Waterfall timeline for AI agent runs with a replay scrubber: drag the playhead and spans fill, statuses flip from queued to running to done, token counts tick up. Nested sub-agents, retries, errors. No chart library, keyboard-accessible, theme tokens.
"use client"
import { motion, useReducedMotion } from "motion/react"
// Relative import on purpose: the 21st CLI rewrites it to the published path (`@/components/ui/<slug>`)
// and to a temporary path during `21st render`. An absolute "@/…" import breaks the render build.
import { AgentTrace, type TraceSpan } from "@/components/ui/agent-trace"
// A real coding-agent run: plan, gather in parallel, hand off to a reviewer sub-agent, fail the test
// suite, repair, retry, commit. Durations and token counts are internally consistent.
const RUN: TraceSpan[] = [
{ id: "plan", label: "model.plan", kind: "model", start: 0, end: 740, tokens: 1240, detail: "4 steps" },
{ id: "search", label: "search_docs", kind: "tool", start: 780, end: 1960, detail: "12 matches" },
{ id: "read-session", label: "read_file", kind: "io", start: 1120, end: 1480, status: "cached", detail: "session.ts" },
{ id: "read-token", label: "read_file", kind: "io", start: 1180, end: 1610, detail: "token.ts" },
{ id: "reviewer", label: "agent.reviewer", kind: "agent", start: 2000, end: 5400, tokens: 4820, detail: "2 issues" },
{ id: "grep", label: "grep", kind: "tool", parentId: "reviewer", start: 2060, end: 2340, detail: "9 hits" },
{ id: "review", label: "model.review", kind: "model", parentId: "reviewer", start: 2380, end: 4900, tokens: 3480, detail: "412 lines" },
{ id: "note", label: "write_note", kind: "io", parentId: "reviewer", start: 4940, end: 5320, detail: "notes.md" },
{ id: "tests-1", label: "run_tests", kind: "tool", start: 5460, end: 7180, status: "error", detail: "2 failing" },
{ id: "repair", label: "model.repair", kind: "model", start: 7220, end: 8600, tokens: 2110, detail: "3 edits" },
{ id: "tests-2", label: "run_tests", kind: "tool", start: 8640, end: 9900, attempt: 2, detail: "42 passed" },
{ id: "commit", label: "commit", kind: "io", start: 9940, end: 10400, detail: "3 files" },
]
const TOTAL = 10400
// Module-level `settings` + a default export that accepts them as props gives this demo a live
// controls panel on 21st.dev. Signature knobs first, then look, then copy.
const settings = {
speed: 1,
// Paused at 62% on purpose. 21st captures the cover a few seconds after load, so an autoplaying
// loop makes the cover a lottery — land just after a restart and it is a grey card of queued rows.
// Paused, every capture is this frame: the failed run_tests solid red, the retry mid-flight. It also
// turns the recorded video beat into a click that *starts* the sweep instead of one that stops it.
autoPlay: false,
loop: true,
startAt: 0.62,
rowHeight: 34,
labelWidth: 200,
showRuler: true,
showTransport: true,
showTokens: true,
eyebrow: "Agent observability",
headline: "See what the agent actually did.",
subline: "Twelve spans, one failed test suite, one retry. Drag the timeline to replay the run.",
}
export default function Demo(props: Partial<typeof settings>) {
const s = { ...settings, ...props }
const reduce = useReducedMotion()
const enter = (delay: number) =>
reduce
? {}
: {
initial: { opacity: 0, y: 14, filter: "blur(6px)" },
animate: { opacity: 1, y: 0, filter: "blur(0px)" },
transition: { duration: 0.6, delay, ease: [0.22, 1, 0.36, 1] as const },
}
return (
<div className="bg-background flex min-h-[max(560px,100svh)] w-full flex-col items-center justify-center px-5 py-16 sm:px-8">
<div className="flex w-full max-w-4xl flex-col items-center">
<motion.p
{...enter(0)}
className="text-muted-foreground border-border mb-5 inline-flex items-center gap-2 rounded-full border px-3 py-1 text-xs font-medium"
>
<span aria-hidden="true" className="bg-primary size-1.5 rounded-full" />
{s.eyebrow}
</motion.p>
<motion.h1
{...enter(0.08)}
className="text-foreground text-center text-4xl font-semibold tracking-tight text-balance sm:text-5xl"
>
{s.headline}
</motion.h1>
<motion.p
{...enter(0.16)}
className="text-muted-foreground mt-4 max-w-2xl text-center text-sm text-balance sm:text-base"
>
{s.subline}
</motion.p>
<motion.div {...enter(0.24)} className="mt-10 w-full">
<AgentTrace
id="agent-trace-demo"
spans={RUN}
duration={TOTAL}
runId="run_7c41f2"
model="claude-opus-5"
defaultTime={s.startAt * TOTAL}
autoPlay={s.autoPlay}
loop={s.loop}
speed={s.speed}
rowHeight={s.rowHeight}
labelWidth={s.labelWidth}
showRuler={s.showRuler}
showTransport={s.showTransport}
showTokens={s.showTokens}
/>
</motion.div>
</div>
</div>
)
}