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I tried to fire my LLM API. Open models passed one task and failed the other.

This is a submission for the Hacktoberfest Open-Source AI Challenge Week 2: Side Hustle What I Built Open-Switch answers one question: can an open model replace your closed LLM API on YOUR data? It runs your

I tried to fire my LLM API. Open models passed one task and failed the other.

This is a submission for the Hacktoberfest Open-Source AI Challenge Week 2: Side Hustle

What I Built

Open-Switch answers one question: can an open model replace your closed LLM API on YOUR data?

It runs your workflow through open-weight models, scores them with bootstrap 95% CIs, and gives a verdict: Safe Switch or No Safe Switch. It also tells you if a LoRA fine-tune pays for itself.

Who pays: B2B SaaS teams cutting LLM bills, and consultants selling migration audits. Hypothesis: $49/mo self-serve, $199/mo agency.

Demo

Runs fully local (no hosted link, by design: your data never leaves your machine):

git clone https://github.com/SynthReaper/ghw-hacktoberfest26.git
cd ghw-hacktoberfest26/switchable && pip install -e .
openswitch run --models gemma-2b-local,gemma-9b-local --task specs/task.yaml

Code

MLH x Hacktoberfest Challenge Projects (2026)

Workspace containing hackathon projects for DEV Hacktoberfest Challenges.

Projects

  • paper-trail/: Paper Trail — Offline Local Walk Generator & Analog Field Card (DEV Hacktoberfest Open-Source AI Challenge Week 1: Touch Grass).
  • switchable/: Open-Switch — Autonomous evaluation and migration engine to verify whether open-weight models (Gemma 2, Llama 3, Qwen 2.5) can safely replace expensive closed LLMs with honest statistics (10k bootstrap 95% CIs), default-deny provenance guard, calibrated pairwise judging, and LoRA fine-tuning break-even economics (DEV Hacktoberfest Open-Source AI Challenge Week 2: Side Hustle).





The project lives in the switchable/ folder. Key files:

How I Built It

  • Models: Gemma 2 (2B/9B), Llama 3.1/3.2, Qwen 2.5 7B via Ollama
  • Judge: every pair is scored in AB and BA order; disagreements are flagged (90% agreement with human labels, Îș = 0.85)
  • Provenance guard: blocks fine-tuning on closed-API outputs, then regenerates references with an open teacher
  • 109 tests, 10k-resample bootstrap CIs on every metric
Task Best open model Score [95% CI] Verdict
Support triage Qwen 2.5 7B + LoRA 90.0% [80, 98] ✅ Safe switch, 85% cheaper
Banking intent Gemma 2 2B 41.2% [27.5, 54.9] ❌ Not safe

The tool says "no" when the answer is no. That's the point.

Why Does Open Innovation Matter?

Closed APIs rent you a fine-tune. Open models give you a LoRA adapter you own forever. A $1.03 fine-tune broke even at ~10k requests/month, while 3-shot prompting quadrupled per-request cost.

My Agent Session

Built with Antigravity under a strict AGENTS.md: pre-flight gates, TDD, and a no-fabricated-metrics rule.

Prize Categories

  • Best Use of Gemma: 2B runs locally; 9B is the open teacher
  • Best Use of Tinker: LoRA training in 85s for $1.03
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