Observability and Instrumentation Overview Code you can't observe is code you can't operate. Observability is the ability to answer "what is the system doing and why?" from the outside, using the telemetry the code emits. Instrumentation is not a post-launch add-on — it's written alongside the feature, the same way tests are. If a feature ships without telemetry, the first user-reported bug becomes archaeology instead of a query. When to Use - Building any feature that will run in production - Adding a new service, endpoint, background job, or external integration - A production incident took…