webui: auto-refresh /props on inference start to resync model metadata (#16784)

* webui: auto-refresh /props on inference start to resync model metadata

- Add no-cache headers to /props and /slots
- Throttle slot checks to 30s
- Prevent concurrent fetches with promise guard
- Trigger refresh from chat streaming for legacy and ModelSelector
- Show dynamic serverWarning when using cached data

* fix: restore proper legacy behavior in webui by using unified /props refresh

Updated assistant message bubbles to show each message's stored model when available,
falling back to the current server model only when the per-message value is missing

When the model selector is disabled, now fetches /props and prioritizes that model name
over chunk metadata, then persists it with the streamed message so legacy mode properly
reflects the backend configuration

* fix: detect first valid SSE chunk and refresh server props once

* fix: removed the slots availability throttle constant and state

* webui: purge ai-generated cruft

* chore: update webui static build

tools/server/webui/src/lib/components/app/chat/ChatMessages/ChatMessageAssistant.svelte

@@ -85,8 +85,8 @@
 	let displayedModel = $derived((): string | null => {
 		if (!currentConfig.showModelInfo) return null;
 
-		if (currentConfig.modelSelectorEnabled) {
-			return message.model ?? null;
+		if (message.model) {
+			return message.model;
 		}
 
 		return serverModel;

tools/server/webui/src/lib/services/chat.ts

@@ -54,6 +54,7 @@ export class ChatService {
 			onError,
 			onReasoningChunk,
 			onModel,
+			onFirstValidChunk,
 			// Generation parameters
 			temperature,
 			max_tokens,
@@ -201,6 +202,7 @@ export class ChatService {
 					onError,
 					onReasoningChunk,
 					onModel,
+					onFirstValidChunk,
 					conversationId,
 					abortController.signal
 				);
@@ -267,6 +269,7 @@ export class ChatService {
 		onError?: (error: Error) => void,
 		onReasoningChunk?: (chunk: string) => void,
 		onModel?: (model: string) => void,
+		onFirstValidChunk?: () => void,
 		conversationId?: string,
 		abortSignal?: AbortSignal
 	): Promise<void> {
@@ -283,6 +286,7 @@ export class ChatService {
 		let lastTimings: ChatMessageTimings | undefined;
 		let streamFinished = false;
 		let modelEmitted = false;
+		let firstValidChunkEmitted = false;
 
 		try {
 			let chunk = '';
@@ -311,10 +315,12 @@ export class ChatService {
 						try {
 							const parsed: ApiChatCompletionStreamChunk = JSON.parse(data);
 
-							const chunkModel = this.extractModelName(parsed);
-							if (chunkModel && !modelEmitted) {
-								modelEmitted = true;
-								onModel?.(chunkModel);
+							if (!firstValidChunkEmitted && parsed.object === 'chat.completion.chunk') {
+								firstValidChunkEmitted = true;
+
+								if (!abortSignal?.aborted) {
+									onFirstValidChunk?.();
+								}
 							}
 
 							const content = parsed.choices[0]?.delta?.content;
@@ -322,6 +328,12 @@ export class ChatService {
 							const timings = parsed.timings;
 							const promptProgress = parsed.prompt_progress;
 
+							const chunkModel = this.extractModelName(parsed);
+							if (chunkModel && !modelEmitted) {
+								modelEmitted = true;
+								onModel?.(chunkModel);
+							}
+
 							if (timings || promptProgress) {
 								this.updateProcessingState(timings, promptProgress, conversationId);
 								if (timings) {

tools/server/webui/src/lib/stores/chat.svelte.ts

@@ -1,6 +1,7 @@
 import { DatabaseStore } from '$lib/stores/database';
 import { chatService, slotsService } from '$lib/services';
 import { config } from '$lib/stores/settings.svelte';
+import { serverStore } from '$lib/stores/server.svelte';
 import { normalizeModelName } from '$lib/utils/model-names';
 import { filterByLeafNodeId, findLeafNode, findDescendantMessages } from '$lib/utils/branching';
 import { browser } from '$app/environment';
@@ -362,9 +363,41 @@ class ChatStore {
 
 		let resolvedModel: string | null = null;
 		let modelPersisted = false;
+		const currentConfig = config();
+		const preferServerPropsModel = !currentConfig.modelSelectorEnabled;
+		let serverPropsRefreshed = false;
+		let updateModelFromServerProps: ((persistImmediately?: boolean) => void) | null = null;
 
-		const recordModel = (modelName: string, persistImmediately = true): void => {
-			const normalizedModel = normalizeModelName(modelName);
+		const refreshServerPropsOnce = () => {
+			if (serverPropsRefreshed) {
+				return;
+			}
+
+			serverPropsRefreshed = true;
+
+			const hasExistingProps = serverStore.serverProps !== null;
+
+			serverStore
+				.fetchServerProps({ silent: hasExistingProps })
+				.then(() => {
+					updateModelFromServerProps?.(true);
+				})
+				.catch((error) => {
+					console.warn('Failed to refresh server props after streaming started:', error);
+				});
+		};
+
+		const recordModel = (modelName: string | null | undefined, persistImmediately = true): void => {
+			const serverModelName = serverStore.modelName;
+			const preferredModelSource = preferServerPropsModel
+				? (serverModelName ?? modelName ?? null)
+				: (modelName ?? serverModelName ?? null);
+
+			if (!preferredModelSource) {
+				return;
+			}
+
+			const normalizedModel = normalizeModelName(preferredModelSource);
 
 			if (!normalizedModel || normalizedModel === resolvedModel) {
 				return;
@@ -388,6 +421,20 @@ class ChatStore {
 			}
 		};
 
+		if (preferServerPropsModel) {
+			updateModelFromServerProps = (persistImmediately = true) => {
+				const currentServerModel = serverStore.modelName;
+
+				if (!currentServerModel) {
+					return;
+				}
+
+				recordModel(currentServerModel, persistImmediately);
+			};
+
+			updateModelFromServerProps(false);
+		}
+
 		slotsService.startStreaming();
 		slotsService.setActiveConversation(assistantMessage.convId);
 
@@ -396,6 +443,9 @@ class ChatStore {
 			{
 				...this.getApiOptions(),
 
+				onFirstValidChunk: () => {
+					refreshServerPropsOnce();
+				},
 				onChunk: (chunk: string) => {
 					streamedContent += chunk;
 					this.setConversationStreaming(

tools/server/webui/src/lib/stores/server.svelte.ts

@@ -52,6 +52,7 @@ class ServerStore {
 	private _error = $state<string | null>(null);
 	private _serverWarning = $state<string | null>(null);
 	private _slotsEndpointAvailable = $state<boolean | null>(null);
+	private fetchServerPropsPromise: Promise<void> | null = null;
 
 	private readCachedServerProps(): ApiLlamaCppServerProps | null {
 		if (!browser) return null;
@@ -171,73 +172,65 @@ class ServerStore {
 	/**
 	 * Fetches server properties from the server
 	 */
-	async fetchServerProps(): Promise<void> {
-		this._loading = true;
-		this._error = null;
-		this._serverWarning = null;
+	async fetchServerProps(options: { silent?: boolean } = {}): Promise<void> {
+		const { silent = false } = options;
+		const isSilent = silent && this._serverProps !== null;
 
-		try {
-			console.log('Fetching server properties...');
-			const props = await ChatService.getServerProps();
-			this._serverProps = props;
-			this.persistServerProps(props);
-			console.log('Server properties loaded:', props);
+		if (this.fetchServerPropsPromise) {
+			return this.fetchServerPropsPromise;
+		}
 
-			// Check slots endpoint availability after server props are loaded
-			await this.checkSlotsEndpointAvailability();
-		} catch (error) {
-			const hadCachedProps = this._serverProps !== null;
-			let errorMessage = 'Failed to connect to server';
-			let isOfflineLikeError = false;
-			let isServerSideError = false;
+		if (!isSilent) {
+			this._loading = true;
+			this._error = null;
+			this._serverWarning = null;
+		}
 
-			if (error instanceof Error) {
-				// Handle specific error types with user-friendly messages
-				if (error.name === 'TypeError' && error.message.includes('fetch')) {
-					errorMessage = 'Server is not running or unreachable';
-					isOfflineLikeError = true;
-				} else if (error.message.includes('ECONNREFUSED')) {
-					errorMessage = 'Connection refused - server may be offline';
-					isOfflineLikeError = true;
-				} else if (error.message.includes('ENOTFOUND')) {
-					errorMessage = 'Server not found - check server address';
-					isOfflineLikeError = true;
-				} else if (error.message.includes('ETIMEDOUT')) {
-					errorMessage = 'Request timed out - the server took too long to respond';
-					isOfflineLikeError = true;
-				} else if (error.message.includes('503')) {
-					errorMessage = 'Server temporarily unavailable - try again shortly';
-					isServerSideError = true;
-				} else if (error.message.includes('500')) {
-					errorMessage = 'Server error - check server logs';
-					isServerSideError = true;
-				} else if (error.message.includes('404')) {
-					errorMessage = 'Server endpoint not found';
-				} else if (error.message.includes('403') || error.message.includes('401')) {
-					errorMessage = 'Access denied';
+		const hadProps = this._serverProps !== null;
+
+		const fetchPromise = (async () => {
+			try {
+				const props = await ChatService.getServerProps();
+				this._serverProps = props;
+				this.persistServerProps(props);
+				this._error = null;
+				this._serverWarning = null;
+				await this.checkSlotsEndpointAvailability();
+			} catch (error) {
+				if (isSilent && hadProps) {
+					console.warn('Silent server props refresh failed, keeping cached data:', error);
+					return;
 				}
+
+				this.handleFetchServerPropsError(error, hadProps);
+			} finally {
+				if (!isSilent) {
+					this._loading = false;
+				}
+
+				this.fetchServerPropsPromise = null;
 			}
+		})();
 
-			let cachedProps: ApiLlamaCppServerProps | null = null;
+		this.fetchServerPropsPromise = fetchPromise;
 
-			if (!hadCachedProps) {
-				cachedProps = this.readCachedServerProps();
-				if (cachedProps) {
-					this._serverProps = cachedProps;
-					this._error = null;
+		await fetchPromise;
+	}
 
-					if (isOfflineLikeError || isServerSideError) {
-						this._serverWarning = errorMessage;
-					}
+	/**
+	 * Handles fetch failures by attempting to recover cached server props and
+	 * updating the user-facing error or warning state appropriately.
+	 */
+	private handleFetchServerPropsError(error: unknown, hadProps: boolean): void {
+		const { errorMessage, isOfflineLikeError, isServerSideError } = this.normalizeFetchError(error);
 
-					console.warn(
-						'Failed to refresh server properties, using cached values from localStorage:',
-						errorMessage
-					);
-				} else {
-					this._error = errorMessage;
-				}
-			} else {
+		let cachedProps: ApiLlamaCppServerProps | null = null;
+
+		if (!hadProps) {
+			cachedProps = this.readCachedServerProps();
+
+			if (cachedProps) {
+				this._serverProps = cachedProps;
 				this._error = null;
 
 				if (isOfflineLikeError || isServerSideError) {
@@ -245,14 +238,66 @@ class ServerStore {
 				}
 
 				console.warn(
-					'Failed to refresh server properties, continuing with cached values:',
+					'Failed to refresh server properties, using cached values from localStorage:',
 					errorMessage
 				);
+			} else {
+				this._error = errorMessage;
 			}
-			console.error('Error fetching server properties:', error);
-		} finally {
-			this._loading = false;
+		} else {
+			this._error = null;
+
+			if (isOfflineLikeError || isServerSideError) {
+				this._serverWarning = errorMessage;
+			}
+
+			console.warn(
+				'Failed to refresh server properties, continuing with cached values:',
+				errorMessage
+			);
 		}
+
+		console.error('Error fetching server properties:', error);
+	}
+
+	private normalizeFetchError(error: unknown): {
+		errorMessage: string;
+		isOfflineLikeError: boolean;
+		isServerSideError: boolean;
+	} {
+		let errorMessage = 'Failed to connect to server';
+		let isOfflineLikeError = false;
+		let isServerSideError = false;
+
+		if (error instanceof Error) {
+			const message = error.message || '';
+
+			if (error.name === 'TypeError' && message.includes('fetch')) {
+				errorMessage = 'Server is not running or unreachable';
+				isOfflineLikeError = true;
+			} else if (message.includes('ECONNREFUSED')) {
+				errorMessage = 'Connection refused - server may be offline';
+				isOfflineLikeError = true;
+			} else if (message.includes('ENOTFOUND')) {
+				errorMessage = 'Server not found - check server address';
+				isOfflineLikeError = true;
+			} else if (message.includes('ETIMEDOUT')) {
+				errorMessage = 'Request timed out - the server took too long to respond';
+				isOfflineLikeError = true;
+			} else if (message.includes('503')) {
+				errorMessage = 'Server temporarily unavailable - try again shortly';
+				isServerSideError = true;
+			} else if (message.includes('500')) {
+				errorMessage = 'Server error - check server logs';
+				isServerSideError = true;
+			} else if (message.includes('404')) {
+				errorMessage = 'Server endpoint not found';
+			} else if (message.includes('403') || message.includes('401')) {
+				errorMessage = 'Access denied';
+			}
+		}
+
+		return { errorMessage, isOfflineLikeError, isServerSideError };
 	}
 
 	/**
@@ -264,6 +309,7 @@ class ServerStore {
 		this._serverWarning = null;
 		this._loading = false;
 		this._slotsEndpointAvailable = null;
+		this.fetchServerPropsPromise = null;
 		this.persistServerProps(null);
 	}
 }

tools/server/webui/src/lib/types/api.d.ts

@@ -186,6 +186,7 @@ export interface ApiChatCompletionRequest {
 }
 
 export interface ApiChatCompletionStreamChunk {
+	object?: string;
 	model?: string;
 	choices: Array<{
 		model?: string;

tools/server/webui/src/lib/types/settings.d.ts

@@ -42,6 +42,7 @@ export interface SettingsChatServiceOptions {
 	onChunk?: (chunk: string) => void;
 	onReasoningChunk?: (chunk: string) => void;
 	onModel?: (model: string) => void;
+	onFirstValidChunk?: () => void;
 	onComplete?: (response: string, reasoningContent?: string, timings?: ChatMessageTimings) => void;
 	onError?: (error: Error) => void;
 }