"use client";
import {
useEffect,
useEffectEvent,
useId,
useImperativeHandle,
useLayoutEffect,
useRef,
useState,
type KeyboardEvent,
type PointerEvent,
type Ref,
} from "react";
import { focusQuietly } from "@/design-system";
import { hostTransport, play, type PlayOptions, type SoundName } from "@/lib/sound";
/*
* An agent's run on a recorder's readout: an LCD in a well, three lights for
* the phases it passes through, an ALLOW key and a transport cap.
*
* The chip says the state with the LCD's own glyphs. A live run is the
* transport rolling, so it pulses red like every study that runs by itself;
* an error is the same red in the stop's square, so shape tells it from a
* live run even where nothing pulses; a run waiting on you is orange, the
* colour of a hand. Nothing on the glass is red text.
*
* The clock counts the time the run is live, in minutes, seconds and frames.
* It holds, dimmed, while the run waits on you, and STOP freezes it on the
* frame the key goes down. The light that's firing flickers with each chunk
* of tokens through a one-pole detector (90ms), so a stream shimmers and a
* stall goes quiet while the clock keeps counting. Both are drawn from one
* frame loop straight to the DOM, which stops while nothing moves or the
* readout is off-screen. No spring: nothing here travels.
*
* Tab reaches the cap (and ALLOW while it's lit); Escape stops a run. Each
* change is said once in a polite live region, an error in an alert. Under
* reduced motion nothing pulses or flickers and the clock counts whole seconds.
*/
export type AgentState = "ready" | "thinking" | "tool" | "writing" | "waiting" | "done" | "error" | "stopped";
/** What the agent is doing: "Read" "take_04.wav". */
export type AgentStep = { verb: string; target?: string };
export type AgentKey = "run" | "stop" | "allow";
export type AgentStatusHandle = { press: (key: AgentKey) => void };
type AgentStatusProps = {
state: AgentState;
/** What it's doing, waiting on, or what went wrong. */
step?: AgentStep | null;
/** Tokens so far this run. Each rise kicks the firing light; leave it out and the light burns steady and no count shows. */
tokens?: number;
/** Seconds the run has been live, to restore or correct the clock. Between changes it counts on while live and holds otherwise. */
elapsed?: number;
/** STOP, or Escape: interrupts a live or waiting run. Set the state to "stopped" straight away. */
onStop?: () => void;
/** RUN from ready, done or stopped; RETRY after an error. */
onRun?: () => void;
/** ALLOW: lets a waiting run go on. Leave it out and the key isn't drawn. */
onAllow?: () => void;
label?: string;
ref?: Ref<AgentStatusHandle>;
className?: string;
};
type Phase = "thinking" | "tool" | "writing";
type Light = "off" | "set" | "fire" | "hold" | "fault";
const PHASES: { key: Phase; name: string }[] = [
{ key: "thinking", name: "Think" },
{ key: "tool", name: "Tool" },
{ key: "writing", name: "Write" },
];
const DECAY = 0.09; // s: the detector's release
const FLOOR = 0.35; // the firing light's glow with no tokens arriving
const cx = (...parts: (string | false | undefined)[]) => parts.filter(Boolean).join(" ");
const isLive = (s: AgentState | null): s is Phase => s === "thinking" || s === "tool" || s === "writing";
/** A live state entered from one of these starts a fresh run. */
const isEnd = (s: AgentState | null) => s === null || s === "ready" || s === "done" || s === "error" || s === "stopped";
const reducedMotion = () => matchMedia("(prefers-reduced-motion: reduce)").matches;
const thousands = (n: number) => String(n).replace(/\B(?=(\d{3})+(?!\d))/g, ",");
const lineOf = (step?: AgentStep | null) => (step ? [step.verb, step.target].filter(Boolean).join(" ") : "");
/** Lettering on the body: tiny tracked capitals, cut in. */
const engraved = "font-semibold uppercase leading-none tracking-[0.16em] [text-shadow:var(--device-engrave)]";
/** Drawn, what the glass dims is ink at a lower strength. */
const dimmed = "drawn:text-[color-mix(in_oklab,var(--device-draw-ink)_70%,transparent)]!";
/** A key's face: it sinks onto its base under the hand, or while `data-pressed` (the keyboard, the ghost). */
const sink =
"group-active/key:translate-y-[2px] group-active/key:shadow-(--device-key-shadow-pressed) group-active/key:duration-75 group-data-pressed/key:translate-y-[2px] group-data-pressed/key:shadow-(--device-key-shadow-pressed) group-data-pressed/key:duration-75";
/** Writes seconds into the clock as minutes, seconds and frames at 25 fps, touching only the fields that change. */
function paintClock(el: HTMLElement, seconds: number) {
const frames = Math.floor(seconds * 25);
const parts = [Math.floor(frames / 1500) % 100, Math.floor(frames / 25) % 60, frames % 25];
for (let i = 0; i < 3; i++) {
const node = el.children[i * 2];
const text = String(parts[i]).padStart(2, "0");
if (node && node.textContent !== text) node.textContent = text;
}
}
/** The cue for a change of state: one existing voice, varied by pitch and gain. */
function soundFor(from: AgentState, to: AgentState, lineChanged: boolean, tools: number): [SoundName, PlayOptions] | null {
if (isLive(to)) {
if (from === "waiting") return ["select", { gain: 0.45 }];
if (!isLive(from)) return ["start", { gain: 0.8 }];
if (from !== to) return ["toggle", { gain: 0.45 }];
// Each tool call a detent a little higher, like the hold's ratchet.
if (to === "tool" && lineChanged) return ["tick", { gain: 0.55, pitch: 0.92 + 0.04 * Math.min(tools, 8) }];
return null;
}
if (from === to) return null;
if (to === "waiting") return ["open", { gain: 0.5, pitch: 1.05 }];
if (to === "done") return ["select", { gain: 0.6 }];
if (to === "error") return ["bump", { gain: 0.9 }];
if (to === "stopped") return ["stop", { gain: 0.8 }];
return null;
}
/** What a screen reader hears for a state. */
function sayFor(state: AgentState, line: string) {
const with_ = (word: string) => (line ? `${word}: ${line}` : word);
if (state === "thinking") return with_("Thinking");
if (state === "tool") return line || "Running a tool";
if (state === "writing") return with_("Writing");
if (state === "waiting") return with_("Waiting for your OK");
if (state === "done") return with_("Done");
if (state === "error") return with_("Error");
if (state === "stopped") return "Stopped";
return "";
}
/** The chip's glyph says the state before its word does. Drawn, red stays for what runs and what fails; the rest are ink, orange being the drawing's own. */
function ChipGlyph({ state }: { state: AgentState }) {
if (isLive(state)) return <span className="size-[0.55em] animate-pulse rounded-full bg-(--device-rec) motion-reduce:animate-none drawn:bg-(--device-rec)!" />;
if (state === "waiting") return <span className="size-[0.55em] rounded-full bg-(--device-hold) drawn:bg-(--device-draw-ink)!" />;
if (state === "error") return <span className="size-[0.5em] rounded-[1px] bg-(--device-rec) drawn:bg-(--device-rec)!" />;
if (state === "stopped") return <span className="size-[0.5em] rounded-[1px] bg-current drawn:bg-(--device-draw-ink)!" />;
return <span className="size-[0.55em] rounded-full bg-black drawn:bg-(--device-draw-ink)!" />;
}
/** The run so far, worked out from each change of state as it renders. */
type Track = { state: AgentState; line: string; at: Phase | null; seen: Phase[]; tools: number; said: number };
export function AgentStatus({ state, step, tokens, elapsed, onStop, onRun, onAllow, label = "Agent", ref, className }: AgentStatusProps) {
const line = lineOf(step);
const ids = useId();
const rootRef = useRef<HTMLDivElement>(null);
const clockRef = useRef<HTMLParagraphElement>(null);
const lineRef = useRef<HTMLSpanElement>(null);
const engine = useRef<{ go: (live: boolean, fresh: boolean) => void; reset: () => void; seek: (s: number) => void; kick: (n: number) => void } | null>(null);
const touched = useRef(false); // a hand has worked it: it sounds even while the host is paused
const heard = useRef<"start" | "stop" | null>(null); // a key already played the cue the next change would
const metered = useRef(tokens !== undefined);
useLayoutEffect(() => {
metered.current = tokens !== undefined;
});
const [track, setTrack] = useState<Track>(() => ({
state,
line,
at: isLive(state) ? state : state === "waiting" ? "tool" : null,
seen: isLive(state) ? [state] : [],
tools: state === "tool" || state === "waiting" ? 1 : 0,
said: 0,
}));
// Each change is read off as it renders: the phase the lights follow, the phases passed and the tool calls made.
if (state !== track.state || line !== track.line) {
const fresh = state === "ready" || (isLive(state) && isEnd(track.state));
const resumed = track.state === "waiting" && line === track.line; // ALLOW: the same call goes on
const at = isLive(state) ? state : state === "waiting" ? "tool" : state === "ready" ? null : track.at;
const seen = fresh ? [] : track.seen;
// A new tool call: one asking for your OK is the same call when it goes on.
const call = (state === "tool" || state === "waiting") && !resumed && (line !== track.line || (track.state !== "tool" && track.state !== "waiting"));
setTrack({
state,
line,
at,
seen: at && !seen.includes(at) ? [...seen, at] : seen,
tools: (fresh ? 0 : track.tools) + (call ? 1 : 0),
said: track.said + 1,
});
}
const live = isLive(state);
const waiting = state === "waiting";
const canStop = (live || waiting) && !!onStop;
const canRun = !live && !waiting && !!onRun;
const cap = canStop ? "Stop" : state === "error" ? "Retry" : "Run";
/** Sounds it makes by itself follow the host's transport; the hand's always play. */
function sound(name: SoundName, options?: PlayOptions) {
if (touched.current || hostTransport(rootRef.current) === "play") play(name, options);
}
// The clock and the firing light, drawn from one frame loop that runs only while something moves.
useLayoutEffect(() => {
const root = rootRef.current!;
const clock = clockRef.current!;
const reduced = reducedMotion();
let banked = 0; // live seconds before the current stretch
let since = 0; // when the current live stretch began, or 0 while held
let env = 0; // the detector: 1 as tokens land, falling at DECAY
let last = 0;
let raf = 0;
let seen = true;
const draw = (now: number) => {
const t = banked + (since ? (now - since) / 1000 : 0);
// Whole seconds while live under reduced motion: the frames would race.
paintClock(clock, reduced && since ? Math.floor(t) : t);
root.style.setProperty("--act", (!metered.current ? 1 : reduced ? 0.7 : FLOOR + (1 - FLOOR) * env).toFixed(3));
};
const frame = (now: number) => {
env *= Math.exp(-Math.min(100, now - last) / 1000 / DECAY);
if (env < 0.002) env = 0;
last = now;
draw(now);
raf = since || env ? requestAnimationFrame(frame) : 0;
};
const wake = () => {
if (raf || !seen || !(since || env)) return;
last = performance.now();
raf = requestAnimationFrame(frame);
};
const visibility = new IntersectionObserver(([entry]) => {
seen = entry.isIntersecting;
if (seen) wake();
else {
cancelAnimationFrame(raf);
raf = 0;
}
});
visibility.observe(root);
engine.current = {
go(isLive, fresh) {
const now = performance.now();
if (fresh) banked = 0;
if (isLive && !since) since = now;
else if (!isLive && since) {
banked += (now - since) / 1000;
since = 0;
}
draw(now);
wake();
},
reset() {
banked = 0;
since = 0;
draw(performance.now());
},
seek(s) {
const now = performance.now();
banked = s;
if (since) since = now;
draw(now);
},
kick(n) {
if (reduced) return;
env = Math.max(env, Math.min(1, 0.5 + n / 24));
wake();
},
};
draw(performance.now());
return () => {
cancelAnimationFrame(raf);
visibility.disconnect();
};
}, []);
// A change of state starts, holds or zeroes the clock. A live state entered from an end is a fresh run.
const was = useRef<AgentState | null>(null);
useLayoutEffect(() => {
const from = was.current;
was.current = state;
if (state === "ready") engine.current!.reset();
else engine.current!.go(isLive(state), isLive(state) && isEnd(from));
}, [state]);
// After the state's effect, so a restored time lands on the clock it set up.
useLayoutEffect(() => {
if (elapsed !== undefined) engine.current!.seek(elapsed);
}, [elapsed]);
const tokensWere = useRef(tokens);
useEffect(() => {
const from = tokensWere.current;
tokensWere.current = tokens;
if (tokens !== undefined && from !== undefined && tokens > from) engine.current!.kick(tokens - from);
}, [tokens]);
// The step line types on, a letter per step, as a new one arrives.
const typed = useRef(line);
useLayoutEffect(() => {
if (typed.current === line) return;
typed.current = line;
const el = lineRef.current;
if (!el || !line || reducedMotion()) return;
el.animate([{ clipPath: "inset(0 100% 0 0)" }, { clipPath: "inset(0 0 0 0)" }], {
duration: Math.min(480, Math.max(160, line.length * 18)),
easing: `steps(${Math.min(line.length, 48)})`,
});
}, [line]);
// One cue per change; none on mount. A key that already played its cue isn't heard twice.
const cue = useEffectEvent((from: AgentState, lineChanged: boolean) => {
const next = soundFor(from, state, lineChanged, track.tools);
const skip = heard.current;
heard.current = null;
if (next && next[0] !== skip) sound(...next);
});
const shown = useRef({ state, line });
useEffect(() => {
const from = shown.current;
if (from.state === state && from.line === line) return;
shown.current = { state, line };
cue(from.state, from.line !== line);
}, [state, line]);
/* --- Keys --------------------------------------------------------------- */
function act(key: AgentKey) {
if (key === "stop" && canStop) {
heard.current = "stop";
sound("stop", { gain: 0.8 });
onStop?.();
} else if (key === "run" && canRun) {
heard.current = "start";
sound("start", { gain: 0.8 });
onRun?.();
} else if (key === "allow" && waiting) onAllow?.();
}
/** Shows a key held down, or let up. */
function hold(key: AgentKey, down: boolean) {
rootRef.current?.querySelector(`[data-key="${key === "allow" ? "allow" : "cap"}"]`)?.toggleAttribute("data-pressed", down);
}
useImperativeHandle(ref, () => ({
press(key) {
hold(key, true);
setTimeout(() => hold(key, false), 140);
// ALLOW clicks through `data-sound` under a hand; pressed from outside, it clicks here.
if (key === "allow" && waiting) {
sound("press", { gain: 0.7 });
setTimeout(() => sound("release", { gain: 0.6 }), 140);
}
act(key);
},
}));
function onKeyDown(e: KeyboardEvent<HTMLDivElement>) {
// Escape stops a run; with nothing to stop it's left alone, so a host can take the keyboard back.
if (e.key !== "Escape" || !canStop) return;
e.preventDefault();
if (e.repeat) return;
hold("stop", true);
act("stop");
}
function onKeyUp(e: KeyboardEvent<HTMLDivElement>) {
if (e.key === "Escape") hold("stop", false);
}
/** Focus follows the hand: no ring, and the keys pick up where it left off. */
const focusOnPress = (e: PointerEvent<HTMLElement>) => {
if (e.button === 0) focusQuietly(e.currentTarget);
};
/* --- Render ------------------------------------------------------------- */
const lightOf = (phase: Phase): Light => {
if (phase === track.at && state !== "done") return live ? "fire" : waiting ? "hold" : state === "error" ? "fault" : "set";
return track.seen.includes(phase) && state !== "ready" ? "set" : "off";
};
const word = state === "tool" && track.tools ? `Tool ${track.tools}` : { ready: "Ready", thinking: "Thinking", tool: "Tool", writing: "Writing", waiting: "Waiting", done: "Done", error: "Error", stopped: "Stopped" }[state];
const said = track.said ? sayFor(state, line) : "";
const allow = !!onAllow;
const unit = cx("ml-[0.1em] mr-[0.45em] text-[0.3em] font-normal text-(--device-lcd-dim) last:mr-0", dimmed);
return (
<div
ref={rootRef}
role="group"
aria-label={label}
onPointerDownCapture={() => (touched.current = true)}
onKeyDownCapture={() => (touched.current = true)}
onKeyDown={onKeyDown}
onKeyUp={onKeyUp}
className={cx(
"@container/agent grid w-full items-center gap-x-[0.6em] gap-y-[0.8em]",
allow ? "grid-cols-[minmax(0,1fr)_auto] @[24rem]/agent:grid-cols-[minmax(0,1fr)_auto_auto]" : "grid-cols-[minmax(0,1fr)_auto]",
className,
)}
>
{/* The readout: an LCD in a well. It mirrors what the live region says, so it stays out of the reading order. */}
<div data-part="well" className={cx("rounded-[1.05em] bg-(--device-well) p-[0.4em] shadow-(--device-recess)", allow ? "col-span-2 @[24rem]/agent:col-span-3" : "col-span-2")}>
<div
aria-hidden
data-part="lcd"
className="relative flex flex-col gap-[0.5em] overflow-hidden rounded-[0.7em] px-[0.8em] pb-[0.65em] pt-[0.6em] text-(--device-lcd-ink) [background:var(--device-lcd)] shadow-(--device-lcd-edge)"
>
<div className="flex items-center gap-[0.55em]">
<span data-part="chip" className="inline-flex shrink-0 items-center gap-[0.35em] rounded-[0.4em] bg-white px-[0.42em] py-[0.24em] text-black">
<ChipGlyph state={state} />
<span className="text-[0.58em] font-semibold uppercase leading-none tracking-[0.02em] tabular-nums">{word}</span>
</span>
{tokens !== undefined && state !== "ready" && (
<span className={cx("ml-auto truncate text-[0.66em] tabular-nums text-(--device-lcd-dim)", dimmed)}>{thousands(tokens)} tokens</span>
)}
</div>
{/* The clock: the frame loop writes the figures; the units stay put. */}
<p
ref={clockRef}
className={cx(
"flex items-baseline whitespace-nowrap text-[2.1em] font-light leading-none tracking-[-0.03em] tabular-nums transition-colors duration-(--duration-exit) @[24rem]/agent:text-[2.35em]",
waiting && cx("text-(--device-lcd-dim)", dimmed),
)}
>
<span>00</span>
<span className={unit}>M</span>
<span>00</span>
<span className={unit}>S</span>
<span>00</span>
<span className={unit}>F</span>
</p>
<p className={cx("h-[1.25em] min-w-0 text-[0.92em] leading-[1.25] tracking-[-0.01em]", state === "stopped" && cx("text-(--device-lcd-dim)", dimmed))}>
<span ref={lineRef} id={`${ids}-line`} className="inline-block max-w-full truncate align-top">
{step?.verb}
{step?.target && <span className={cx("text-(--device-lcd-dim)", dimmed)}> {step.target}</span>}
{state === "writing" && (
<span className="ml-[0.12em] inline-block h-[0.95em] w-[0.08em] translate-y-[0.14em] animate-caret bg-current motion-reduce:animate-none drawn:bg-(--device-draw-ink)!" />
)}
</span>
</p>
</div>
</div>
{/* The phases: each latches once the run has passed it; the one firing flickers with the tokens. */}
<div
aria-hidden
className={cx(
"flex items-center justify-between px-[0.4em]",
allow ? "col-span-2 @[24rem]/agent:col-span-1 @[24rem]/agent:justify-start @[24rem]/agent:gap-[1.2em]" : "justify-start gap-[1.2em]",
)}
>
{PHASES.map(({ key, name }) => (
<span key={key} data-light={lightOf(key)} className="group/light flex items-center gap-[0.5em]">
<span data-part="well" className="grid size-[0.78em] shrink-0 place-items-center rounded-full bg-black/[0.05] shadow-(--device-recess) dark:bg-black/40">
<span data-part="light" className="relative size-[0.44em] rounded-full bg-(--device-meter-off) transition-[background-color] duration-(--duration-exit) group-data-[light=fault]/light:bg-(--device-rec) group-data-[light=fault]/light:duration-0 group-data-[light=fire]/light:bg-(--device-rec) group-data-[light=fire]/light:duration-0 group-data-[light=hold]/light:bg-(--device-hold) group-data-[light=hold]/light:duration-0 group-data-[light=set]/light:bg-(--device-meter-on) drawn:group-data-[light=set]/light:bg-(--device-draw-ink)!">
{/* The glow on its own layer, so the flicker is never smoothed by the light's fade. Drawn, it is the fill that fires: red while firing or faulting (the flicker is its strength), ink while held. */}
<span className="absolute inset-0 rounded-full opacity-0 shadow-[0_0_0.45em_var(--device-rec)] transition-opacity duration-(--duration-exit) group-data-[light=fault]/light:opacity-100 group-data-[light=fire]/light:opacity-(--act) group-data-[light=fire]/light:transition-none group-data-[light=hold]/light:opacity-100 group-data-[light=hold]/light:shadow-[0_0_0.5em_var(--device-hold)] drawn:bg-(--device-rec)! drawn:group-data-[light=hold]/light:bg-(--device-draw-ink)!" />
</span>
</span>
<span data-part="lettering" className={cx(engraved, "text-[0.6em] text-(--device-label-quiet) group-data-[light=fault]/light:text-(--device-label) group-data-[light=fire]/light:text-(--device-label) group-data-[light=hold]/light:text-(--device-label)")}>
{name}
</span>
</span>
))}
</div>
{/* ALLOW: its light glows while a call waits on you. */}
{allow && (
<button
type="button"
data-key="allow"
data-sound="key"
aria-disabled={!waiting}
aria-describedby={`${ids}-line`}
tabIndex={waiting ? 0 : -1}
onPointerDown={(e) => waiting && focusOnPress(e)}
onClick={() => act("allow")}
data-part="key"
className={cx("group/key min-w-0 rounded-[0.7em] outline-offset-2 @[24rem]/agent:w-[7.5em]", !waiting && "cursor-default")}
>
<span
className={cx(
"relative grid h-[2.7em] place-items-center rounded-[0.7em] text-(--device-key-ink) [background:var(--device-key-face)] shadow-(--device-key-shadow) transition-[transform,box-shadow] duration-(--duration-exit) ease-out",
waiting && sink,
)}
>
<span
aria-hidden
data-part="light"
className={cx(
"absolute left-1/2 top-[0.42em] h-[0.24em] w-[2.3em] -translate-x-1/2 rounded-full",
waiting ? "bg-(--device-hold) shadow-[0_0_0.45em_var(--device-hold)] drawn:bg-(--device-draw-ink)!" : "bg-(--device-meter-off) transition-[background-color] duration-(--duration-exit)",
)}
/>
<span data-part="lettering" className="mt-[0.45em] text-[0.8em] font-medium uppercase leading-none tracking-[0.03em] [text-shadow:var(--device-engrave)]">Allow</span>
</span>
</button>
)}
{/* The transport: STOP while it runs or waits, PLAY to run it again. A white cap in a collar. */}
<button
type="button"
data-key="cap"
aria-label={cap}
aria-disabled={!canStop && !canRun}
aria-keyshortcuts={canStop ? "Escape" : undefined}
tabIndex={canStop || canRun ? 0 : -1}
onPointerDown={focusOnPress}
onClick={() => act(canStop ? "stop" : "run")}
data-part="collar"
className={cx("group/key grid size-[3.3em] shrink-0 place-items-center rounded-full bg-black/[0.035] p-[0.26em] shadow-(--device-recess) outline-offset-2 dark:bg-black/30", allow ? "col-start-2 @[24rem]/agent:col-start-3" : "col-start-2")}
>
<span data-part="cap" className={cx("grid size-full place-items-center rounded-full [background:var(--device-wheel-face)] shadow-(--device-key-shadow) transition-[transform,box-shadow] duration-(--duration-exit) ease-out", (canStop || canRun) && sink)}>
{canStop ? (
<span aria-hidden data-part="lettering" className="size-[0.85em] rounded-[0.14em] bg-(--device-key-ink) drawn:bg-(--device-draw-ink)!" />
) : (
<svg aria-hidden data-part="lettering" viewBox="0 0 16 16" className="ml-[0.12em] size-[1.2em] fill-(--device-rec)">
<path d="M4.5 2.4 13.2 8l-8.7 5.6z" />
</svg>
)}
</span>
</button>
{/* Said once per change; the paragraph is keyed so the same words can be said again. */}
<div role="status" className="sr-only">
<p key={track.said}>{state === "error" ? "" : said}</p>
</div>
<p role="alert" className="sr-only">
{state === "error" ? said : ""}
</p>
</div>
);
}
/* --- Demo: an agent tidying a recorder's session, and a ghost at the keys ------ */
type Cue = { wait: number; state: AgentState; verb: string; target?: string } | { wait: number; ghost: "stop" };
type Script = { task: AgentStep; cues: Cue[]; retry?: Cue[] };
const cue = (wait: number, state: AgentState, verb: string, target?: string): Cue => ({ wait, state, verb, target });
const RUNS: Script[] = [
{
task: { verb: "Tidy", target: "session_12" },
cues: [
cue(0, "thinking", "Planning", "the tidy-up"),
cue(950, "tool", "Read", "take_04.wav"),
cue(600, "tool", "Search", "room tone · 6 takes"),
cue(600, "thinking", "Comparing", "take_02, take_03"),
cue(650, "tool", "Delete", "take_03.wav"),
cue(120, "waiting", "Delete", "take_03.wav"),
// Allowed: the same call goes on.
cue(0, "tool", "Delete", "take_03.wav"),
cue(600, "tool", "Trim", "take_04.wav · 1.8 s"),
cue(600, "writing", "Writing", "session notes"),
cue(1700, "done", "Tidied", "5 takes · 1 deleted"),
],
},
{
task: { verb: "Export", target: "take_05.wav" },
cues: [
cue(0, "thinking", "Planning", "the export"),
cue(900, "tool", "Normalize", "take_05.wav · −1 dB"),
cue(700, "tool", "Export", "take_05.wav · 48 kHz"),
cue(1100, "error", "Card full", "2.1 GB short"),
],
retry: [
cue(0, "thinking", "Freeing", "2.1 GB"),
cue(800, "tool", "Move", "take_01–03 to SSD"),
cue(700, "tool", "Export", "take_05.wav · 48 kHz"),
cue(900, "done", "Exported", "take_05.wav"),
],
},
{
task: { verb: "Write", target: "notes for take_04" },
cues: [
cue(0, "thinking", "Planning", "the notes"),
cue(800, "tool", "Read", "markers · take_04"),
cue(600, "writing", "Writing", "notes for take_04"),
// The ghost stops it mid-stream; under a hand, the agent finishes.
{ wait: 1500, ghost: "stop" },
cue(1500, "done", "Wrote", "notes · 212 words"),
],
},
];
/** How long the ghost waits at each state before it presses a key. */
const GHOST: Partial<Record<AgentState, number>> = { ready: 700, waiting: 1500, error: 2200, done: 2600, stopped: 2000 };
const FIRST_PRESS = 280; // ms: the first RUN lands while the plate is still entering
/** Tokens per 90ms chunk: a thinking trickle, a writing stream. */
const chunk = (state: AgentState) => (state === "writing" ? 8 + Math.floor(Math.random() * 13) : 3 + Math.floor(Math.random() * 7));
export default function Demo() {
const [state, setState] = useState<AgentState>("ready");
const [step, setStep] = useState<AgentStep>(RUNS[0].task);
const [tokens, setTokens] = useState(0);
const [elapsed, setElapsed] = useState<number>();
const [run, setRun] = useState(0);
const [ghost, setGhost] = useState(false);
const rootRef = useRef<HTMLDivElement>(null);
const status = useRef<AgentStatusHandle>(null);
const agent = useRef<ReturnType<typeof setTimeout>>(undefined);
const rest = useRef<Cue[]>([]); // what the agent does once it's allowed to go on
const live = useRef(false); // the ghost is at the keys
const touched = useRef(false); // a real hand has been here: the ghost doesn't come back
const first = useRef(true);
/** The agent works through its cues; a call that needs your OK waits there. */
function perform(cues: Cue[]) {
clearTimeout(agent.current);
const [next, ...more] = cues;
if (!next) return;
const go = () => {
if ("ghost" in next) {
if (live.current) status.current?.press("stop");
else perform(more);
return;
}
setState(next.state);
setStep({ verb: next.verb, target: next.target });
if (next.state === "waiting") rest.current = more;
else perform(more);
};
if (next.wait) agent.current = setTimeout(go, next.wait);
else go();
}
function start(cues: Cue[]) {
setTokens(0);
perform(cues);
}
function onRun() {
if (state === "error") return start(RUNS[run].retry ?? RUNS[run].cues);
if (state === "ready") return start(RUNS[run].cues);
const next = (run + 1) % RUNS.length;
setRun(next);
start(RUNS[next].cues);
}
function onStop() {
clearTimeout(agent.current);
setState("stopped");
}
/** Puts the next task up on the readout. */
function cueUp() {
const next = (run + 1) % RUNS.length;
setRun(next);
setState("ready");
setStep(RUNS[next].task);
setTokens(0);
}
/** Any real input takes over from the ghost, for good. The run in flight finishes, or waits for the hand. */
function takeOver() {
touched.current = true;
if (!live.current) return;
live.current = false;
setGhost(false);
}
// Tokens arrive in chunks while it thinks or writes; a tool call is quiet.
useEffect(() => {
if (state !== "thinking" && state !== "writing") return;
const id = setInterval(() => setTokens((t) => t + chunk(state)), 90);
return () => clearInterval(id);
}, [state]);
// The ghost: RUN on a ready task, ALLOW on a call that waits, RETRY on an error, then the next task.
const press = useEffectEvent(() => {
if (!live.current) return;
if (state === "ready" || state === "error") status.current?.press("run");
else if (state === "waiting") status.current?.press("allow");
else if (state === "done" || state === "stopped") cueUp();
});
useEffect(() => {
if (!ghost || GHOST[state] === undefined) return;
const wait = state === "ready" && first.current ? FIRST_PRESS : GHOST[state];
first.current = false;
const id = setTimeout(press, wait);
return () => clearTimeout(id);
}, [ghost, state, run]);
// On power-up the ghost runs the first task, unless the host's tape is stopped: then it waits for PLAY.
// Under reduced motion it shows one still frame, a call waiting on you, for the hand to answer.
const powerUp = useEffectEvent(() => {
if (reducedMotion()) {
const at = RUNS[0].cues.findIndex((c) => "state" in c && c.state === "waiting");
rest.current = RUNS[0].cues.slice(at + 1);
setState("waiting");
setStep({ verb: "Delete", target: "take_03.wav" });
setTokens(412);
setElapsed(4.48);
return;
}
if (touched.current || live.current || hostTransport(rootRef.current) === "stop") return;
live.current = true;
setGhost(true);
});
useEffect(() => {
const root = rootRef.current;
const id = setTimeout(powerUp, 0);
const host = root?.closest("[data-transport]");
const observer = new MutationObserver(() => hostTransport(root) === "play" && powerUp());
if (host) observer.observe(host, { attributes: true, attributeFilter: ["data-transport"] });
const pending = agent;
return () => {
clearTimeout(id);
observer.disconnect();
clearTimeout(pending.current);
live.current = false;
};
}, []);
return (
<div ref={rootRef} onPointerDownCapture={takeOver} onKeyDownCapture={takeOver} onFocusCapture={takeOver} className="@container w-full max-w-[440px] select-none">
<div data-part="plate" className="relative isolate animate-enter overflow-hidden rounded-[1.25em] p-[0.9em] text-[clamp(11px,4cqw,14px)] [background:var(--device-body)] shadow-[var(--device-body-edge),0_1px_2px_rgb(0_0_0/0.06),0_16px_32px_-18px_rgb(0_0_0/0.3)] @[26rem]:p-[1.1em]">
<div aria-hidden className="device-grain pointer-events-none absolute inset-0 -z-10 rounded-[inherit]" />
<AgentStatus
ref={status}
state={state}
step={step}
tokens={tokens}
elapsed={elapsed}
onRun={onRun}
onStop={onStop}
onAllow={() => perform(rest.current)}
/>
</div>
</div>
);
}
