When LLM JSON Outputs Fail: A Rust Solution for Production-Grade Reliability

Claude Sonnet's structured JSON output has a 14% failure rate despite explicit prompts, causing parsing errors in production systems. The llm-json-repair Rust crate solves this without additional API calls by applying three-pass local cleanup: stripping code fences, extracting balanced braces, and fixing trailing commas. This approach saves development time and improves reliability for high-volume LLM integrations.