{messages.map((message) => (
);
}
```
## Tool calling [#tool-calling]
Define tools with `toolDefinition` and attach a server handler — TanStack AI runs the tool loop for you:
```typescript
import { chat, toServerSentEventsResponse, toolDefinition } from "@tanstack/ai";
import { llmGatewayText } from "@tanstack/ai-llmgateway";
import { z } from "zod";
const getWeather = toolDefinition({
name: "get_weather",
description: "Get the current weather for a location",
inputSchema: z.object({
location: z.string(),
}),
}).server(async ({ location }) => {
return { temperature: 72, condition: "sunny" };
});
export async function POST(request: Request) {
const { messages } = await request.json();
const stream = chat({
adapter: llmGatewayText("gpt-5.6-terra"),
messages,
tools: [getWeather],
});
return toServerSentEventsResponse(stream);
}
```
## Reasoning models [#reasoning-models]
Reasoning models stream their thinking as `reasoning_content` deltas, which the adapter surfaces as AG-UI `REASONING_*` events — they arrive in `useChat` as `thinking` parts. Control the depth with `reasoning_effort` in `modelOptions`:
```typescript
const stream = chat({
adapter: llmGatewayText("kimi-k3"),
messages,
modelOptions: {
temperature: 0.7,
reasoning_effort: "high",
},
});
```
`reasoning_effort` accepts the extended scale `none` / `minimal` / `low` / `medium` / `high` / `xhigh` / `max`; which tiers a model honors depends on the model and the provider it routes to. Parameters a routed provider doesn't support are stripped server-side, so `modelOptions` stay portable across models. See [reasoning support](https://docs.llmgateway.io/features/reasoning).
## Summarization [#summarization]
The adapter also covers TanStack AI's `summarize` surface:
```typescript
import { summarize } from "@tanstack/ai";
import { llmGatewaySummarize } from "@tanstack/ai-llmgateway";
const result = await summarize({
adapter: llmGatewaySummarize("gpt-5.4-mini"),
text: "Long article text...",
stream: false,
});
```
## Self-hosted deployments [#self-hosted-deployments]
`createLLMGatewayText` takes the key explicitly plus a `baseURL` for self-hosted gateways:
```typescript
import { createLLMGatewayText } from "@tanstack/ai-llmgateway";
const adapter = createLLMGatewayText(
"gpt-5.6-terra",
process.env.LLM_GATEWAY_API_KEY!,
{
baseURL: "https://gateway.internal.example.com/v1",
},
);
```
{message.role === "assistant" ? "Assistant" : "You"}
{message.parts.map((part, index) =>
part.type === "text" ?
))}
{part.content}
: null, )}How can I help you?
{textContent ? {textContent} : null}
{imageParts.length > 0 ? (
);
} else {
return (
{imageParts.map((part, idx: number) => {
const { base64Only, mediaType } =
parseImagePartToDataUrl(part);
if (!base64Only) {
return null;
}
return (
) : null}
{isLastMessage &&
(status === "submitted" || status === "streaming") && (
{p.text}
;
}
return null;
})}
{status === "streaming" ? (
stop()} variant="ghost">
Stop
) : null}