rate limiting with the AI SDK

A configured Upstash Ratelimit. Call .limit(identifier) before the model and short-circuit when over the limit.

import { createRateLimit, Ratelimit } from "@upstash/agentkit-ai-sdk";const ratelimit = createRateLimit({ limiter: Ratelimit.slidingWindow(20, "1 m") });const { success } = await ratelimit.limit(userId);if (!success) throw new Error("rate limited"); // or return a 429 from your route
Options
  • limiter (required) — e.g. Ratelimit.slidingWindow(20, "1 m") or fixedWindow(...).
  • redis — defaults to Redis.fromEnv().
  • prefix — base key prefix; keys are <prefix>:<identifier> (default agentkit:rateLimit).

There's no model wrapper. Pass a per-user identifier to .limit() to throttle per user.

How to cache tools with the AI SDK

Memoize a map of AI SDK tools' results in Redis. Each tool is cached under its map key, scoped to userId.

import { z } from "zod";import { generateText, tool } from "ai";import { cachedTools } from "@upstash/agentkit-ai-sdk";const tools = cachedTools(  {    getWeather: tool({      description: "Get the weather for a city",      inputSchema: z.object({ city: z.string() }),      execute: async ({ city }) => fetchWeather(city),    }),  },  { userId },);await generateText({ model, tools, prompt: "What's the weather in Paris?" });
Options

Pass tools built with the AI SDK's tool() (so each keeps full input/output inference). Second arg:

  • userId (required) — a string, or (input, options) => string; scopes every entry to this user.
  • redis — defaults to Redis.fromEnv().
  • ttlSeconds — default per-result TTL for every tool.

Cache keys are agentkit:toolCache:<userId>:<toolName>:<hash-of-input> — the toolName is the map key, so you never pass a name yourself.

How to put it all together with the AI SDK

A single streamText route can wire every feature: rate limit first, then memory, search, and cached tools, persisting the whole conversation in onFinish:

// app/api/chat/route.tsimport { openai } from "@ai-sdk/openai";import {  convertToModelMessages,  createUIMessageStreamResponse,  streamText,  stepCountIs,  toUIMessageStream,  tool,  type UIMessage,} from "ai";import { z } from "zod";import { s, Redis } from "@upstash/redis";import {  Ratelimit,  cachedTools,  createChatHistory,  createMemoryTools,  createRateLimit,  createSearchTools,} from "@upstash/agentkit-ai-sdk";export async function POST(req: Request) {  const { id, messages } = (await req.json()) as { id: string; messages: UIMessage[] };  const redis = Redis.fromEnv();  // Derive this from your verified auth session in production (Clerk, Auth.js, …), never a client value.  const userId = "user-123";  // 1. Rate limit (by user) before any model work.  const ratelimit = createRateLimit({ redis, limiter: Ratelimit.slidingWindow(30, "1 m") });  const { success } = await ratelimit.limit(userId);  if (!success) return new Response("Rate limited", { status: 429 });  // 2. Memory, search, and cached tools — all scoped to this user.  const tools = {    ...createMemoryTools({ redis, userId }),    ...createSearchTools({ schema: s.object({ title: s.string(), author: s.string() }), redis, indexName: "books" }),    ...cachedTools(      {        convert_price: tool({          description: "Convert a USD price to another currency.",          inputSchema: z.object({ usd: z.number(), currency: z.string() }),          execute: async ({ usd, currency }) => ({ currency, amount: usd * 0.92 }),        }),      },      { userId, redis },    ),  };  const result = streamText({    model: openai("gpt-5.4-mini"),    messages: await convertToModelMessages(messages),    tools,    stopWhen: stepCountIs(5),  });  // 3. Persist the whole conversation when the stream finishes.  const history = createChatHistory({ redis });  return createUIMessageStreamResponse({    stream: toUIMessageStream({      stream: result.stream,      originalMessages: messages,      onFinish: ({ messages }) => history.saveChat({ userId, sessionId: id, messages, title: "New chat" }),    }),  });}

A complete, runnable Next.js demo (useChat UI, chat sidebar with fuzzy search, inline tool calls) lives in examples/ai-sdk-demo.

Loading search…