---
title: "Apply Model Family Handler"
method: POST
path: "/api/settings/apply-model-family"
tags: ["runtime_mutations", "settings"]
---

# Apply Model Family Handler

`POST /api/settings/apply-model-family`

Apply a model family by fanning it out into the per-role model settings.

Persists concrete flagship values for the agent roles, so each role holds a
concrete model after onboarding. The family itself is not persisted — it is
only a transient way to propagate these per-role defaults. Users can still
change any role afterward.

## Request body

- ApplyModelFamilyRequest
  - `family` string, required

## Response `200`

Successful Response

- unknown

## Other responses

- `422` — Validation Error

## Changes

- **2026-09-18** `abf76937a751` — 2 info
  - added the optional property `detail/items/ctx` to the response with the `422` status
  - added the optional property `detail/items/input` to the response with the `422` status

[Change history](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/changes/api/settings/apply-model-family/post.md)

---

[API](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api.md) · [All operations](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/llms.txt) · [OpenAPI document](https://skmtc.dev/quadrillion/apis/quadrillion-cloud-api/revisions/d7f2f3b8e82d?raw)