feat: render flow chat mode through the AI session chat components

Flow chat mode drew its own bubbles from chat/ChatMessage and chat/ChatInput
while the AI session chat rendered the same kinds of message far better a
directory away. FlowChatViewHost maps a flow run's conversation onto
ChatViewHost, so both now render through AIChatDisplay.

Flow chat gains thinking blocks, workspace-path links, collapsible tool cards,
the typing indicator, scroll-to-latest, and queueing a message typed while the
run is in flight. FlowChatManager keeps its conversations, SSE and polling
untouched; the sidebar, the inputs modal and its localStorage are unchanged.

An assistant message can carry the flow step that produced it, rendered only
when a conversation holds more than one distinct step — with a single agent the
label repeats on every message and says nothing. It is counted over the
transcript rather than the flow's current steps, since a conversation outlives
edits to the flow. AssistantMessage also renders a windmill_s3_object result
through DisplayResult, as chat/ChatMessage did.

FlowChatInterface claims a min-height once there are messages: the editor's
Test-flow panel stacks the chat above the job result in an auto-height column,
where the transcript's absolute scroller would otherwise resolve to zero.

chat/ChatMessage and chat/ChatInput stay for AppChat and its customCss hooks.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Hw1yzWHyqqZmQrviUEhr5b

frontend/src/lib/components/copilot/chat/AssistantMessage.svelte

@@ -13,6 +13,7 @@
 		workspaceItemRegistry
 	} from './workspaceItems.svelte'
 	import { markdownProse } from '$lib/components/markdownProse'
+	import DisplayResult from '$lib/components/DisplayResult.svelte'
 
 	interface Props {
 		message: DisplayMessage
@@ -58,6 +59,20 @@
 		return rest === 0 ? `${minutes}m` : `${minutes}m ${rest}s`
 	}
 
+	const stepName = $derived(message.role === 'assistant' ? message.stepName : undefined)
+
+	// A flow step can return a file rather than text; the raw JSON would be
+	// unreadable, so hand it to the result viewer instead of the markdown renderer.
+	const s3Object = $derived.by(() => {
+		if (!message.content.startsWith('{')) return undefined
+		try {
+			const parsed = JSON.parse(message.content)
+			return parsed?.type === 'windmill_s3_object' && parsed?.s3 ? parsed : undefined
+		} catch {
+			return undefined
+		}
+	})
+
 	const candidatePaths = $derived(extractCandidatePaths(message.content))
 	const rendererPlugin = {
 		renderer: {
@@ -111,7 +126,13 @@
 	</ChatCollapsibleCard>
 {/if}
 
-{#if message.content}
+{#if stepName}
+	<div class="text-2xs text-tertiary font-medium mb-1">{stepName}</div>
+{/if}
+
+{#if s3Object}
+	<DisplayResult result={s3Object} workspaceId={$workspaceStore} noControls={true} />
+{:else if message.content}
 	<div class="w-full space-y-2 {markdownProse.sm}">
 		<Markdown md={message.content} {plugins} />
 	</div>

frontend/src/lib/components/copilot/chat/shared.ts

@@ -629,6 +629,9 @@ export type AssistantDisplayMessage = BaseDisplayMessage & {
 	 * would look like it is still streaming forever.
 	 */
 	streaming?: boolean
+	/** Flow step that produced this message, when the conversation is a flow run
+	 * rather than a copilot turn. Rendered as a label above the content. */
+	stepName?: string
 }
 
 /**

frontend/src/lib/components/flows/conversations/FlowChat.svelte

@@ -17,6 +17,8 @@
 		path: string
 		hideSidebar?: boolean
 		inputSchema?: Record<string, any>
+		/** Wider centered column, for the full-page chat. */
+		wideLayout?: boolean
 	}
 
 	let {
@@ -25,7 +27,8 @@
 		useStreaming = false,
 		path,
 		hideSidebar = false,
-		inputSchema = undefined
+		inputSchema = undefined,
+		wideLayout = false
 	}: Props = $props()
 
 	const flowEditorContext = getContext<FlowEditorContext>('FlowEditorContext')
@@ -72,5 +75,11 @@
 	{#if !hideSidebar}
 		<FlowConversationsSidebar {manager} />
 	{/if}
-	<FlowChatInterface {manager} {deploymentInProgress} {additionalInputsSchema} {path} />
+	<FlowChatInterface
+		{manager}
+		{deploymentInProgress}
+		{additionalInputsSchema}
+		{path}
+		{wideLayout}
+	/>
 </div>

frontend/src/lib/components/flows/conversations/FlowChatInterface.svelte

@@ -1,9 +1,10 @@
 <script lang="ts">
-	import { Alert, Button } from '$lib/components/common'
-	import { MessageCircle, Loader2, Settings2 } from 'lucide-svelte'
-	import ChatMessage from '$lib/components/chat/ChatMessage.svelte'
-	import ChatInput from '$lib/components/chat/ChatInput.svelte'
+	import { Button } from '$lib/components/common'
+	import { Loader2, MessageCircle, Settings2 } from 'lucide-svelte'
 	import { FlowChatManager } from './FlowChatManager.svelte'
+	import { FlowChatViewHost } from './flowChatViewHost.svelte'
+	import AIChatDisplay from '$lib/components/copilot/chat/AIChatDisplay.svelte'
+	import { setChatViewHost } from '$lib/components/copilot/chat/chatViewHost'
 	import Modal from '$lib/components/common/modal/Modal.svelte'
 	import SchemaForm from '$lib/components/SchemaForm.svelte'
 	import { type DynamicInput } from '$lib/utils'
@@ -13,9 +14,16 @@
 		deploymentInProgress?: boolean
 		additionalInputsSchema?: Record<string, any>
 		path: string
+		wideLayout?: boolean
 	}
 
-	let { manager, deploymentInProgress = false, additionalInputsSchema, path }: Props = $props()
+	let {
+		manager,
+		deploymentInProgress = false,
+		additionalInputsSchema,
+		path,
+		wideLayout = false
+	}: Props = $props()
 
 	// Derive helperScript for dynamic inputs from schema
 	const dynamicInputHelperScript = $derived.by((): DynamicInput.HelperScript | undefined => {
@@ -63,19 +71,24 @@
 		showInputsModal = false
 	}
 
-	function handleSendMessage() {
-		const inputs = additionalInputsSchema
-			? (loadInputsFromStorage() ?? additionalInputsValues)
-			: undefined
-		manager.sendMessage(inputs)
-	}
-
 	function openInputsModal() {
 		const stored = loadInputsFromStorage()
 		if (stored) additionalInputsValues = stored
 		showInputsModal = true
 	}
 
+	const chatHost = new FlowChatViewHost(manager, () =>
+		additionalInputsSchema ? (loadInputsFromStorage() ?? additionalInputsValues) : undefined
+	)
+	setChatViewHost(chatHost)
+
+	// A message typed mid-run is held by the host; send it once the run settles.
+	$effect(() => {
+		if (!chatHost.loading && chatHost.queuedMessage) {
+			chatHost.flushQueuedMessage()
+		}
+	})
+
 	const hasMissingRequired = $derived.by(() => {
 		if (!additionalInputsSchema?.required?.length) return false
 		const values = additionalInputsValues ?? {}
@@ -101,83 +114,65 @@
 	</Modal>
 {/if}
 
-<div class="flex flex-col h-full flex-1 min-w-0">
-	<!-- Messages Container -->
-	<div
-		bind:this={manager.messagesContainer}
-		class="flex-1 min-h-0 overflow-y-auto p-4 bg-background"
-		onscroll={manager.handleScroll}
-	>
-		{#if deploymentInProgress}
-			<Alert type="warning" title="Deployment in progress" size="xs" />
-		{/if}
+{#snippet emptyHint()}
+	<div class="flex-1 text-center text-tertiary flex items-center justify-center flex-col">
 		{#if manager.isLoadingMessages}
-			<div class="flex items-center justify-center h-full">
-				<Loader2 size={32} class="animate-spin" />
-			</div>
-		{:else if manager.messages.length === 0}
-			<div class="text-center text-tertiary flex items-center justify-center flex-col h-full">
-				<MessageCircle size={48} class="mx-auto mb-4 opacity-50" />
-				<p class="text-lg font-medium">Start a conversation</p>
-				<p class="text-sm">Send a message to run the flow and see the results</p>
-			</div>
+			<Loader2 size={32} class="animate-spin" />
 		{:else}
-			<div class="w-full space-y-4 xl:max-w-7xl mx-auto">
-				{#each manager.messages as message (message.id)}
-					<ChatMessage
-						role={message.message_type}
-						content={message.content}
-						loading={message.loading}
-						success={message.success}
-						stepName={message.step_name}
-					/>
-				{/each}
-				{#if manager.isWaitingForResponse}
-					<div class="flex items-center gap-2 text-tertiary">
-						<Loader2 size={16} class="animate-spin" />
-						<span class="text-sm">Processing...</span>
-					</div>
+			<MessageCircle size={48} class="mx-auto mb-4 opacity-50" />
+			<p class="text-lg font-medium">Start a conversation</p>
+			<p class="text-sm">Send a message to run the flow and see the results</p>
+		{/if}
+	</div>
+{/snippet}
+
+{#snippet inputPreface()}
+	{#if additionalInputsSchema}
+		<div class="flex items-center justify-end w-full mb-1">
+			<div class="relative">
+				<Button
+					unifiedSize="xs"
+					variant="default"
+					startIcon={{ icon: Settings2 }}
+					title="Inputs"
+					onClick={openInputsModal}
+				>
+					Inputs
+				</Button>
+				{#if hasMissingRequired}
+					<span class="absolute -top-1 -right-1 w-2 h-2 bg-yellow-500 rounded-full"></span>
 				{/if}
 			</div>
-		{/if}
-	</div>
-
-	<!-- Chat Input -->
-	<div class="flex flex-col items-center p-2 xl:max-w-7xl mx-auto w-full gap-2">
-		{#if additionalInputsSchema}
-			<div class="flex items-center justify-end w-full">
-				<div class="relative">
-					<Button
-						size="xs"
-						variant="default"
-						startIcon={{ icon: Settings2 }}
-						title="Inputs"
-						onClick={openInputsModal}
-					>
-						Inputs
-					</Button>
-					{#if hasMissingRequired}
-						<span class="absolute -top-1 -right-1 w-2 h-2 bg-yellow-500 rounded-full"></span>
-					{/if}
-				</div>
-			</div>
-		{/if}
-		<div class="w-full" class:opacity-50={deploymentInProgress}>
-			<ChatInput
-				bind:value={manager.inputMessage}
-				bind:bindTextarea={manager.inputElement}
-				disabled={manager.isLoading || deploymentInProgress}
-				onSend={handleSendMessage}
-				onKeydown={(e) => {
-					if (e.key === 'Enter' && !e.shiftKey && !e.isComposing) {
-						e.preventDefault()
-						handleSendMessage()
-					}
-				}}
-				showCancelButton={manager.isWaitingForResponse || manager.isLoading}
-				onCancel={() => manager.cancelCurrentJob()}
-				sendTitle={deploymentInProgress ? 'Deployment in progress' : 'Send message (Enter)'}
-			/>
 		</div>
-	</div>
+	{/if}
+{/snippet}
+
+<!-- The transcript scroller fills its flex row, which needs a height to resolve
+     against. Not every host gives one (the editor's Test-flow panel stacks the
+     chat above the job result in an auto-height column), so once there are
+     messages to scroll, claim one. -->
+<div
+	class="flex flex-col h-full flex-1 min-w-0"
+	class:min-h-96={chatHost.displayMessages.length > 0}
+>
+	<AIChatDisplay
+		messages={chatHost.displayMessages}
+		bind:scrollElement={manager.messagesContainer}
+		onTranscriptScroll={manager.handleScroll}
+		pastChats={[]}
+		diffMode={false}
+		selectedContext={[]}
+		availableContext={[]}
+		hideHeader
+		hideModeSelector
+		{wideLayout}
+		{emptyHint}
+		{inputPreface}
+		placeholder="Send a message to run the flow"
+		disabled={deploymentInProgress}
+		disabledMessage="Deployment in progress"
+		loadPastChat={() => {}}
+		deletePastChat={() => {}}
+		saveAndClear={() => {}}
+	/>
 </div>

frontend/src/lib/components/flows/conversations/flowChatViewHost.svelte.ts

@@ -0,0 +1,156 @@
+import type {
+	ChatSendRequestOptions,
+	ChatViewHost
+} from '$lib/components/copilot/chat/chatViewHost'
+import type { DisplayMessage } from '$lib/components/copilot/chat/shared'
+import type { ChatMessage, FlowChatManager } from './FlowChatManager.svelte'
+import { AIAutonomyMode } from '$lib/components/copilot/chat/AIChatManager.svelte'
+import { AttachedFilesStore } from '$lib/components/copilot/chat/files/attachedFiles.svelte'
+import { SessionArtifactsStore } from '$lib/components/copilot/chat/artifacts/artifactsState.svelte'
+
+function toDisplayMessage(
+	message: ChatMessage,
+	userIndex: number,
+	showStepNames: boolean
+): DisplayMessage {
+	switch (message.message_type) {
+		case 'user':
+			return { role: 'user', index: userIndex, content: message.content }
+		case 'tool':
+			// Both producers of a tool row — the agent executor and the frontend's own
+			// stream parser — write the whole message as a one-line description of the
+			// call ("Used web_search tool"). There is no result to reveal, so the row
+			// is the label and nothing else. `toolName` stays unset: it drives the
+			// copilot's plan-card detection, which a flow step summary must not trip.
+			return {
+				role: 'tool',
+				tool_call_id: message.id,
+				content: message.content,
+				isLoading: message.loading
+			}
+		default:
+			return {
+				role: 'assistant',
+				content: message.content,
+				streaming: message.streaming,
+				stepName: showStepNames ? (message.step_name ?? undefined) : undefined
+			}
+	}
+}
+
+/**
+ * Renders a flow run's conversation through the AI session chat components. The
+ * turn itself is a flow job, so everything the copilot's own loop owns — context
+ * elements, attachments, autonomy, model choice — is absent here, and the chrome
+ * driving it hides itself (see ChatViewHost).
+ */
+export class FlowChatViewHost implements ChatViewHost {
+	#manager: FlowChatManager
+	#additionalInputs: () => Record<string, any> | undefined
+
+	constructor(
+		manager: FlowChatManager,
+		additionalInputs: () => Record<string, any> | undefined = () => undefined
+	) {
+		this.#manager = manager
+		this.#additionalInputs = additionalInputs
+	}
+
+	// The step name says which AI agent step wrote a message, so it only tells the
+	// reader anything once a conversation holds more than one. Counted over the
+	// transcript rather than over the flow's current steps: a conversation outlives
+	// edits to the flow, so it can carry labels from a shape the flow no longer has.
+	#showStepNames = $derived.by(
+		() => new Set(this.#manager.messages.map((m) => m.step_name).filter(Boolean)).size > 1
+	)
+
+	displayMessages = $derived.by(() => {
+		let userIndex = 0
+		const showStepNames = this.#showStepNames
+		return this.#manager.messages.map((message) =>
+			toDisplayMessage(message, message.message_type === 'user' ? userIndex++ : -1, showStepNames)
+		)
+	})
+	messages: readonly unknown[] = []
+	contextTokens = 0
+	loading = $derived.by(() => this.#manager.isLoading || this.#manager.isWaitingForResponse)
+	loadingLabel = undefined
+	compacting = false
+	currentReply = ''
+	currentReasoning = ''
+	currentReasoningActive = false
+	reasoningHiddenIndicatorLabel = undefined
+
+	#automaticScroll = $state(true)
+	get automaticScroll() {
+		return this.#automaticScroll
+	}
+	enableAutomaticScroll = () => {
+		this.#automaticScroll = true
+	}
+	disableAutomaticScroll = () => {
+		this.#automaticScroll = false
+	}
+
+	instructions = ''
+	// The flow run is the send: it is in flight for as long as the job is.
+	get sendInFlight() {
+		return this.#manager.isLoading
+	}
+	sendRequest = async (options: ChatSendRequestOptions = {}) => {
+		const text = options.instructions?.trim()
+		if (!text) return false
+		this.#manager.inputMessage = text
+		await this.#manager.sendMessage(this.#additionalInputs())
+		return true
+	}
+	cancel = () => {
+		void this.#manager.cancelCurrentJob()
+	}
+	setAiChatInput = () => {}
+
+	// A message typed while the flow is running waits here and goes out when the
+	// run finishes (see flushQueuedMessage).
+	queuedMessage = $state('')
+	queuedContext = undefined
+	queuedImages = []
+	queuedFiles = []
+	queueMessage = (text: string) => {
+		const trimmed = text.trim()
+		if (!trimmed) return
+		this.queuedMessage = this.queuedMessage ? `${this.queuedMessage}\n${trimmed}` : trimmed
+	}
+	dequeueMessage = () => {
+		this.queuedMessage = ''
+	}
+	/** Send whatever was typed during the run. Called once the run settles. */
+	flushQueuedMessage = () => {
+		const queued = this.queuedMessage
+		if (!queued) return
+		this.queuedMessage = ''
+		void this.sendRequest({ instructions: queued })
+	}
+	setComposerStaged = () => {}
+	clearComposerStaged = () => {}
+	attachmentBytesExcluding = () => 0
+
+	storedImages = () => undefined
+	retryRequest = () => {}
+	restartGeneration = () => {}
+	handleUserQuestionAnswer = () => false
+	handleToolConfirmation = () => {}
+
+	mode = undefined
+	isSessionChat = false
+	supportsModelSettings = false
+	supportsMessageEditing = false
+	tools = []
+	autonomyMode = AIAutonomyMode.DEFAULT
+	setAutonomyMode = () => {}
+	autoAcceptEditsActive = false
+	autoAcceptEditsAvailable = false
+	autoAcceptToolConfirmationsAvailable = false
+	planModeAvailable = false
+	attachedFiles = new AttachedFilesStore()
+	artifacts = new SessionArtifactsStore()
+}

frontend/src/routes/(root)/(logged)/flows/get/[...path]/+page.svelte

@@ -705,6 +705,7 @@
 								path={flow?.path ?? ''}
 								useStreaming={shouldUseStreaming}
 								inputSchema={flow?.schema}
+								wideLayout
 							/>
 						{:else}
 							{@const hasSchema =