README.md

metadata

title: Elffuss Code
emoji: 🧑‍💻
colorFrom: purple
colorTo: pink
sdk: static
app_file: index.html
pinned: false
license: apache-2.0
short_description: A VS Code-style IDE with a local AI agent, in-browser
tags:
  - webgpu
  - transformers.js
  - local-llm
  - agent
  - code
  - gemma

🧑‍💻 Elffuss Code — a VS Code-style IDE with an AI soul, 100% in your browser

Open a local folder and a full web IDE unfolds around it — real Monaco (the VS Code editor), a file tree, tabs — with an AI agent that reads, searches and edits your project for real. The model runs on your GPU via WebGPU. Your code never leaves your machine.

⚡ Build the best thing you can with Elffuss — 15-minute challenge, open until Sun 9 Aug 2026. Open one of your own folders and let the agent fix a real bug or add a small feature in 15 minutes, then post a screenshot of the diff (plus your prompt) as a reply on X or a comment on LinkedIn. Every like counts, wherever you post it — X, LinkedIn or the Community tab of this Space. We tally them all on Sunday; the most-liked entry wins and gets featured in this Space and in the repo.

⚠️ Open it full-screen (direct link) — the File System Access API (opening a local folder) is blocked inside the embedded iframe.

In the demo a small model running entirely in the browser reads calc.py, finds a real bug and fixes it with a minimal edit — genuine tool-calling, not autocomplete.

Why it's different

• Your code stays local. The folder is opened via the File System Access API — no upload, no account.
• The model runs on your GPU (WebGPU, Gemma-4 E4B via LiteRT-LM; ONNX/transformers.js + our healed LFM2.5-1.2B as fallback).
• Real tool-calling: code.tree, code.read, code.search, code.edit, code.write — you watch every call.
• Real editor: Monaco, file tree, tabs, Ctrl+S, and git branch/last commit parsed straight from .git.
• Zero install, zero build. Vanilla ES modules.
• Your language: the whole IDE follows your browser's language (English, Spanish and more).
• External providers (OpenAI, Anthropic, Ollama) are opt-in; keys stay in your browser.
• Optional local bridge for real node / npm / python execution — downloaded from the main site.

How it's built

Four write-ups on the full stack — model, runtime, agent harness, editor and filesystem access, all in one tab: https://bitacora.utopiaia.com/#elffuss

Links

• 🌐 Full app: https://elffuss-code.utopiaia.com
• 💻 Source (Apache-2.0): https://github.com/KikoCis/elffuss-code
• ✳️ Sibling project — Elffuss Claw (agentic OS): https://huggingface.co/spaces/KikoCis/elffuss-claw
• 🧬 Shared core: https://github.com/KikoCis/elffuss

Gestión de contexto — cómo se mide

El empaquetador de contexto no se elige por intuición. Números medidos a igual presupuesto de tokens:

Sesiones reales de agente (25 sesiones, 174 sondas, recuerdo de hechos, sin juez LLM):

	recuerdo
truncar por la cola	7,0 %
versión anterior	15,1 %
esta	65,3 % ± 8,5

Memoria a largo plazo (200 preguntas, F1 del propio repo del banco, modelo real respondiendo, ~8 % del contexto):

	F1
el contexto COMPLETO, sin comprimir	22,56
truncar por la cola	6,62
heurísticas escritas a mano	6,07
BM25 sin IDF	20,34
BM25	23,59
embeddings	23,95
fusión por rangos (BM25 + embeddings)	28,09

Recuperar bien bate a tenerlo todo: 28,09 frente a 22,56 usando el 8 % de los tokens. Lo irrelevante no es lastre neutro — distrae.

Otras dos cosas que se miden y no se suponen: activar las heurísticas costaba −3,02 F1, y quitar la IDF cuesta −3,25. Lo semántico no sustituye al léxico, le cubre el punto ciego: sin solape de vocabulario entre pregunta y respuesta los embeddings ganan (24,28 vs 18,60), con solape gana BM25 (29,33 vs 23,58), y la fusión se queda con los dos.

Referencias: BM25 (Robertson et al., TREC-3 1994) · IDF (Spärck Jones, 1972) · RRF (Cormack et al., SIGIR 2009) · MMR (Carbonell & Goldstein, SIGIR 1998) · sumideros de atención (Xiao et al., ICLR 2024) · tiempo de validez (Snodgrass & Ahn, SIGMOD 1985).

La historia completa, con lo que salió mal: https://bitacora.utopiaia.com/posts/16-beaten-by-doing-nothing.html