# Amp — Opus 5.5

- Company: Amp (ampcode.com)
- Announced: 2026-09-28
- Category: model-update
- Coverage: not counted
- Announcement: yes
- Group: models
- Source: https://ampcode.com/news/opus-5.5
- Record: https://forck.live/items/14910-opus-5-5
- Subject: Amp
- Models affected: Claude Opus 5.5, GPT-5.6 Sol, Opus 5, Fable 5.1, GPT-6 Sol, GPT-6 Astra

Amp replaced GPT-5.6 Sol with Claude Opus 5.5 as the default model for its medium mode. In internal evaluations, Opus 5.5 solved 65% of tasks (up from GPT-5.6 Sol's 61% and Opus 5's 56%) at 10% lower cost than GPT-5.6 Sol and 25% lower than Opus 5. The model is set to high reasoning effort by default, as higher settings degrade performance and increase cost.

## Evidence

Verbatim from https://ampcode.com/news/opus-5.5:

> In our internal evals, Opus 5.5 solved 65% of tasks, up from GPT-5.6 Sol's 61% and Opus 5's 56% . And it did that for 10% less than GPT-5.6 Sol and 25% less than Opus 5.

## Follow-ups

- 新智元 (reported, 28 Sep): 刚刚，Gemini 4 Pro全新曝光，实测碾压Opus 5.5！ — https://forck.live/items/14454-gemini-4-pro-opus-5-5
- 新智元 (reported, 28 Sep): 震撼，Opus 5.5首次颠覆Dijkstra算法最短路径！ — https://forck.live/items/14455-opus-5-5-dijkstra

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