apps/ui, apps/cli: queue follow-up prompts during an active agent turn

apps/cli/ai/tests/ui.test.ts

@@ -194,6 +194,7 @@ describe( 'AiChatUI.clearTranscript', () => {
 		ui.currentMarkdown = { someMarkdown: true };
 		ui.currentResponseText = 'in-progress';
 		ui.hideLoader = vi.fn();
+		ui.queuedPrompts = [];
 
 		ui.clearTranscript();
 

apps/cli/ai/ui.ts

@@ -77,6 +77,18 @@ function formatToolOutputLines( lines: string[] ): string {
 		.join( '\n' );
 }
 
+// Faint variant of the user bubble used by `addUserMessage`, for prompts that
+// were staged during an active turn and haven't been dispatched yet.
+function formatQueuedPrompt( text: string ): string {
+	const lines = text.split( '\n' );
+	return lines
+		.map( ( line, i ) => {
+			const body = i === 0 ? '↳ ' + line + ' ' : '  ' + line + ' ';
+			return ' ' + chalk.bgHex( '#e8eef5' ).hex( '#5a6b7d' )( body );
+		} )
+		.join( '\n' );
+}
+
 class PromptEditor implements Component, Focusable {
 	private editor: Editor;
 	private borderColorFn: ( text: string ) => string;
@@ -365,6 +377,8 @@ export class AiChatUI implements AiOutputAdapter {
 	private editor: PromptEditor;
 	private loader: Loader;
 	private messages: Container;
+	private queuedContainer: Container;
+	private queuedPrompts: string[] = [];
 	private currentResponseText = '';
 	private currentMarkdown: Markdown | null = null;
 	private submitResolve: ( ( text: string ) => void ) | null = null;
@@ -476,6 +490,10 @@ export class AiChatUI implements AiOutputAdapter {
 		this.currentMarkdown = null;
 		this.currentResponseText = '';
 		this.messages.clear();
+		if ( this.queuedPrompts.length > 0 ) {
+			this.queuedPrompts = [];
+			this.renderQueuedContainer();
+		}
 		this.tui.requestRender();
 	}
 
@@ -497,6 +515,12 @@ export class AiChatUI implements AiOutputAdapter {
 		this.messages = new Container();
 		this.tui.addChild( this.messages );
 
+		// Always mounted just after `messages` and (once shown) just before the
+		// editor, so staged follow-up prompts render in that gap regardless of
+		// whether the loader is currently visible.
+		this.queuedContainer = new Container();
+		this.tui.addChild( this.queuedContainer );
+
 		this.loader = new Loader(
 			this.tui,
 			( str ) => chalk.yellow( str ),
@@ -537,10 +561,21 @@ export class AiChatUI implements AiOutputAdapter {
 
 		this.editor.onSubmit = ( text ) => {
 			const trimmed = text.trim();
-			if ( trimmed && this.submitResolve ) {
+			if ( ! trimmed ) {
+				return;
+			}
+			if ( this.submitResolve ) {
 				const resolve = this.submitResolve;
 				this.submitResolve = null;
 				resolve( trimmed );
+				return;
+			}
+			// No waiter → we're mid-turn. Stage the prompt so it fires after
+			// the current run ends; `waitForInput` drains the head.
+			if ( this._inAgentTurn ) {
+				this.queuedPrompts.push( trimmed );
+				this.editor.setText( '' );
+				this.renderQueuedContainer();
 			}
 		};
 		// Ctrl+C to exit, Escape to interrupt/close picker, arrow keys for picker
@@ -650,6 +685,19 @@ export class AiChatUI implements AiOutputAdapter {
 				this.renderSitePicker();
 				return { consume: true };
 			}
+			// Backspace on an empty editor pops the most recent queued prompt.
+			// Mirrors the × discard affordance in the GUI — lightweight undo
+			// for staged follow-ups without adding a new keybinding.
+			if (
+				matchesKey( data, 'backspace' ) &&
+				this.editorVisible &&
+				this.queuedPrompts.length > 0 &&
+				this.editor.getText() === ''
+			) {
+				this.queuedPrompts.pop();
+				this.renderQueuedContainer();
+				return { consume: true };
+			}
 			if ( matchesKey( data, 'escape' ) && this.interruptCallback ) {
 				this.wasInterrupted = true;
 				this.interruptCallback();
@@ -1203,6 +1251,11 @@ export class AiChatUI implements AiOutputAdapter {
 		this.editor.setText( '' );
 		this.hideLoader();
 		this.showEditor();
+		if ( this.queuedPrompts.length > 0 ) {
+			const next = this.queuedPrompts.shift()!;
+			this.renderQueuedContainer();
+			return Promise.resolve( next );
+		}
 		return new Promise( ( resolve ) => {
 			this.submitResolve = resolve;
 		} );
@@ -1222,6 +1275,15 @@ export class AiChatUI implements AiOutputAdapter {
 		this.tui.requestRender();
 	}
 
+	private renderQueuedContainer(): void {
+		this.queuedContainer.clear();
+		for ( const prompt of this.queuedPrompts ) {
+			this.queuedContainer.addChild( new Text( '\n' + formatQueuedPrompt( prompt ), 0, 0 ) );
+		}
+		this.updateHints();
+		this.tui.requestRender();
+	}
+
 	private lastProgressText: Text | null = null;
 
 	setLoaderMessage( message: string, update?: boolean ): void {
@@ -1240,12 +1302,16 @@ export class AiChatUI implements AiOutputAdapter {
 
 	private showLoader( message?: string ): void {
 		if ( ! this.loaderVisible ) {
-			// Ensure editor is removed first so loader appears above it
+			// Re-attach trailing children in order so the final stack is
+			// [..., loader, queuedContainer, editor?] — loader just above the
+			// staged follow-ups, which sit just above the editor.
 			const wasEditorVisible = this.editorVisible;
 			if ( wasEditorVisible ) {
 				this.tui.removeChild( this.editor );
 			}
+			this.tui.removeChild( this.queuedContainer );
 			this.tui.addChild( this.loader );
+			this.tui.addChild( this.queuedContainer );
 			if ( wasEditorVisible ) {
 				this.tui.addChild( this.editor );
 			}
@@ -1278,6 +1344,9 @@ export class AiChatUI implements AiOutputAdapter {
 				this.activeExpandablePreview.isExpanded ? __( 'ctrl+o collapse' ) : __( 'ctrl+o expand' )
 			);
 		}
+		if ( this.queuedPrompts.length > 0 ) {
+			hints.push( __( 'backspace to unqueue' ) );
+		}
 		hints.push( __( 'esc to interrupt' ) );
 		this.editor.hints = hints;
 	}

apps/ui/src/components/session-view/composer/index.tsx

@@ -3,35 +3,42 @@ import { useCallback, useState } from 'react';
 import styles from './style.module.css';
 
 interface ComposerProps {
-	disabled: boolean;
+	busy: boolean;
 	error: string | null;
 	onSend: ( prompt: string ) => Promise< void >;
 	onInterrupt: () => Promise< void >;
 }
 
-export function Composer( { disabled, error, onSend, onInterrupt }: ComposerProps ) {
+export function Composer( { busy, error, onSend, onInterrupt }: ComposerProps ) {
 	const [ value, setValue ] = useState( '' );
 
 	const send = useCallback( async () => {
 		const trimmed = value.trim();
-		if ( ! trimmed || disabled ) {
+		if ( ! trimmed ) {
 			return;
 		}
 		setValue( '' );
 		try {
 			await onSend( trimmed );
 		} catch {
 			// Restore the draft so the user can retry; the parent surfaces the
-			// error message via `error`.
+			// error message via `error`. Queued sends never throw from onSend
+			// (the parent swallows the failure and clears the queue instead),
+			// so this path only trips for direct sends from the idle state.
 			setValue( trimmed );
 		}
-	}, [ value, disabled, onSend ] );
+	}, [ value, onSend ] );
+
+	const placeholder = busy
+		? __( 'Queue a follow-up instruction…' )
+		: __( 'Set your next instruction…' );
+	const sendLabel = busy ? __( 'Queue' ) : __( 'Send' );
 
 	return (
 		<div className={ styles.root }>
 			<textarea
 				className={ styles.input }
-				placeholder={ __( 'Set your next instruction…' ) }
+				placeholder={ placeholder }
 				value={ value }
 				onChange={ ( event ) => setValue( event.target.value ) }
 				onKeyDown={ ( event ) => {
@@ -40,26 +47,24 @@ export function Composer( { disabled, error, onSend, onInterrupt }: ComposerProp
 						void send();
 					}
 				} }
-				disabled={ disabled }
 				rows={ 3 }
 			/>
 			<div className={ styles.footer }>
 				{ error ? <span className={ styles.error }>{ error }</span> : null }
 				<div className={ styles.actions }>
-					{ disabled ? (
+					{ busy ? (
 						<button type="button" className={ styles.button } onClick={ () => void onInterrupt() }>
 							{ __( 'Stop' ) }
 						</button>
-					) : (
-						<button
-							type="button"
-							className={ styles.button }
-							onClick={ () => void send() }
-							disabled={ ! value.trim() }
-						>
-							{ __( 'Send' ) }
-						</button>
-					) }
+					) : null }
+					<button
+						type="button"
+						className={ styles.button }
+						onClick={ () => void send() }
+						disabled={ ! value.trim() }
+					>
+						{ sendLabel }
+					</button>
 				</div>
 			</div>
 		</div>

apps/ui/src/components/session-view/index.tsx

@@ -3,6 +3,7 @@ import { clsx } from 'clsx';
 import { useLayoutEffect, useMemo, useRef } from 'react';
 import { Composer } from '@/components/session-view/composer';
 import { Conversation } from '@/components/session-view/conversation';
+import { QueuedPrompts } from '@/components/session-view/queued-prompts';
 import { SiteDropdown } from '@/components/site-dropdown';
 import { useAgentRun } from '@/data/queries/use-agent-run';
 import { useSession } from '@/data/queries/use-sessions';
@@ -53,9 +54,11 @@ export function SessionView( { sessionId }: { sessionId: string } ) {
 		error: runError,
 		pendingQuestions,
 		pendingAnswers,
+		queuedPrompts,
 		sendMessage,
 		interrupt,
 		answerQuestion,
+		removeQueuedPrompt,
 	} = useAgentRun( sessionId );
 	const pendingQuestionTexts = useMemo(
 		() => new Set( pendingQuestions.map( ( q ) => q.question ) ),
@@ -74,7 +77,7 @@ export function SessionView( { sessionId }: { sessionId: string } ) {
 			node.scrollTop = node.scrollHeight;
 		} );
 		return () => cancelAnimationFrame( id );
-	}, [ sessionId, data, isRunning ] );
+	}, [ sessionId, data, isRunning, queuedPrompts.length ] );
 
 	if ( isLoading ) {
 		return <div className={ styles.state }>{ __( 'Loading session…' ) }</div>;
@@ -106,8 +109,9 @@ export function SessionView( { sessionId }: { sessionId: string } ) {
 			</div>
 			<div className={ styles.composerOuter }>
 				<div className={ styles.column }>
+					<QueuedPrompts prompts={ queuedPrompts } onRemove={ removeQueuedPrompt } />
 					<Composer
-						disabled={ composerBusy }
+						busy={ composerBusy }
 						error={ runError }
 						onSend={ sendMessage }
 						onInterrupt={ interrupt }

apps/ui/src/components/session-view/queued-prompts/index.tsx

@@ -0,0 +1,32 @@
+import { __ } from '@wordpress/i18n';
+import styles from './style.module.css';
+import type { QueuedPrompt } from '@/data/queries/use-agent-run';
+
+interface QueuedPromptsProps {
+	prompts: QueuedPrompt[];
+	onRemove: ( id: string ) => void;
+}
+
+export function QueuedPrompts( { prompts, onRemove }: QueuedPromptsProps ) {
+	if ( prompts.length === 0 ) {
+		return null;
+	}
+	return (
+		<div className={ styles.root } aria-label={ __( 'Queued follow-ups' ) }>
+			{ prompts.map( ( item ) => (
+				<div key={ item.id } className={ styles.item }>
+					<span className={ styles.text }>{ item.prompt }</span>
+					<button
+						type="button"
+						className={ styles.remove }
+						onClick={ () => onRemove( item.id ) }
+						aria-label={ __( 'Discard queued follow-up' ) }
+						title={ __( 'Discard queued follow-up' ) }
+					>
+						×
+					</button>
+				</div>
+			) ) }
+		</div>
+	);
+}

apps/ui/src/components/session-view/queued-prompts/style.module.css

@@ -0,0 +1,61 @@
+.root {
+	display: flex;
+	flex-direction: column;
+	gap: var(--wpds-dimension-padding-sm);
+	margin-bottom: var(--wpds-dimension-padding-md);
+}
+
+.item {
+	position: relative;
+	align-self: flex-end;
+	display: flex;
+	align-items: flex-start;
+	gap: var(--wpds-dimension-padding-sm);
+	padding: var(--wpds-dimension-padding-md) var(--wpds-dimension-padding-lg);
+	/* Match the user bubble shape but lighter so staged follow-ups read as
+	   "drafted, not sent". Mirrors `.userText` (right-aligned, bottom-right
+	   tight corner). */
+	background-color: color-mix(in srgb, var(--wpds-color-fg-content-accent, #2563eb) 4%, transparent);
+	border: 1px dashed color-mix(in srgb, var(--wpds-color-fg-content-accent, #2563eb) 30%, transparent);
+	border-radius: 18px 18px var(--wpds-border-radius-md, 8px) 18px;
+	max-width: 80%;
+	font-size: var(--wpds-font-size-md);
+	line-height: 1.55;
+	color: var(--wpds-color-fg-content-neutral-weak);
+}
+
+.text {
+	flex: 1;
+	min-width: 0;
+	white-space: pre-wrap;
+	word-wrap: break-word;
+}
+
+.remove {
+	appearance: none;
+	flex-shrink: 0;
+	width: 22px;
+	height: 22px;
+	margin: -2px -6px -2px 0;
+	border: 0;
+	border-radius: 50%;
+	padding: 0;
+	background: transparent;
+	color: var(--wpds-color-fg-content-neutral-weak);
+	font: inherit;
+	font-size: 16px;
+	line-height: 1;
+	cursor: pointer;
+	opacity: 0.6;
+}
+
+.item:hover .remove,
+.remove:focus-visible {
+	opacity: 1;
+}
+
+.remove:hover,
+.remove:focus-visible {
+	background-color: color-mix(in srgb, var(--wpds-color-fg-content-accent, #2563eb) 12%, transparent);
+	color: var(--wpds-color-fg-content-neutral);
+}