Structured filesystem error reporting for build systems

Modern build systems increasingly fail because of filesystem-level issues—race conditions, permissions, ENOSPC, stale caches and file-locking—that produce noisy, opaque logs and waste developer and CI time. This problem hits monorepo and large-codebase environments hardest: platform engineers, CI maintainers and developer productivity teams at organizations of tens to thousands of engineers where a single IO failure can block hundreds of builds and slow delivery. A practical product would define a typed FsError schema and lightweight instrumentation (a native Rust agent plus language SDKs) that normalizes OS-specific errors into structured, queryable events, shipping contextual metadata (operation, path, inode/mount info, process) and offering CLI/CI plugins, a local dev CLI and an optional cloud or self-hosted backend for aggregation, alerting and runbook links. You could start with a permissively-licensed core library and command-line tooling, then monetize via paid enterprise integrations (Bazel/Turborepo/Nx, Docker, Kubernetes PVs) and a hosted analytics tier aimed at the broader $18B developer tooling market (25M developers, ~$720/yr average spend) with an emphasis on platform budgets. Engineering challenges are real—cross-platform normalization, keeping overhead negligible in hot paths, and handling path/privacy concerns—plus the non-trivial task of getting build-tool maintainers to adopt hooks. Timing favors this effort: monorepo adoption raises the impact of IO failures, observability-first teams want structured, queryable events rather than opaque logs, and the growth of Rust-based tooling makes fast, typed integrations feasible. With medium competition, the clearest differentiators are a rigorous, open FsError standard, first-class integrations for leading build systems, and a low-overhead native agent; proceed if you can land 2–3 pilot customers to validate integration complexity and pricing, otherwise be prepared for meaningful GTM and engineering effort before scale.