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

# October 2026

> Changes shipped in October 2026.

### October 19, 2026

**\[Improved + API]** A reused `Idempotency-Key` names the resource it created, and a replay says it is one

A `422 IDEMPOTENCY_KEY_REUSED` now carries `params.resource_type` (`document_packet` or `eval`) and `params.resource_id`, the id the first request's response gave, so a caller can read the original resource instead of sending a new key and paying for a second run or eval. `params` is absent when the first request named no single resource, as when an upload's files changed. A replayed `2xx` carries the `Idempotent-Replayed: true` header, and a first response does not. Both are additive. The `detail` now says what to do: resend the identical request, or use a new key only for a genuinely new request. See [Idempotency](/api-reference-v3/introduction#idempotency).

### October 16, 2026

**\[New + API]** Read and set one dataset document's ground truth

`GET /v3/document-packets/{document_packet_id}/ground-truth/` reads a dataset document's ground truth, keyed by field `persistent_id` (`null` until it is first set), and `PUT` on the same path creates or replaces it: `201` on the first write, `200` on a replace, both with the stored document. Both take an optional workflow version and extract node, and answer with the `version_id` and `node_id` they used. A production packet answers `409 NOT_IN_DATASET`, now a documented error code. The Python SDK adds `get_ground_truth` and `set_ground_truth`, the TypeScript SDK `getGroundTruth` and `setGroundTruth`, and the MCP server the `get_ground_truth` and `set_ground_truth` tools. See [Get ground truth](/api-reference-v3/datasets/get-ground-truth) and [Set ground truth](/api-reference-v3/datasets/set-ground-truth).


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