tanstack-ai-memory · diff
git:20260723.347b61b to git:20260724.cc88874
14 added, 9 removed. Audit A to A.
---
name: tanstack-ai-memory
description: Use when wiring memoryMiddleware from @tanstack/ai-memory into a chat() call — covers the recall/save adapter contract, scope shape and server-side scope security, the recall-inject / deferred-save lifecycle, choosing an adapter (inMemory, redis, hindsight, mem0, honcho), and devtools events.
---
# TanStack AI Memory Middleware
Use this when adding **server-side memory** to a `chat()` call. Everything lives in
`@tanstack/ai-memory`. A memory adapter is a single contract with two verbs — `recall`
and `save` — and the middleware is thin: it recalls into the system prompt before the
model runs and defers `save` after the turn finishes.
## When to reach for it
- A user expects "remember what I told you last time."
- Per-user or per-thread context that must survive across sessions.
- A hosted memory service (mem0, Honcho, Hindsight).
Do NOT use this just to keep recent messages — that's the `messages` array on `chat()`.
Memory is for cross-turn / cross-session recall, not within-turn history.
## Wire it up
```ts
import { chat } from '@tanstack/ai'
import { openaiText } from '@tanstack/ai-openai'
import { memoryMiddleware } from '@tanstack/ai-memory'
import { inMemory } from '@tanstack/ai-memory/in-memory'
const memory = inMemory() // dev/tests only — see the in-memory skill
const stream = chat({
adapter: openaiText('gpt-5.5'),
messages,
context: { session }, // attached by your auth middleware
middleware: [
memoryMiddleware({
adapter: memory,
// Derive scope server-side from trusted session state.
scope: (ctx) => {
const session = getSession(ctx)
- return { sessionId: session.threadId, userId: session.userId }
+ return { threadId: session.threadId, userId: session.userId }
},
}),
],
})
```
`memoryMiddleware` options: `adapter`, `scope` (static or a function of `ctx`),
`role` (`'recall+save'` default, or `'save-only'`), and `onRecall` / `onSave` telemetry
callbacks.
## The contract
```ts
interface MemoryAdapter {
id: string
recall(scope, query): Promise<RecallResult> // { systemPrompt, fragments?, tools?, toolGuidance? }
save(scope, turn): Promise<Array<SaveReceipt>> // turn = { user, assistant }; extraction lives HERE
inspect?(scope): Promise<MemorySnapshot> // optional (devtools)
listFacts?(scope): Promise<Array<MemoryFact>> // optional (devtools)
}
```
- `recall` decides relevance and renders a `systemPrompt`; it may also return `tools` +
`toolGuidance` to hand the model direct control of memory (hindsight does this).
- `save` owns extraction — turning the raw turn into whatever gets persisted.
## Scope security
- `MemoryScope` is `{ sessionId, userId? }` and is the isolation boundary. **Never trust a
- client-supplied `userId`/`sessionId`.** Resolve scope server-side from session/auth and
- pass the validated session through `chat({ context: { session } })`. If you accept a
- thread id from the request body, validate it belongs to the session user BEFORE using it.
+ `MemoryScope` is an alias of the shared `Scope` type from `@tanstack/ai`:
+ `{ threadId, userId?, tenantId?, namespace? }`. It is the isolation boundary. **Never
+ trust a client-supplied `userId`/`threadId`.** Resolve scope server-side from
+ session/auth and pass the validated session through `chat({ context: { session } })`. If
+ you accept a thread id from the request body, validate it belongs to the session user
+ BEFORE using it.
## Adapters
- - `inMemory()` from `@tanstack/ai-memory/in-memory` — dev, tests, single-process demos.
- - `redis({ redis })` from `@tanstack/ai-memory/redis` — production, plain Redis.
- - `hindsight()` / `mem0()` / `honcho()` — hosted memory services (optional peer SDKs).
+ - `inMemory()` / `redis()` — exact match on `threadId` + optional `userId`/`tenantId`
+ (`namespace` ignored). Redis index keys include all three segments.
+ - `hindsight()` — bank `{tenant|_}__{user}__{threadId}`.
+ - `mem0()` — `user_id` + `run_id` (`threadId`); no `tenantId`.
+ - `honcho()` — session `{tenant|_}__{threadId}`; peer tenant-prefixed when set.
- Custom — implement `recall`/`save` and run `@tanstack/ai-memory/tests/contract`.
## Failure modes
Memory failures are non-fatal: a throwing `recall` or `save` emits `memory:error` and
the run continues with degraded memory. Streaming is never blocked; a failed save never
fails the turn.
## Devtools
Five events on `aiEventClient` (from `@tanstack/ai-event-client`):
`memory:retrieve:started` / `:completed`, `memory:persist:started` / `:completed`,
`memory:error` (`phase: 'recall' | 'save'`). Payloads carry the adapter id and
- fragment/receipt counts, not full memory text.
+ fragment/receipt counts, not full memory text. Error events include `scope` only
+ when it was already resolved; if the resolver threw, `scope` is omitted.