Book: TypeScript in Production Also by me: The TypeScript Library — the 5-book collection My project: Hermes IDE | GitHub — an IDE for developers who ship with Claude Code and other AI coding tools Me: xgabriel.com | GitHub You have seen the shape of this incident before. A 500 lands in production. The frontend says "checkout failed". The Hono service that owns /checkout called the pricing service, which called the inventory service. Inventory is the one that timed out, but its logs are on a different host with a different clock skew, and no shared request id. The on-call engineer spends the next stretch of the morning tail-grepping log streams, trying to align them by guess. The version with OpenTelemetry wired in is different. You open the trace by request id, see the full span tree across all four services, and the slow span has a red border on inventory.reserve with the SKU and warehouse partition as attributes. The fix ships before the support inbox finishes loading.…