# Qwen publishes SAE residual stream weights for Qwen3.5-2B-Base (W32K, L0 50)

> Qwen released a sparse autoencoder (SAE) residual stream decomposition for the Qwen3.5-2B-Base model, configured with width 32K and L0 sparsity target 50. Part of the Qwen-Scope mechanistic interpretability research effort (arXiv:2605.11887). No capability or benchmark data is provided in the source.

| | |
|---|---|
| **Tool** | Qwen |
| **Version** | — |
| **Kind** | release |
| **Published** | 2026-04-27 |
| **Observed** | 2026-08-11 |
| **Significance** | 1/5 |
| **Breaking** | no |
| **Categories** | feature, model-support, capability |

> **Note:** this classification is below our confidence threshold and is pending human review.

## What changed


Model repository `Qwen/SAE-Res-Qwen3.5-2B-Base-W32K-L0_50` published on Hugging Face.

- Tags: `topk_sae`, `sparse-autoencoder`, `sae`, `mechanistic-interpretability`, `interpretability`, `qwen-scope`, `arxiv:2605.11887`
- Base model: `Qwen/Qwen3.5-2B-Base`
- License: other (not specified)


## Sources

- [hf_model](https://huggingface.co/Qwen/SAE-Res-Qwen3.5-2B-Base-W32K-L0_50) — retrieved 2026-08-11


## Community

_No curated reactions recorded. Facts and community takes are kept in separate layers
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Canonical: https://changelogs.info/qwen/qwen-publishes-sae-residual-stream-weights-for-qwen3-5-2b-base-w32k-l0-50
Entity: https://changelogs.info/qwen
Event ID: `evt_2026-04-27_qwen_qwen-sae-res-qwen3-5-2b-base-w32k-l0-50`
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