AI article
We Fine-Tuned a 3B Model to Refuse Prompt Injections
Community description: If you're running LLMs in production, prompt injection is the attack you can't fully patch. Someone wraps "ignore your instructions" inside…
Dev.to | Mar 5, 2026 | Evangelos Pappas
Automated excerpt
Don't retrain benign behavior the base model already has. GRPO applied directly to the base model hit 0. 955 reward but 95% of training steps had zero gradient signal. Malicious prompts get paired with refusal responses.
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