OpenRouter Structured Output Broke Before Translation Quality Did — 3 Layers of Defense for Production

The article describes a production incident where an LLM started wrapping JSON responses in Markdown code fences, breaking JSON.parse() and taking down a translation feature. The author built a 3-layer defense system using json_object response format, OpenRouter's response-healing plugin, and a custom defensive parser to stabilize structured output. Additional topics include retry/fallback strategies for HTTP errors and language detection challenges for tech content.