# Shadcn Trace > Open-source shadcn trace components for agent reasoning, tool calls and run steps that expand to their output. - Type: shadcn/ui component, free - Page: https://reui.io/components/trace - Docs (Base UI): https://ui.shadcn.com/docs/components/base/trace.md - Docs (Radix UI): https://ui.shadcn.com/docs/components/radix/trace.md - MCP: `get_component("trace")`, then `get_examples("trace")` - Examples: 22 ## When to use - Agent turns: reasoning, tool calls, subagents and the sources behind an answer - Run logs that expand to output, from CI jobs and data builds to webhook deliveries - Checklists of automated checks or setup steps with running, failed and pending states ## When not to use - One short status line per step with no expanding detail or status color: use [Marker](https://reui.io/components/marker.md) (`get_component("marker")`) - Dated events or milestones joined by a connecting line: use [Timeline](https://reui.io/components/timeline.md) (`get_component("timeline")`) - A complete run console with approvals, log views and an outcome report: use the [Agent Activity blocks](https://reui.io/blocks/ai-agents/agent-activity.md) ## Agent notes - Status is shown by color and motion only, so every `TraceTitle` must also say in words that a step is running, failed or not started - A `TraceLine` on its own is a plain span; wrap it in a link or a Dialog, Sheet or Popover trigger to make it act ## Examples - [Agent Steps](https://reui.io/components/trace/c-trace-1.md): Agent steps. Best for a plain search line, a diff and test output that expand, a lint failure and a running fix, in one bare column. - [Streaming Run](https://reui.io/components/trace/c-trace-2.md): Streaming agent run. Best for a run that streams its reasoning and resolves tool steps on a timer, with a Stop button and live rows that open themselves. - [Chat Turn](https://reui.io/components/trace/c-trace-3.md): Chat turn with sources. Best for a chat transcript turn whose 2 SQL queries fold into one summary row above the answer, with cited dashboards below. - [Subagents](https://reui.io/components/trace/c-trace-4.md): Parallel subagents. Best for a parent row over 3 subagents whose status is computed from its children, plus a retry for the failed one. - [Change Approval](https://reui.io/components/trace/c-trace-5.md): Terraform change approval. Best for a human approval gate where planned resource rows switch from pending to running to applied in place after Apply. - [Cited Sources](https://reui.io/components/trace/c-trace-6.md): Answer with citations. Best for inline citation buttons wired to a controlled sources row, focusing the cited link once its panel mounts. - [Support Copilot](https://reui.io/components/trace/c-trace-7.md): Support copilot draft. Best for a drafted support reply in its own row after 3 order and policy lookups, with Insert and Regenerate below. - [Install Summary](https://reui.io/components/trace/c-trace-8.md): CLI install summary. Best for a finished install summary with registry items, packages, created files as links, one kept file and a CSS diff. - [CI Pipeline](https://reui.io/components/trace/c-trace-9.md): CI pipeline run. Best for a workflow run of 4 jobs where the failed test job opens to its log and a re-run replays test, build and deploy. - [Request Spans](https://reui.io/components/trace/c-trace-10.md): Distributed trace spans. Best for spans nested under their parent, each opening to its OpenTelemetry attributes, with the slowest span marked by its share. - [Error Breadcrumbs](https://reui.io/components/trace/c-trace-11.md): Error breadcrumbs. Best for an exception's timestamped user and network events, a response body in a Dialog and folded React stack lines. - [Query Plan](https://reui.io/components/trace/c-trace-12.md): SQL query plan. Best for a recursive tree of plan nodes, each opening to its numbers and children, with the slowest node flagged by its share. - [Data Pipeline](https://reui.io/components/trace/c-trace-13.md): Data pipeline run. Best for built models folded into one row, a failing data test open on its duplicate keys, and a skipped downstream model. - [Webhook Retries](https://reui.io/components/trace/c-trace-14.md): Webhook delivery attempts. Best for a delivery log of failed and successful attempts, each opening to its response or payload, plus a Resend action. - [CSV Import](https://reui.io/components/trace/c-trace-15.md): CSV import. Best for a spreadsheet upload whose last step counts up live while rejected rows sit in a Table with a download link. - [Security Audit](https://reui.io/components/trace/c-trace-16.md): Dependency audit. Best for a list of 3 advisories with severity badges, each opening to its dependency chain and the one action that fixes it. - [Review Findings](https://reui.io/components/trace/c-trace-17.md): AI review findings. Best for flagged lines that each open in a Sheet with a suggested diff, then read as applied or dismissed in place. - [Eval Results](https://reui.io/components/trace/c-trace-18.md): Model eval results. Best for scored cases with a failures only switch, each failure opening to a compact expected, got and judge list. - [Access Decision](https://reui.io/components/trace/c-trace-19.md): Access decision. Best for a permission decision as the parent row of its rules, recomputed from 2 Selects, with rules after the decider not reached. - [Identity Review](https://reui.io/components/trace/c-trace-20.md): Identity verification. Best for an applicant review with automated document and screening checks, one rejection and a request for a new document. - [Domain Setup](https://reui.io/components/trace/c-trace-21.md): Domain DNS setup. Best for a setup checklist with copyable DNS records, a lookup per record, then a pending go live step. - [Transcode](https://reui.io/components/trace/c-trace-22.md): Media transcode. Best for a media pipeline with 3 renditions encoding in parallel under one row, followed by thumbnail and publish steps. Every ReUI item has a twin like this one; the index is https://reui.io/llms.txt. Agents with the ReUI MCP (https://reui.io/docs/mcp) get the same guidance from the getters named above.