We Rewrote Our Zig 0.11 Code in Rust 1.85: Cut Bug Count by 40% A production case study of migrating a high-throughput telemetry agent from Zig 0.11 to Rust 1.85, including migration hurdles, quantitative results, and hard-won lessons. Our Zig 0.11 Codebase: Context and Pain Points Our team maintains a distributed systems telemetry agent deployed on 12k+ production nodes, processing ~100k events per second per instance. We originally wrote the agent in Zig 0.11 in 2023, drawn to its minimal runtime, bare-metal compatibility, and comptime metaprogramming for zero-cost abstractions. For 6 months, the codebase performed well: average latency of 12μs per event, 0.01% CPU overhead per node. But as we scaled the team from 2 to 5 engineers and added new features (e.g., OpenTelemetry export, custom sampling rules), Zig's limitations became unignorable: Memory safety gaps: Zig's manual memory management led to 14 use-after-free and double-free bugs in 6 months, accounting for 35% of all production incidents.…