Lesson 25 / 28

Monitoring, Detection and Logging

Watch for abuse in production without creating a privacy problem.

Signals worth watching

In production, log enough to investigate and detect: requests per user, blocked or flagged inputs, canary-token hits (prompt leakage), policy denials and approval outcomes, tool calls with arguments (redacted), refusals, validation failures, token and cost per user and feature, and latency and error rates. Alert on anomalies: bursts of injection-like inputs, a user repeatedly hitting denials, a sudden jump in cost or tool calls, tools called in unusual sequences, new outbound hosts contacted, or outputs containing secrets or personal data. Balance this with privacy: redact sensitive values, restrict who can read logs, apply retention limits and treat logs as sensitive data. Detection does not stop an attack by itself, so connect it to response: the ability to block a user, disable a tool or feature, and roll back a prompt or model.

Alerts worth having

Thresholds are examples; tune to your traffic.

Signal                                         Example alert rule
canary token appears in an output              any hit -> page security, block the response
>= 5 policy denials by one user in 10 min      flag the account for review
tool calls per request > 3x normal             investigate possible loop or injection
cost per hour > 3x the 7-day baseline          alert + automatic spend cap
new outbound hostname from a tool              alert; require approval before allowing
secret/PII pattern in model output             block, redact, alert

Alert on cost spikes

A sudden jump in spend is often the first sign of abuse or a runaway loop.

Quick check: A canary token from the system prompt appears in a reply. What does it indicate?

  • The model is faster
  • Everything is fine
  • The system prompt was leaked and the response should be blocked and reviewed
  • The user is a developer
Answer

The system prompt was leaked and the response should be blocked and reviewed — Canaries turn silent leakage into a detectable event.