logging-conventions

name	logging-conventions
description	Logging and observability conventions (liberal debug logs,

Logging and observability

Applies to every language and runtime. The language skills restate the mechanics (library, level names, env var) where they need to be made concrete.

• Emit debug-level logs liberally wherever they help diagnose a problem after the fact: around every external / I/O call (log its inputs and its outcome), at each non-trivial decision branch, and at the boundaries of long or multi-step operations. The bar: a misbehaving program can be understood from its debug output alone, without adding logging and re-running.
• Reserve info for state transitions worth seeing at the default level; use warn / error for failures (with the cause).
• Diagnostic verbosity is controlled only by the log level (env var or config understood by the logging framework), never by a bespoke --verbose-style flag that gates whole code paths.
• Always log with structured fields/key-values, never by interpolating values into the message string. One log call should change what the reader knows; no noise, no secrets.
• Use the language's standard structured logging library, configured once at process start; never print/println/echo/console.log for diagnostics.