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

# Release notes

> Perceptron Mk1.5 API integration changes.

## 2026-09-25 — Perceptron Mk1.5

Use the model ID `perceptron-mk1.5` with the chat completions API.

* **Audio input:** transcribe, summarize, and ask questions using `input_audio`, `audio_url`, or `audio_file_id` with WAV, MP3, or FLAC. The current per-item limit is 16,384 audio tokens, approximately 21.8 minutes; audio also occupies the shared 36,864-token context. Usage is reported in `usage.prompt_tokens_details.audio_tokens`. See [Audio](/perceptron-mk1.5/capabilities/audio).
* **Video soundtracks:** set `vision_config.enable_audio_in_video: true` to analyze audio alongside video frames. This is off by default. See [video soundtracks](/perceptron-mk1.5/capabilities/video-understanding#analyze-video-soundtracks).
* **Reasoning effort:** use `none`, `minimal`, `low`, `medium`, or `high` on chat completions and Multilook. `vision_config.enable_thinking` is deprecated. See [Reasoning](/perceptron-mk1.5/capabilities/thinking).
* **Function calling:** declare functions, receive tool calls, and return results for the next turn. See [tool calling](/perceptron-mk1.5/capabilities/tool-calling).
* **Video tracking:** request `<track>` output with timestamped spatial observations. See [video tracking](/perceptron-mk1.5/capabilities/video-tracking).
* **Multiple assets:** the optional `asset_idx` attribute associates annotations with an input across images, videos, and conversation history. See [multiple assets](/perceptron-mk1.5/guides/multiple-assets) for handling both present and omitted selectors.
* **Structured output guidance:** distinguish native annotations, constrained final responses, and function arguments. See [structured outputs](/perceptron-mk1.5/capabilities/structured-outputs).
* **Hosted MCP:** `question` and `caption` accept `modality: "audio"` and opt-in video soundtracks; all four inference tools accept `reasoning_effort`.
* **MCP model default:** `question`, `caption`, `ocr`, and `detect` now default to `perceptron-mk1.5` when `model` is omitted. Pass `model: "perceptron-mk1"` to retain the previous model. See the [MCP guide](/perceptron-mk1.5/guides/mcp) for hosted access and npm bridge compatibility.

The [model card](/perceptron-mk1.5/models/perceptron-mk1.5) lists supported inputs, context limits, and pricing.