Chumsak: a local Gemma 4 grader for Korea's 2%-pass-rate engineering exam

Description and use

Chumsak is a local grader for Korea’s information‑management engineering exam that uses Gemma 4 to give instant rubric scores, missing keywords, fixes, and a model outline, all on the user’s machine.

Problem

Candidates for Korea’s 정보관리기술사 exam need timely, detailed feedback on handwritten practice essays, but existing prep providers offer feedback only once a week or month and at high cost.

Outcome

Chumsak provides instant, detailed grading of practice essays on a local machine, reducing cost and privacy risk while enabling frequent feedback for exam candidates.

Workflow

• 1. User pastes an answer or uploads a photo of a handwritten sheet.
• 2. The FastAPI backend receives the text and sends it to Ollama running Gemma 4.
• 3. Gemma 4 returns a JSON rubric score constrained by a Pydantic schema.
• 4. Python converts rubric scores into an estimated overall score and identifies missing keywords.
• 5. The app presents the score, suggested fixes, and a model outline to the user.
• 6. Score history is stored locally in the browser’s localStorage.

Evidence

In 2025, 1,824 people sat it and 41 passed (2.2%)

Source

Chumsak (첨삭, "marking up someone's writing") is that feedback loop, running on your own laptop.

Source

Paste an answer, or photograph a handwritten sheet, and an open-weight model: scores it on five weighted criteria the way graders think about these essays, turns that into an estimated score out of 25 (essay) or 10 (short answer) against the 60% pass line, lists the keywords a top answer would include, gives the three fixes that would raise the score most, and a model outline.

Source