---
title: "Replace a Model Fusion configuration"
method: PUT
path: "/v3/model-fusions/{model_fusion_id}"
tags: ["Model Fusions"]
---

# Replace a Model Fusion configuration

`PUT /v3/model-fusions/{model_fusion_id}`

Replaces the complete Fusion configuration. The key is immutable.

## Path parameters

- `model_fusion_id` string, required

## Request body

- UpdateModelFusionRequest
  - `panel_models` string[], required
  - `judge_model` string, required
  - `synthesis_mode` 'MODEL_FUSION_SYNTHESIS_MODE_UNSPECIFIED' | 'MODEL_FUSION_SYNTHESIS_MODE_ANALYSIS' | 'MODEL_FUSION_SYNTHESIS_MODE_JUDGE_WRITES_FINAL', required
  - `preset` 'MODEL_FUSION_PRESET_UNSPECIFIED' | 'MODEL_FUSION_PRESET_GENERAL' | 'MODEL_FUSION_PRESET_QUALITY' | 'MODEL_FUSION_PRESET_BUDGET' | 'MODEL_FUSION_PRESET_CODE' | 'MODEL_FUSION_PRESET_SAFETY', required
  - `orchestrator_model` string — Required for analysis mode and omitted for judge_writes_final mode.
  - `web_tools` boolean, required
  - `max_tool_calls` integer, required — Required. Must be between 0 and 20. Zero disables Fusion-managed tool calls.
  - `feed_raw_to_synth` boolean, required

## Response `200`

OK

- UpdateModelFusionResponse
  - `model_fusion` ModelFusion, required
    - `model_fusion_id` string, required — Unique Model Fusion identifier assigned by ORQ.
    - `key` string, required — Stable lowercase key used in the gateway model reference.
    - `model_ref` string, required — Workspace-qualified gateway model reference.
    - `panel_models` string[], required — Distinct model references evaluated independently.
    - `judge_model` string, required — Model reference used to judge anonymized panel answers.
    - `synthesis_mode` 'MODEL_FUSION_SYNTHESIS_MODE_UNSPECIFIED' | 'MODEL_FUSION_SYNTHESIS_MODE_ANALYSIS' | 'MODEL_FUSION_SYNTHESIS_MODE_JUDGE_WRITES_FINAL', required
    - `preset` 'MODEL_FUSION_PRESET_UNSPECIFIED' | 'MODEL_FUSION_PRESET_GENERAL' | 'MODEL_FUSION_PRESET_QUALITY' | 'MODEL_FUSION_PRESET_BUDGET' | 'MODEL_FUSION_PRESET_CODE' | 'MODEL_FUSION_PRESET_SAFETY', required
    - `orchestrator_model` string — Required only for analysis mode; omitted when the judge writes the final answer.
    - `web_tools` boolean, required — Whether the Fusion-managed ORQ web tools are available to panel and judge phases.
    - `max_tool_calls` integer, required — Maximum Fusion-managed web tool calls per participating phase. Zero disables Fusion-managed tool calls.
    - `feed_raw_to_synth` boolean, required — Whether raw panel candidate answers are included in synthesis input.
    - `enabled` boolean, required — Whether the Fusion is available to gateway requests.
    - `created_at` string, date-time, required
    - `updated_at` string, date-time, required

## Changes

> 350 revisions in range; 136 not diffed.

- **2026-09-28** `3c7d859558ee` — 1 info
  - endpoint added

[Change history](https://skmtc.dev/orq-ai/apis/orq-ai-api/changes/v3/model-fusions/:model_fusion_id/put.md)

---

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