LLMON: An LLM-Native Markup Language, now in Granite 4.1 3B and 8B
IBM has introduced LLMON (LLM Object Notation), a new markup language designed to explicitly communicate structure and semantics to large language models. Built to address issues like prompt injection attacks and brittle behavior in smaller models, LLMON uses reserved special-token delimiters to mark semantically coherent components such as instructions, data, and requirements, enabling precise binding between them. Two experimental preview models—granite-4.1-3b-LLMON-preview and granite-4.1-8b-LLMON-preview—are now available, alongside a GitHub repository with conversion tools, workflows, and examples. LLMON enhances robustness by separating instruction from data, reducing indirect prompt injection success rates nearly to zero while maintaining performance comparable to standard Granite 4.1 Instruct models. It also supports custom schemas via LoRA fine-tuning, as demonstrated in ScienceWorld and tool-calling agent use cases. The approach is distinct from JSON, which lacks model-friendly structure, and complements existing chat templates by adding semantic clarity across roles.