Logging discipline

Even with a fancy platform, basic logging hygiene matters:

• Structured, not free-text. Log key-value fields (turn id, tool, document id, duration) so logs are queryable.
• Context on every error. A failure log should say which turn, which tool, which resource, and the error: enough to diagnose without reproducing.
• Never log secrets (Chapter 12) or sensitive document content; scrub them.
• Log decisions, not just outcomes. "Routed to mid-tier model because user has only a Gemini key" is more useful than "called Gemini."