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

# Attribution

> Attribute API calls to the end person they concern.

When a request concerns an end person, tell us who that person is. We use these
headers to attribute the action for compliance, and to correlate your identifiers
with ours in logs and support.

```bash theme={"theme":"catppuccin-mocha"}
curl https://api.engine.usesophic.com/me \
  -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
  -H "Person-Id: per_…" \
  -H "Client-User-Id: your-end-user-id"
```

Neither header replaces [authentication](/api-reference/auth). Your Bearer token
still identifies your tenant; these headers identify the end person the call is
about.

## Person-Id

Send `Person-Id` with our person ID (`per_…`) whenever the request concerns an
end person. This is how we attribute the call for compliance.

Create persons via [`POST /persons`](/api-reference/customers/create-a-person),
then pass the returned ID on subsequent requests that act for that person.

## Client-User-Id

`Client-User-Id` is your own identifier for the same end user. It's optional and
doesn't affect authorization. Send it when you want us to correlate our logs with
yours during support or incident investigation.

The format is up to you. Prefer a stable ID from your system rather than a
display name or email.

## Limits

Both headers are capped at 255 characters. Longer values return `400` with
`person_id_too_long` or `client_user_id_too_long`. See
[Errors](/api-reference/errors).

Don't put secrets or unnecessary PII in `Client-User-Id`. We store the value in
our request logs.