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Last updated: September 2026
Agent drift is a recurring change in behavior that appears across production sessions. It may look like ignored constraints, a longer tool path, repeated calls, a rise in poor results, or a successful execution that no longer produces a useful outcome.
Do not start with one suspicious trace
One trace can show an anomaly. Drift is a pattern. Start by comparing behavior across sessions, users, intents, environments, models, or release identifiers that your traces already carry.
Look for three forms of drift
Instruction drift
The agent begins ignoring scope, safety, or policy constraints it previously followed.
Tool-path drift
A formerly direct task starts repeating calls, taking longer paths, or accumulating failed calls.
Outcome drift
Calls still complete, but users receive worse results, abandon the session, or leave negative feedback.
Use issue evidence
Flowlines includes drifting among its behavior issue categories. An issue connects the pattern to what happened, why it matters, a suggested next step, technical detection details, where it fires, and evidence sessions.
For MCP systems, journey analysis adds calls per session, loop events, failed sessions, typical tool paths, and outcome context. A journey with successful calls but many loops is a strong example of why status alone is not enough.
Compare releases honestly
If you add a release or prompt identifier to trace properties, Flowlines Groups can compare the sessions that share it. Treat a before-and-after difference as evidence, not automatic proof of causality. Check traffic mix, environment, and use case, then inspect the sessions behind the change.
Close the loop
Make one change, preserve the same trace context, and observe whether the issue recurs. The goal is not a prettier dashboard. It is a shorter path from an unknown production outcome to a verified cause.
Learn about production comparisons or see MCP journey analysis.