# Monitor LLM drift

Know when a surface’s model starts answering differently, even while every request still succeeds, and test a candidate model against real captured traffic before it takes any live share. Field-level reference for every setting here is in [LLM drift →](/products/affinidi-trust-fabric/agent-stream/reference/observability/llm-drift.md).

| Guide | What you will achieve |
| [Detect LLM drift and set a baseline](/products/affinidi-trust-fabric/agent-stream/how-to-guides/drift/detect-llm-drift-and-set-a-baseline.md) | Add the Drift Harness to an LLM Surface, pin a baseline of its normal behaviour, and get an alert when refusals, latency, cost, or other dimensions move past your thresholds. |
| [Replay captured traffic against a candidate model](/products/affinidi-trust-fabric/agent-stream/how-to-guides/drift/replay-captured-traffic-against-a-candidate.md) | Run a surface’s captured prompts through another surface or a variant with a different model, and compare the answers with the baseline before any live traffic moves to it. |

## Pages in this section
- [Detect LLM drift and set a baseline](/products/affinidi-trust-fabric/agent-stream/how-to-guides/drift/detect-llm-drift-and-set-a-baseline.md): Add the Drift Harness to an LLM Surface, pin a baseline of its normal behaviour, and get an alert when refusals, latency, cost, or other dimensions move past your thresholds.
- [Replay captured traffic against a candidate model](/products/affinidi-trust-fabric/agent-stream/how-to-guides/drift/replay-captured-traffic-against-a-candidate.md): Run a surface's captured prompts through another surface or a variant with a different model, and compare the answers with the baseline before any live traffic moves to it.