---
license: mit
tags: [preserved, repository-exploration, subagent, coder, agentic, qwen3, 256k, long-context]
language: [en]
pipeline_tag: text-generation
---

# FastContext-1.0-4B-SFT (preserved original weights)

**Preserved copy of Microsoft's FastContext-1.0-4B-SFT**, which Microsoft **deleted from both HuggingFace and GitHub** (verified: 404 on both) about two weeks after open-sourcing it under MIT. Re-uploaded here so the weights stay available. **Own your AI.**

## What it is
A **repository-exploration subagent** for coding agents: invoked on-demand by your main agent, it fires **parallel read-only tool calls (READ / GLOB / GREP)** across a repo and returns **only the file paths + line ranges you need** as focused context — offloading file discovery so your coding agent burns far fewer tokens. Microsoft's announcement reported **~60% fewer tokens** and **+5.5% SWE-bench** *(their figures; source now deleted)*.

Architecture: plain **Qwen3 dense 4B** (`Qwen3ForCausalLM`, 36 layers, **256K context**, MIT).

## Quantized GGUF
Long-context-imatrix GGUFs (any llama.cpp backend): **KikoCis/FastContext-1.0-4B-longctx-imatrix-GGUF**.

## Credit
Original © Microsoft, MIT license. This is an unmodified preservation mirror (weights unchanged).