> ## Documentation Index > Fetch the complete documentation index at: https://hobbyist-e43fa225.mintlify.site/llms.txt > Use this file to discover all available pages before exploring further. # Review agent interactions with Trace Replay > Learn how to use Trace Replay in Microsoft Foundry to navigate, filter, and analyze conversation traces from agent runs. Items marked (preview) in this article are currently in public preview. This preview is provided without a service-level agreement, and we don't recommend it for production workloads. Certain features might not be supported or might have constrained capabilities. For more information, see [Supplemental Terms of Use for Microsoft Azure Previews](https://azure.microsoft.com/support/legal/preview-supplemental-terms/). Trace Replay in Microsoft Foundry enables you to inspect, navigate, and analyze conversation traces from agent runs. It can be accessed from any page that references a **Conversation ID** or **Trace ID**. Traces can be visualized as a **User view** for reviewing the user's perspective of the agent interactions, or a **Trajectories view** for understanding span hierarchy and timing. These views, combined with interactive replay controls and filtering, help you understand execution flow, identify bottlenecks, and troubleshoot issues. ## Prerequisites * A [Foundry project](../../how-to/create-projects) with at least one [agent](/agents/overview). * Trace data collected for the target agent. If you haven't set up tracing yet, see [Set up tracing in Microsoft Foundry](/observability/trace-agent-setup). * Access to the Application Insights resource connected to your project. For background, see [Azure Monitor Application Insights](https://learn.microsoft.com/azure/azure-monitor/app/app-insights-overview). * A Log Analytics reader role to view traces, insights, and visualizations in Foundry. ## Use cases | Scenario | How Trace Replay helps | | ------------------------------- | ---------------------------------------------------------------------------------- | | **Root cause analysis** | Quickly identify failures or bottlenecks in agent conversations. | | **Token usage optimization** | Spot spans with high token consumption to optimize agent prompts and reduce costs. | | **Debugging** | Replay execution step-by-step to understand failures or unexpected behaviors. | | **Conversation reconstruction** | Visualize the entire conversation flow for audits or reviews. | ## Open the Replay Panel 1. Sign in to [Microsoft Foundry](https://ai.azure.com). 2. Navigate to the **Traces** page under your agent. 3. Select a **Conversation ID** or **Trace ID** to open the Replay Panel. The Replay Panel opens, showing the Trajectories view by default. ## Explore the Replay Panel views The Replay Panel provides two complementary views of a trace. To switch between them, select the **Trajectories** or **User** tab at the top of the Replay Panel. In both views, you can select any span to inspect the step in the agent loop, including LLM invocations, tool execution, user prompts, sub-agent orchestrations and responses. You can also view raw metadata as JSON and see the results of any evaluations that ran as part of this conversation. ### Trajectories view Screenshot of the Trace Replay panel showing the Trajectories view with a hierarchical span tree. Each span displays a waterfall bar measured by duration. The Trajectories view renders the trace as a hierarchical tree, showing every step in the user and agent interaction — including agent reasoning, tool calls, and conversation turns. Each span displays a waterfall bar that can be measured by either **duration** or **token cost**, making it straightforward to compare the relative expense of each step. This view is most useful for identifying potential agentic failures such as errors, hallucinations, and abnormally long or costly interactions. ### User view Screenshot of the Trace Replay panel showing the User view tab active, with a chat-based conversation between the user and agent displayed. The User view presents the trace as a chat-based visualization of the interactions between the user and agent, reflecting what the end user would have experienced. A collapsible **Span tree** panel remains accessible alongside the chat, so you can cross-reference the underlying span hierarchy without leaving this view. ## Filter traces Screenshot of the filter dropdown in Trace Replay, showing span type options (Chat, Agent, Tool, Conversation) and token range options (Low, Medium, High). 1. In the Replay Panel, select the **Filter** control. 2. Choose one or more span types from the list to narrow the trace. The span tree updates to show only spans matching the selected types. | Filter | Shows | | ---------------- | -------------------------------------------------- | | **Chat** | Chat-specific spans in the trace | | **Agent** | Agent invocation | | **Tool** | Any tool executions that occurred during the trace | | **Conversation** | Conversation-specific spans in the trace | To search by span name, enter text in the **Find in trace** field. ### Filter by token consumption Filter spans by token usage level to identify hotspots or outliers. | Level | Description | | ---------- | ----------------------------------------------------------------------- | | **Low** | Less than 500 tokens | | **Medium** | 500–2k tokens | | **High** | More than 2k tokens — useful for identifying outliers in the trace loop | ## Replay a conversation Screenshot of the Trace Replay panel showing the Playthrough control bar at the bottom with play, skip, and speed controls. The **Playthrough** control replays the entire conversation sequentially, keeping the Trajectories view, User view, and span detail panel in sync as each step is highlighted. 1. Select **Play** in the **Playthrough** control at the bottom of the Replay Panel. 2. Use the playback controls as needed: * **Skip spans** at any point to jump ahead in the interaction. * **Adjust playback speed** (for example, 1x, 2x, or 4x) to move through long traces faster. * **Scrub to any point** in the trace using the timeline scrubber to seek directly to a specific moment without replaying from the beginning. The Replay Panel highlights each span in sequence across both the Trajectories view and the span detail panel. ## Troubleshoot | Symptom | Resolution | | ----------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------- | | Conversation ID or Trace ID isn't visible | Tracing isn't configured for this agent. See [Set up tracing in Microsoft Foundry](/observability/trace-agent-setup). | | Replay Panel loads but shows no spans | The trace might still be processing. Wait a few minutes, then refresh the page. | | **Playthrough** control is unavailable | Playthrough requires two or more spans. Single-span traces can't be replayed sequentially. | | Filter applied but no spans are visible | The selected filter type doesn't appear in this trace. Clear the filter and try a broader span type, or verify that the agent uses the filtered capability. | ## Related content * [Agent tracing overview](/observability/trace-agent-concept) * [Monitor agents with the Agent Monitoring Dashboard](/agents/how-to-monitor-agents-dashboard) * [Set up tracing in Microsoft Foundry](/observability/trace-agent-setup) * [Tracing integrations](/observability/trace-agent-framework)