refac

backend/open_webui/main.py

@@ -220,6 +220,9 @@ from open_webui.utils.chat import (
 from open_webui.utils.chat import (
     generate_chat_completion as chat_completion_handler,
 )
+from open_webui.utils.chat_variables import (
+    normalize_chat_variables,
+)
 from open_webui.utils.embeddings import generate_embeddings
 from open_webui.utils.logger import start_logger
 from open_webui.utils.middleware import (
@@ -1135,6 +1138,13 @@ async def chat_completion(
             message_ids = [{'model_id': model_id, 'message_id': form_data.pop('id', None)}]
 
         user_message = form_data.pop('user_message', None) or form_data.pop('parent_message', None)
+        chat_id = form_data.get('chat_id') or ''
+        chat_variables = form_data.pop('chat_variables', None)
+        if chat_variables is None:
+            existing_chat = await Chats.get_chat_by_id(chat_id) if chat_id else None
+            chat_variables = existing_chat.variables if existing_chat else {}
+
+        chat_variables = normalize_chat_variables(chat_variables)
 
         # Drop tool_servers if caller lacks features.direct_tool_servers —
         # mirrors the storage-side strip in user/settings/update.
@@ -1166,6 +1176,7 @@ async def chat_completion(
             'files': form_data.get('files', None),
             'features': form_data.get('features', {}),
             'variables': form_data.get('variables', {}),
+            'chat_variables': chat_variables,
             'model': model,
             'direct': model_item.get('direct', False),
             'params': {
@@ -1280,6 +1291,7 @@ async def chat_completion(
                                 'tags': [],
                                 'timestamp': int(time.time() * 1000),
                             },
+                            variables=chat_variables,
                             folder_id=metadata.get('folder_id'),
                         ),
                     )
@@ -1385,6 +1397,8 @@ async def chat_completion(
                                 updated['models'] = selected_chat_models
                             await Chats.update_chat_by_id(chat_id, updated)
 
+                    await Chats.update_chat_variables_by_id(chat_id, chat_variables)
+
                     # Save user message to DB
                     if user_message and user_message.get('id'):
                         await Chats.upsert_message_to_chat_by_id_and_message_id(

backend/open_webui/routers/models.py

@@ -40,6 +40,7 @@ from open_webui.models.models import (
 from open_webui.utils.access_control import filter_allowed_access_grants, has_permission
 from open_webui.utils.access_control.files import has_access_to_file
 from open_webui.utils.auth import get_admin_user, get_verified_user
+from open_webui.utils.chat_variables import get_chat_variables_schema
 from pydantic import BaseModel
 from sqlalchemy.ext.asyncio import AsyncSession
 
@@ -48,6 +49,14 @@ log = logging.getLogger(__name__)
 router = APIRouter()
 
 
+def add_chat_variables_schema(model_dict: dict) -> dict:
+    system = ((model_dict.get('params') or {}).get('system') if isinstance(model_dict.get('params'), dict) else None)
+    schema = get_chat_variables_schema(system)
+    if schema:
+        model_dict.setdefault('meta', {})['chat_variables_schema'] = schema
+    return model_dict
+
+
 def _safe_static_redirect_path(url: str) -> str | None:
     """
     If url is a same-origin static asset path, return a normalized path safe for
@@ -177,7 +186,7 @@ async def get_models(
     # Strip profile_image_url from meta — images are served via /model/profile/image.
     items = []
     for model in result.items:
-        data = model.model_dump()
+        data = add_chat_variables_schema(model.model_dump())
         if data.get('meta'):
             data['meta'].pop('profile_image_url', None)
         items.append(
@@ -527,6 +536,7 @@ async def get_model_by_id(id: str, user=Depends(get_verified_user), db: AsyncSes
             db=db,
         ):
             model_dict = model.model_dump()
+            model_dict = add_chat_variables_schema(model_dict)
             # Strip params (system prompt and other admin-curated config)
             # for read-only callers — matches the params strip already
             # enforced on /api/models in utils/models.py.  Owners, admins

backend/open_webui/utils/chat_variables.py

@@ -0,0 +1,242 @@
+from __future__ import annotations
+
+import json
+import re
+from typing import Any
+
+
+CHAT_VARIABLE_KEY_RE = re.compile(r'^[a-z][a-z0-9_]*$')
+CHAT_VARIABLE_ANY_RE = re.compile(r'{{\s*chat\.variables\.([^\s|}]+)(?:\s*\|\s*([^}]*))?\s*}}')
+MAX_VARIABLE_VALUE_LENGTH = 20_000
+MAX_VARIABLES_JSON_LENGTH = 100_000
+
+
+class ChatVariablesError(ValueError):
+    pass
+
+
+def split_properties(value: str, delimiter: str) -> list[str]:
+    result: list[str] = []
+    current = ''
+    depth = 0
+    in_string = False
+    escape_next = False
+
+    for char in value:
+        if escape_next:
+            current += char
+            escape_next = False
+            continue
+
+        if char == '\\':
+            current += char
+            escape_next = True
+            continue
+
+        if char == '"' and not escape_next:
+            in_string = not in_string
+            current += char
+            continue
+
+        if not in_string:
+            if char in ('{', '['):
+                depth += 1
+            elif char in ('}', ']'):
+                depth -= 1
+
+            if char == delimiter and depth == 0:
+                result.append(current.strip())
+                current = ''
+                continue
+
+        current += char
+
+    if current.strip():
+        result.append(current.strip())
+
+    return result
+
+
+def parse_json_value(value: str) -> Any:
+    if value.startswith('"') and value.endswith('"'):
+        return value[1:-1]
+
+    if re.match(r'^[\[{]', value):
+        try:
+            return json.loads(value)
+        except json.JSONDecodeError:
+            return value
+
+    return value
+
+
+def parse_variable_definition(definition: str) -> dict[str, Any]:
+    parts = split_properties(definition, ':')
+    if not parts:
+        return {'type': 'text'}
+
+    first_part, *property_parts = parts
+    field_type = first_part[5:] if first_part.startswith('type=') else first_part
+    field_type = field_type.strip() or 'text'
+    properties: dict[str, Any] = {}
+
+    for part in property_parts:
+        trimmed = part.strip()
+        if not trimmed:
+            continue
+
+        equals_parts = split_properties(trimmed, '=')
+        if len(equals_parts) == 1:
+            properties[equals_parts[0].strip()] = True
+            continue
+
+        property_name, *value_parts = equals_parts
+        properties[property_name.strip()] = parse_json_value('='.join(value_parts).strip())
+
+    return {'type': field_type, **properties}
+
+
+def _safe_field(key: str, definition: dict[str, Any]) -> dict[str, Any]:
+    allowed_keys = {
+        'default',
+        'label',
+        'max',
+        'maxlength',
+        'min',
+        'minlength',
+        'options',
+        'placeholder',
+        'required',
+        'step',
+        'type',
+    }
+    field = {'key': key}
+    for field_key in allowed_keys:
+        if field_key in definition:
+            field[field_key] = definition[field_key]
+
+    field.setdefault('type', 'text')
+    if field.get('type') == 'select' and not isinstance(field.get('options'), list):
+        field['options'] = []
+    field['required'] = bool(field.get('required', False))
+
+    return field
+
+
+def get_chat_variables_schema(system_prompt: str | None) -> dict[str, list[dict[str, Any]]] | None:
+    if not system_prompt:
+        return None
+
+    try:
+        fields_by_key = collect_chat_variable_fields(system_prompt)
+    except ChatVariablesError:
+        fields_by_key = {}
+
+    if not fields_by_key:
+        return None
+
+    return {'fields': list(fields_by_key.values())}
+
+
+def collect_chat_variable_fields(system_prompt: str | None) -> dict[str, dict[str, Any]]:
+    fields_by_key: dict[str, dict[str, Any]] = {}
+    if not system_prompt:
+        return fields_by_key
+
+    typed_fields_by_key: dict[str, dict[str, Any]] = {}
+    for match in CHAT_VARIABLE_ANY_RE.finditer(system_prompt):
+        key = match.group(1).strip()
+        definition = match.group(2)
+        if not CHAT_VARIABLE_KEY_RE.match(key):
+            raise ChatVariablesError(f'Invalid chat variable key: {key}')
+
+        if definition is None or not definition.strip():
+            fields_by_key.setdefault(key, _safe_field(key, {'type': 'text'}))
+            continue
+
+        field = _safe_field(key, parse_variable_definition(definition.strip()))
+
+        if field.get('type') == 'select' and not field.get('options'):
+            raise ChatVariablesError(f'Chat variable {key} select needs options.')
+        previous = typed_fields_by_key.get(key)
+        if previous and previous != field:
+            raise ChatVariablesError(f'Chat variable {key} has conflicting definitions.')
+        typed_fields_by_key[key] = field
+        fields_by_key[key] = field
+
+    return fields_by_key
+
+
+def normalize_chat_variables(variables: Any) -> dict[str, Any]:
+    if not isinstance(variables, dict):
+        return {}
+    return variables
+
+
+def validate_chat_variables(
+    system_prompt: str | None,
+    variables: Any,
+    *,
+    required: bool = True,
+) -> dict[str, Any]:
+    field_map = collect_chat_variable_fields(system_prompt)
+    variables = normalize_chat_variables(variables)
+
+    try:
+        if len(json.dumps(variables)) > MAX_VARIABLES_JSON_LENGTH:
+            raise ChatVariablesError('Chat variables are too large.')
+    except TypeError:
+        raise ChatVariablesError('Chat variables must be JSON serializable.')
+
+    validated: dict[str, Any] = {}
+    for key, field in field_map.items():
+        has_value = key in variables and variables[key] not in (None, '')
+        value = variables.get(key)
+
+        if not has_value:
+            if field.get('default') not in (None, ''):
+                value = field.get('default')
+                has_value = True
+            elif required and field.get('required'):
+                label = field.get('label') or key
+                raise ChatVariablesError(f'Missing required chat variable: {label}')
+            else:
+                value = ''
+
+        if field.get('type') == 'select':
+            options = field.get('options') or []
+            if has_value and value not in options:
+                label = field.get('label') or key
+                raise ChatVariablesError(f'Invalid value for chat variable: {label}')
+
+        if isinstance(value, str):
+            value = value.replace('\r\n', '\n')
+            if len(value) > MAX_VARIABLE_VALUE_LENGTH:
+                label = field.get('label') or key
+                raise ChatVariablesError(f'Chat variable is too long: {label}')
+
+        validated[key] = value
+
+    return validated
+
+
+def render_chat_variables(
+    system_prompt: str | None,
+    variables: Any,
+    *,
+    required: bool = True,
+) -> str | None:
+    if not system_prompt:
+        return system_prompt
+
+    try:
+        validated = validate_chat_variables(system_prompt, variables, required=required)
+    except ChatVariablesError:
+        validated = {}
+
+    def replace(match: re.Match) -> str:
+        key = match.group(1).strip()
+        value = validated.get(key, '')
+        return '' if value is None else str(value)
+
+    return CHAT_VARIABLE_ANY_RE.sub(replace, system_prompt)

backend/open_webui/utils/models.py

@@ -16,6 +16,7 @@ from open_webui.models.config import Config
 from open_webui.models.functions import Functions
 from open_webui.models.groups import Groups
 from open_webui.models.models import Models
+from open_webui.utils.chat_variables import get_chat_variables_schema
 from open_webui.models.users import UserModel
 from open_webui.routers import ollama, openai
 from open_webui.socket.utils import RedisDict
@@ -162,6 +163,9 @@ async def get_all_models(request, refresh: bool = False, user: UserModel = None)
                 if custom_model.is_active:
                     model['name'] = custom_model.name
                     model['info'] = custom_model.model_dump()
+                    schema = get_chat_variables_schema(custom_model.params.model_dump().get('system'))
+                    if schema:
+                        model['info'].setdefault('meta', {})['chat_variables_schema'] = schema
 
                     action_ids = []
                     filter_ids = []
@@ -211,6 +215,9 @@ async def get_all_models(request, refresh: bool = False, user: UserModel = None)
             }
 
             info = custom_model.model_dump()
+            schema = get_chat_variables_schema(custom_model.params.model_dump().get('system'))
+            if schema:
+                info.setdefault('meta', {})['chat_variables_schema'] = schema
             if 'params' in info:
                 # Remove params to avoid exposing sensitive info
                 del info['params']

backend/open_webui/utils/payload.py

@@ -7,6 +7,7 @@ from open_webui.utils.misc import (
     deep_update,
     replace_system_message_content,
 )
+from open_webui.utils.chat_variables import render_chat_variables
 from open_webui.utils.task import prompt_template, prompt_variables_template
 
 
@@ -18,6 +19,13 @@ async def resolve_system_prompt(
     if not system:
         return ''
 
+    if metadata:
+        system = render_chat_variables(
+            system,
+            metadata.get('chat_variables', {}),
+            required=False,
+        )
+
     # Metadata (WebUI Usage)
     if metadata:
         variables = metadata.get('variables', {})

src/lib/apis/chats/index.ts

@@ -58,7 +58,12 @@ export const updateChatConfig = async (token: string, config: object) => {
 	return res;
 };
 
-export const createNewChat = async (token: string, chat: object, folderId: string | null) => {
+export const createNewChat = async (
+	token: string,
+	chat: object,
+	folderId: string | null,
+	variables: object | null = null
+) => {
 	let error = null;
 
 	const res = await fetch(`${WEBUI_API_BASE_URL}/chats/new`, {
@@ -70,6 +75,7 @@ export const createNewChat = async (token: string, chat: object, folderId: strin
 		},
 		body: JSON.stringify({
 			chat: chat,
+			...(variables !== null ? { variables } : {}),
 			folder_id: folderId ?? null
 		})
 	})
@@ -1197,7 +1203,12 @@ export const getChatAccessGrants = async (token: string, id: string) => {
 	return res;
 };
 
-export const updateChatById = async (token: string, id: string, chat: object) => {
+export const updateChatById = async (
+	token: string,
+	id: string,
+	chat: object,
+	variables: object | null = null
+) => {
 	let error = null;
 
 	const res = await fetch(`${WEBUI_API_BASE_URL}/chats/${id}`, {
@@ -1208,7 +1219,8 @@ export const updateChatById = async (token: string, id: string, chat: object) =>
 			...(token && { authorization: `Bearer ${token}` })
 		},
 		body: JSON.stringify({
-			chat: chat
+			chat: chat,
+			...(variables !== null ? { variables } : {})
 		})
 	})
 		.then(async (res) => {

src/lib/apis/index.ts

@@ -163,7 +163,14 @@ export const getModels = async (
 		// Remove duplicates
 		const modelsMap = {};
 		for (const model of models) {
-			modelsMap[model.id] = model;
+			const existing = modelsMap[model.id];
+			modelsMap[model.id] = existing
+				? {
+						...existing,
+						...model,
+						info: existing.info ?? model.info
+					}
+				: model;
 		}
 
 		models = Object.values(modelsMap);

src/lib/components/chat/Chat.svelte

@@ -111,12 +111,14 @@
 	import FilesOverlay from './MessageInput/FilesOverlay.svelte';
 	import NotificationToast from '../NotificationToast.svelte';
 	import Spinner from '../common/Spinner.svelte';
+	import Modal from '../common/Modal.svelte';
 	import { isEmbedWindow } from '../common/FullHeightIframe.svelte';
 	import Tooltip from '../common/Tooltip.svelte';
 	import Sidebar from '../icons/Sidebar.svelte';
 	import Image from '../common/Image.svelte';
 	import XMark from '../icons/XMark.svelte';
 	import EmbeddedChatHistoryDropdown from './EmbeddedChatHistoryDropdown.svelte';
+	import InputVariablesModal from './MessageInput/InputVariablesModal.svelte';
 
 	export let chatIdProp = '';
 	export let embedded = false;
@@ -367,9 +369,112 @@
 	let chatFiles = [];
 	let files = [];
 	let params = {};
+	let chatVariables = {};
+	let showChatVariablesModal = false;
 	let loadedChatIdProp = '';
 	let currentDraftKey = '';
 
+	const mergeChatVariableSchemas = (modelIds = []) => {
+		const byKey: Record<string, any> = {};
+		const conflicts: any[] = [];
+
+		for (const modelId of modelIds.filter(Boolean)) {
+			const fields =
+				$models.find((model) => model.id === modelId)?.info?.meta?.chat_variables_schema?.fields ??
+				[];
+			for (const rawField of fields) {
+				const field = {
+					...rawField,
+					type: rawField?.type ?? 'text',
+					required: Boolean(rawField?.required)
+				};
+				if (!field?.key) continue;
+				const { required, ...shape } = field;
+
+				const existing = byKey[field.key];
+				if (!existing) {
+					byKey[field.key] = {
+						field,
+						modelIds: [modelId],
+						shape
+					};
+					continue;
+				}
+
+				if (!equal(existing.shape, shape)) {
+					conflicts.push({
+						key: field.key,
+						modelIds: [...existing.modelIds, modelId]
+					});
+					continue;
+				}
+
+				existing.field = {
+					...existing.field,
+					required: existing.field.required || field.required
+				};
+				existing.modelIds.push(modelId);
+			}
+		}
+
+		return {
+			fields: Object.values(byKey).map((item: any) => item.field),
+			conflicts
+		};
+	};
+
+	const hasValue = (value) => value !== undefined && value !== null && value !== '';
+
+	const getChatVariablesForm = () => {
+		const { fields, conflicts } = mergeChatVariableSchemas(selectedModelIds);
+		const empty =
+			fields.length > 0 &&
+			fields.every((field) => !hasValue(chatVariables?.[field.key]) && !hasValue(field.default));
+		const missing = fields.some(
+			(field) => field.required && !hasValue(chatVariables?.[field.key]) && !hasValue(field.default)
+		);
+		const variables = fields.reduce(
+			(acc, field) => {
+				const { key, ...inputField } = field;
+				acc[key] = {
+					...inputField,
+					default: hasValue(chatVariables?.[key]) ? chatVariables[key] : inputField.default
+				};
+				return acc;
+			},
+			{} as Record<string, any>
+		);
+
+		return { conflicts, empty, missing, variables };
+	};
+
+	const saveChatVariables = async (values) => {
+		chatVariables = { ...chatVariables, ...values };
+
+		if ($chatId && !$temporaryChatEnabled && !$chatId.startsWith('local:')) {
+			const res = await updateChatById(localStorage.token, $chatId, {}, chatVariables).catch(
+				(err) => {
+					console.error('[chat variables save]', err);
+					toast.error($i18n.t('Failed to save chat variables'));
+					return null;
+				}
+			);
+			if (res) chat = res;
+		}
+	};
+
+	$: chatVariablesForm = getChatVariablesForm();
+
+	let oldSelectedModelIds = [''];
+	$: if (!equal(selectedModelIds, oldSelectedModelIds)) {
+		onSelectedModelIdsChange();
+	}
+
+	const onSelectedModelIdsChange = () => {
+		resetInput();
+		oldSelectedModelIds = structuredClone(selectedModelIds);
+	};
+
 	const mergeFiles = (current, incoming) => {
 		const seen = new Set();
 		return [...(incoming ?? []), ...(current ?? [])].filter((file) => {
@@ -514,6 +619,7 @@
 			currentId: null
 		};
 		params = {};
+		chatVariables = {};
 		chatFiles = [];
 		files = [];
 		selectedToolIds = [];
@@ -585,16 +691,6 @@
 		initiateOAuthRedirect(nextTool);
 	};
 
-	let oldSelectedModelIds = [''];
-	$: if (!equal(selectedModelIds, oldSelectedModelIds)) {
-		onSelectedModelIdsChange();
-	}
-
-	const onSelectedModelIdsChange = () => {
-		resetInput();
-		oldSelectedModelIds = structuredClone(selectedModelIds);
-	};
-
 	const resetInput = async () => {
 		selectedToolIds = [];
 		selectedSkillIds = [];
@@ -1703,6 +1799,7 @@
 
 		chatFiles = [];
 		params = {};
+		chatVariables = {};
 		taskIds = null;
 		chatTasks = [];
 
@@ -1854,6 +1951,7 @@
 			noteChatDebug('getTagsById completed', { tagCount: tags?.length ?? 0 });
 
 			const chatContent = chat.chat;
+			chatVariables = chat?.variables ?? {};
 
 			if (chatContent) {
 				noteChatDebug('chat payload found', {
@@ -2552,6 +2650,15 @@
 			toast.error($i18n.t('Model not selected'));
 			return;
 		}
+		if (chatVariablesForm.conflicts.length > 0) {
+			showChatVariablesModal = true;
+			toast.error($i18n.t('Chat Variables have conflicting model definitions'));
+			return;
+		}
+		if (chatVariablesForm.missing || chatVariablesForm.empty) {
+			showChatVariablesModal = true;
+			return;
+		}
 
 		if (
 			files.length > 0 &&
@@ -2968,6 +3075,8 @@
 
 		// Only send terminal_id if the model has terminal capability enabled
 		const terminalEnabled = model.info?.meta?.capabilities?.terminal ?? true;
+		const useChatVariablesFallback =
+			!_chatId || $temporaryChatEnabled || _chatId.startsWith('local:');
 
 		const res = await generateOpenAIChatCompletion(
 			localStorage.token,
@@ -3002,6 +3111,7 @@
 						$user?.email
 					)
 				},
+				...(useChatVariablesFallback ? { chat_variables: chatVariables } : {}),
 				model_item: $models.find((m) => m.id === model.id),
 
 				session_id: $socket?.id,
@@ -3352,7 +3462,8 @@
 					tags: [],
 					timestamp: Date.now()
 				},
-				$selectedFolder?.id
+				$selectedFolder?.id,
+				chatVariables
 			);
 
 			_chatId = chat.id;
@@ -3515,6 +3626,47 @@
 
 <audio id="audioElement" style="display: none;"></audio>
 
+{#if chatVariablesForm.conflicts.length > 0}
+	<Modal bind:show={showChatVariablesModal} size="md">
+		<div>
+			<div class="flex justify-between px-4 pt-3 pb-1 dark:text-gray-300">
+				<div class="self-center text-sm font-medium">{$i18n.t('Chat Variables')}</div>
+				<button
+					class="self-center rounded-lg p-1 text-gray-500 transition hover:bg-gray-50 hover:text-gray-700 dark:text-gray-400 dark:hover:bg-gray-800 dark:hover:text-gray-200"
+					on:click={() => {
+						showChatVariablesModal = false;
+					}}
+				>
+					<XMark className="size-4" />
+				</button>
+			</div>
+
+			<div class="px-5 pb-4 text-sm text-gray-600 dark:text-gray-300">
+				<div class="mb-2 text-xs text-gray-500 dark:text-gray-400">
+					{$i18n.t('Selected models define incompatible Chat Variables.')}
+				</div>
+				<div class="flex flex-col gap-1">
+					{#each chatVariablesForm.conflicts as conflict}
+						<div class="rounded-lg border border-red-200 px-3 py-2 text-xs dark:border-red-900/60">
+							<div class="font-medium text-red-600 dark:text-red-400">{conflict.key}</div>
+							<div class="mt-1 text-gray-500 dark:text-gray-400">
+								{conflict.modelIds.join(', ')}
+							</div>
+						</div>
+					{/each}
+				</div>
+			</div>
+		</div>
+	</Modal>
+{:else}
+	<InputVariablesModal
+		bind:show={showChatVariablesModal}
+		title={$i18n.t('Chat Variables')}
+		variables={chatVariablesForm.variables}
+		onSave={saveChatVariables}
+	/>
+{/if}
+
 <WebSearchConfirmDialog
 	bind:show={showWebSearchConfirm}
 	title={$i18n.t('Use Web Search?')}
@@ -3673,7 +3825,8 @@
 											messages: messages,
 											timestamp: Date.now()
 										},
-										null
+										null,
+										chatVariables
 									);
 
 									if (savedChat) {
@@ -3819,6 +3972,9 @@
 											}
 										}}
 										onWebSearchToggle={handleWebSearchToggle}
+										on:chatVariables={() => {
+											showChatVariablesModal = true;
+										}}
 										on:submit={async (e) => {
 											clearDraft($chatId);
 											if (e.detail || files.length > 0) {
@@ -3895,6 +4051,9 @@
 										messageQueue={$chatRequestQueues[$chatId] ?? []}
 										{chatTasks}
 										onWebSearchToggle={handleWebSearchToggle}
+										on:chatVariables={() => {
+											showChatVariablesModal = true;
+										}}
 										on:submit={async (e) => {
 											clearDraft($chatId);
 											if (e.detail || files.length > 0) {
@@ -3930,6 +4089,9 @@
 									{onSelect}
 									{onUpload}
 									onWebSearchToggle={handleWebSearchToggle}
+									on:chatVariables={() => {
+										showChatVariablesModal = true;
+									}}
 									onChange={(data) => {
 										if (!$temporaryChatEnabled) {
 											saveDraft(data);

src/lib/components/chat/MessageInput.svelte

@@ -132,6 +132,11 @@
 
 	let selectedModelIds = [];
 	$: selectedModelIds = atSelectedModel !== undefined ? [atSelectedModel.id] : selectedModels;
+	$: hasChatVariables = selectedModelIds.some(
+		(modelId) =>
+			($models.find((model) => model.id === modelId)?.info?.meta?.chat_variables_schema?.fields
+				?.length ?? 0) > 0
+	);
 
 	export let history;
 	export let taskIds = null;
@@ -2236,6 +2241,22 @@
 										/>
 									</div>
 
+									{#if hasChatVariables}
+										<Tooltip content={$i18n.t('Chat Variables')} placement="top">
+											<button
+												type="button"
+												id="chat-variables-button"
+												class="flex size-[1.875rem] shrink-0 items-center justify-center rounded-full bg-transparent text-gray-500 transition-colors hover:text-gray-800 focus:outline-hidden dark:text-gray-400 dark:hover:text-gray-100"
+												aria-label={$i18n.t('Chat Variables')}
+												on:click={() => {
+													dispatch('chatVariables');
+												}}
+											>
+												<Knobs className="size-4" strokeWidth="1.5" />
+											</button>
+										</Tooltip>
+									{/if}
+
 									{#if isActive && prompt === '' && files.length === 0}
 										<div class=" flex items-center">
 											<Tooltip content={$i18n.t('Stop')}>

src/lib/components/chat/Placeholder.svelte

@@ -237,6 +237,7 @@
 						{onChange}
 						{onUpload}
 						{onWebSearchToggle}
+						on:chatVariables
 						on:submit={(e) => {
 							dispatch('submit', e.detail);
 						}}

src/lib/components/workspace/Models/ModelEditor.svelte

@@ -33,6 +33,7 @@
 	import TTSVoiceInput from './TTSVoiceInput.svelte';
 	import AccessControlModal from '../common/AccessControlModal.svelte';
 	import AccessButton from '$lib/components/common/AccessButton.svelte';
+	import { extractInputVariables } from '$lib/utils';
 
 	const i18n = getContext('i18n');
 
@@ -113,6 +114,46 @@
 	export let suggestionTags: { name: string }[] = [];
 	let voices: { id: string; name?: string }[] = [];
 
+	const chatVariableKeyRegex = /^[a-z][a-z0-9_]*$/;
+	const getChatVariablesPreview = (prompt: string) => {
+		const variables = extractInputVariables(prompt);
+		const warnings: string[] = [];
+		const seenDefinitions: Record<string, string> = {};
+		const typedRegex = /{{\s*chat\.variables\.([a-zA-Z0-9_.-]+)\s*\|\s*([^}]*)\s*}}/g;
+
+		for (const match of prompt.matchAll(typedRegex)) {
+			const key = match[1];
+			const definition = match[2].trim();
+			if (seenDefinitions[key] && seenDefinitions[key] !== definition) {
+				warnings.push(`${key} has conflicting duplicate definitions`);
+			}
+			seenDefinitions[key] = definition;
+		}
+
+		const fields = Object.entries(variables)
+			.filter(([name]) => name.startsWith('chat.variables.'))
+			.map(([name, field]) => ({ key: name.replace('chat.variables.', ''), ...(field as any) }));
+
+		for (const field of fields) {
+			const key = field.key;
+			if (!chatVariableKeyRegex.test(key)) {
+				warnings.push(`${key} must be lowercase snake case`);
+				continue;
+			}
+
+			if (
+				field.type === 'select' &&
+				(!Array.isArray(field.options) || field.options.length === 0)
+			) {
+				warnings.push(`${key} select needs options=[...]`);
+			}
+		}
+
+		return { fields, warnings };
+	};
+
+	$: chatVariablesPreview = getChatVariablesPreview(system ?? '');
+
 	const getBaseModelItems = (models: any[] = []) => {
 		const currentModelId = (model as any)?.id;
 
@@ -721,6 +762,44 @@
 											bind:value={system}
 										/>
 									</div>
+									{#if chatVariablesPreview.fields.length > 0 || chatVariablesPreview.warnings.length > 0}
+										<div class="mt-2 border-t border-gray-100/60 pt-2 dark:border-gray-850/60">
+											<div class="mb-1.5 flex items-center justify-between gap-2">
+												<div class="text-xs text-gray-500 dark:text-gray-400">
+													{$i18n.t('Detected Chat Variables')}
+												</div>
+												{#if chatVariablesPreview.fields.length > 0}
+													<div class="text-[0.6875rem] text-gray-400 dark:text-gray-600">
+														{chatVariablesPreview.fields.length}
+													</div>
+												{/if}
+											</div>
+
+											{#if chatVariablesPreview.fields.length > 0}
+												<div class="flex flex-wrap gap-x-3 gap-y-1.5 text-xs">
+													{#each chatVariablesPreview.fields as field}
+														<div class="flex items-center gap-1 text-gray-600 dark:text-gray-300">
+															<span class="font-medium">{field.key}</span>
+															<span class="text-gray-400 dark:text-gray-600">{field.type}</span>
+															{#if field.required}
+																<span class="text-amber-600 dark:text-amber-400">required</span>
+															{/if}
+														</div>
+													{/each}
+												</div>
+											{/if}
+
+											{#if chatVariablesPreview.warnings.length > 0}
+												<div
+													class="mt-2 flex flex-col gap-1 text-xs text-amber-600 dark:text-amber-400"
+												>
+													{#each chatVariablesPreview.warnings as warning}
+														<div>{warning}</div>
+													{/each}
+												</div>
+											{/if}
+										</div>
+									{/if}
 								</div>
 
 								<div class="flex h-7 w-full justify-between">