> ## Documentation Index
> Fetch the complete documentation index at: https://docs.foglamp.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration

> Every option accepted by foglamp().

`foglamp(config?)` accepts the options below. Every field is optional. The v4
to v6 entry point takes the same options: `wrap(ai, config)` accepts them all,
plus a `context` for defaults (see [wrap](/sdk/wrap)).

```ts theme={null}
const fog = foglamp({
  apiKey: process.env.FOGLAMP_API_KEY,
  endpoint: process.env.FOGLAMP_INGEST_URL,
  flushIntervalMs: 5000,
  maxBatchTraces: 50,
  maxBatchSpans: 500,
  maxPayloadChars: 100_000,
  recordInputs: true,
  recordOutputs: true,
  debug: false,
  onError: (err) => console.error(err),
});
```

## Options

| Option            | Type     | Default                             | Description                                                                                                                                                                                                                                          |
| ----------------- | -------- | ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `apiKey`          | string   | `FOGLAMP_API_KEY`                   | Your `fl_...` key. If unset, the collector is off.                                                                                                                                                                                                   |
| `endpoint`        | string   | `https://ingest.foglamp.dev/ingest` | Where to send data. Set this when self-hosting.                                                                                                                                                                                                      |
| `flushIntervalMs` | number   | `5000`                              | How often batches are sent on long-running servers.                                                                                                                                                                                                  |
| `maxBatchTraces`  | number   | `50`                                | Send early once this many traces are buffered.                                                                                                                                                                                                       |
| `maxBatchSpans`   | number   | `500`                               | Send early once this many spans are buffered.                                                                                                                                                                                                        |
| `maxQueuedSpans`  | number   | `5000`                              | Max spans held in memory (for example when ingest is unreachable). Past it, the oldest traces are dropped and `onError` fires.                                                                                                                       |
| `maxTraceAgeMs`   | number   | `600_000`                           | A trace still open after this long (10 minutes) is closed as `abandoned` and counted as an error, so a crashed generation can't leak spans. A cleanly cancelled stream is handled right away instead, via the [`aborted` status](/dashboard/traces). |
| `maxPayloadChars` | number   | `100_000`                           | Max length for each `input`/`output` field. Longer values are cut off.                                                                                                                                                                               |
| `recordInputs`    | boolean  | `true`                              | Capture prompt text.                                                                                                                                                                                                                                 |
| `recordOutputs`   | boolean  | `true`                              | Capture response text.                                                                                                                                                                                                                               |
| `waitUntil`       | function | none                                | Serverless flush hook. Detected automatically on Vercel and Lambda; pass `ctx.waitUntil` on Cloudflare Workers. See [Runtimes](/sdk/runtimes).                                                                                                       |
| `fetch`           | function | global `fetch`                      | Custom fetch implementation.                                                                                                                                                                                                                         |
| `debug`           | boolean  | `false`                             | Log batching and flush activity.                                                                                                                                                                                                                     |
| `onError`         | function | none                                | Called on transport or serialization errors instead of throwing.                                                                                                                                                                                     |

<Warning>
  The ingest API caps any single `input` or `output` field at 1,000,000
  characters. `maxPayloadChars` (default 100,000) cuts off earlier to keep
  payloads small. Raise it only if you need fuller logs. Values above 1,000,000
  are clamped to that cap.
</Warning>

## Privacy: keeping text out

To record traces, cost, and timing without ever sending prompt or response
text, turn capture off:

```ts theme={null}
const fog = foglamp({
  recordInputs: false,
  recordOutputs: false,
});
```

Token counts and cost still work. They come from the provider's usage report,
not from the text.

## Error handling

The collector never throws into your app. Failures go to `onError` if you
provide one, and are otherwise ignored. Turn on `debug` to watch batching and
flushing during development.

```ts theme={null}
const fog = foglamp({
  debug: process.env.NODE_ENV !== "production",
  onError: (err) => reportToSentry(err),
});
```