ai-core/middleware SKILL.md skillA
ai-core/middleware from tanstack/ai is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add tanstack/ai/ai-core/middleware@git:20261022.f1b3f65Pins git:20261022.f1b3f65 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- tanstack/ai
- Path
packages/ai/skills/ai-core/middleware/SKILL.md- Versions recorded
- 8
- Latest version
- git:20261022.f1b3f65, committed Oct 22, 2026
- First version recorded
- Jul 27, 2026
- Size
- 39,457 bytes
- Repository stars
- 3,337
- License
- MIT
Chat lifecycle middleware hooks: onConfig, onStart, onChunk, onBeforeToolCall, onAfterToolCall, onUsage, onFinish, onAbort, onError. Use for analytics, event firing, tool caching (toolCacheMiddleware), logging, and tracing. Middleware array in chat() config, left-to-right execution order. NOT onEnd/onFinish callbacks on chat() — use middleware.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Middleware
> **Dependency note:** This skill builds on ai-core. Read it first for critical rules.
## Setup — Analytics Tracking Middleware
```typescript
import { chat, toServerSentEventsResponse } from '@tanstack/ai'
import { openaiText } from '@tanstack/ai-openai'
import { trackAnalytics, reportError } from './analytics'
export async function POST(request: Request) {
const { messages, threadId } = await request.json()
const stream = chat({
adapter: openaiText('gpt-5.5'),
messages,
threadId,
middleware: [
{
onStart: (ctx) => {
console.log('Chat started:', ctx.model)
},
onFinish: (ctx, info) => {
trackAnalytics({ model: ctx.model, tokens: info.usage?.totalTokens })
},
onError: (ctx, info) => {
reportError(info.error)
},
},
],
})
return toServerSentEventsResponse(stream)
}
```
## Hooks Reference
Every hook receives a `ChatMiddlewareContext` as its first argument, which provides
`requestId`, `streamId`, `phase`, `iteration`, `chunkIndex`, `callMetadata`, `model`, `provider`,
…Read the whole file at its exact version.
How to install
mdr add tanstack/ai/ai-core/middleware@sha256:2579c6f26dd5f454The line at the top of this page pins the label git:20261022.f1b3f65, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_5q3e5ls5y7nubgnv)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 8 versions of this file, between Jul 27, 2026 and Oct 22, 2026, about one every 12 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20261022.f1b3f65 latest | 2026-10-22 | f1b3f65 | 39,457 B | A | view · diff |
| git:20261022.7a0a48b | 2026-10-22 | 7a0a48b | 39,337 B | A | view · diff |
| git:20260924.9ab4f76 | 2026-09-24 | 9ab4f76 | 39,321 B | A | view · diff |
| git:20260909.53e2ec0 | 2026-09-09 | 53e2ec0 | 38,948 B | A | view · diff |
| git:20260820.47699ed | 2026-08-20 | 47699ed | 35,909 B | A | view · diff |
| git:20260804.d9d1e1f | 2026-08-04 | d9d1e1f | 35,636 B | A | view · diff |
| git:20260728.478a4da | 2026-07-28 | 478a4da | 30,758 B | A | view · diff |
| git:20260727.4ab149f | 2026-07-27 | 4ab149f | 29,466 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (39457 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
tanstack/ai · 3,337 stars · license MIT · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_5q3e5ls5y7nubgnv GET https://markdownregistry.com/api/v1/resolve?ref=tanstack/ai/ai-core/middleware GET https://markdownregistry.com/api/v1/blob/2579c6f26dd5f4542e1870a6a6e6b7d66cd99ae5e818e7c884477fdc9ff1e3d1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.