feat: UI template system for saving and reusing generated widgets

apps/agent/main.py

@@ -10,14 +10,15 @@
 from src.query import query_data
 from src.todos import AgentState, todo_tools
 from src.form import generate_form
+from src.templates import template_tools
 from skills import load_all_skills
 
 # Load all visualization skills
 _skills_text = load_all_skills()
 
 agent = create_agent(
     model=ChatOpenAI(model="gpt-5.4-2026-03-05"),
-    tools=[query_data, *todo_tools, generate_form],
+    tools=[query_data, *todo_tools, generate_form, *template_tools],
     middleware=[CopilotKitMiddleware()],
     state_schema=AgentState,
     system_prompt=f"""
@@ -47,6 +48,28 @@
         Follow the skills below for how to produce high-quality visuals:
 
         {_skills_text}
+
+        ## UI Templates
+
+        Users can save generated UIs as reusable templates and apply them later.
+        You have backend tools: `save_template`, `list_templates`, `apply_template`, `delete_template`.
+
+        **When a user asks to apply/recreate a template with new data:**
+        Check `pending_template` in state — the frontend sets this when the user picks a template.
+        If `pending_template` is present (has `id` and `name`):
+        1. Call `apply_template(template_id=pending_template["id"])` to retrieve the HTML
+        2. Take the returned HTML and COPY IT EXACTLY, only replacing the data values
+           (names, numbers, dates, labels, amounts) to match the user's message
+        3. Render the modified HTML using `widgetRenderer`
+        4. Call `clear_pending_template` to reset the pending state
+
+        If no `pending_template` is set but the user mentions a template by name, use
+        `apply_template(name="...")` instead.
+
+        CRITICAL: Do NOT rewrite or generate HTML from scratch. Take the original HTML string,
+        find-and-replace ONLY the data values, and pass the result to widgetRenderer.
+        This preserves the exact layout and styling of the original template.
+        For bar/pie chart templates, use `barChart` or `pieChart` component instead.
     """,
 )
 

apps/agent/src/templates.py

@@ -0,0 +1,258 @@
+from langchain.tools import ToolRuntime, tool
+from langchain.messages import ToolMessage
+from langgraph.types import Command
+from typing import Any, Optional, TypedDict
+import uuid
+from datetime import datetime
+
+
+class UITemplate(TypedDict, total=False):
+    id: str
+    name: str
+    description: str
+    html: str
+    data_description: str
+    created_at: str
+    version: int
+    component_type: Optional[str]
+    component_data: Optional[dict[str, Any]]
+
+
+# Built-in seed templates — must stay in sync with apps/app/src/components/template-library/seed-templates.ts
+# Only id, name, description, html, and data_description are needed for apply_template lookups.
+SEED_TEMPLATES: list[UITemplate] = [
+    {
+        "id": "seed-weather-001",
+        "name": "Weather",
+        "description": "Current weather conditions card with temperature, humidity, wind, and UV index",
+        "html": "",  # Populated at module load from _SEED_HTML below
+        "data_description": "City name, date, temperature, condition, humidity, wind speed/direction, UV index",
+        "version": 1,
+    },
+    {
+        "id": "seed-invoice-001",
+        "name": "Invoice Card",
+        "description": "Compact invoice card with amount, client info, and action buttons",
+        "html": "",
+        "data_description": "Title, amount, description, client name, billing month, invoice number, due date",
+        "version": 1,
+    },
+    {
+        "id": "seed-dashboard-001",
+        "name": "Dashboard",
+        "description": "KPI dashboard with metrics cards and bar chart for quarterly performance",
+        "html": "",
+        "data_description": "Title, subtitle, KPI labels/values/changes, monthly bar chart data, legend items",
+        "version": 1,
+    },
+]
+
+# Load seed HTML from the frontend source so there's a single source of truth.
+# If the file isn't available (e.g. in a standalone agent deploy), seeds will
+# still be discoverable by name but with empty HTML — the agent can regenerate.
+def _load_seed_html() -> None:
+    from pathlib import Path
+
+    seed_file = Path(__file__).resolve().parents[2] / "app" / "src" / "components" / "template-library" / "seed-templates.ts"
+    if not seed_file.exists():
+        return
+    text = seed_file.read_text()
+    # Map TS variable names to seed IDs
+    mapping = {
+        "weatherHtml": "seed-weather-001",
+        "invoiceHtml": "seed-invoice-001",
+        "dashboardHtml": "seed-dashboard-001",
+    }
+    for var_name, seed_id in mapping.items():
+        # Extract template literal content between first ` and last `
+        marker = f"const {var_name} = `"
+        start = text.find(marker)
+        if start == -1:
+            continue
+        start += len(marker)
+        end = text.find("`;", start)
+        if end == -1:
+            continue
+        html = text[start:end]
+        for seed in SEED_TEMPLATES:
+            if seed["id"] == seed_id:
+                seed["html"] = html
+                break
+
+_load_seed_html()
+
+
+@tool
+def save_template(
+    name: str,
+    description: str,
+    html: str,
+    data_description: str,
+    runtime: ToolRuntime,
+) -> Command:
+    """
+    Save a generated UI as a reusable template.
+    Call this when the user wants to save a widget/visualization they liked for reuse later.
+
+    Args:
+        name: Short name for the template (e.g. "Invoice", "Dashboard")
+        description: What the template displays or does
+        html: The raw HTML string of the widget to save as a template
+        data_description: Description of the data shape this template expects
+    """
+    templates = list(runtime.state.get("templates", []))
+
+    template: UITemplate = {
+        "id": str(uuid.uuid4()),
+        "name": name,
+        "description": description,
+        "html": html,
+        "data_description": data_description,
+        "created_at": datetime.now().isoformat(),
+        "version": 1,
+    }
+    templates.append(template)
+
+    return Command(update={
+        "templates": templates,
+        "messages": [
+            ToolMessage(
+                content=f"Template '{name}' saved successfully (id: {template['id']})",
+                tool_call_id=runtime.tool_call_id,
+            )
+        ],
+    })
+
+
+@tool
+def list_templates(runtime: ToolRuntime):
+    """
+    List all saved UI templates, including built-in seed templates.
+    Returns template summaries (id, name, description, data_description).
+    """
+    state_templates = runtime.state.get("templates", [])
+    state_ids = {t["id"] for t in state_templates}
+    templates = [*state_templates, *(s for s in SEED_TEMPLATES if s["id"] not in state_ids)]
+    return [
+        {
+            "id": t["id"],
+            "name": t["name"],
+            "description": t["description"],
+            "data_description": t["data_description"],
+            "version": t["version"],
+        }
+        for t in templates
+    ]
+
+
+@tool
+def apply_template(runtime: ToolRuntime, name: str = "", template_id: str = ""):
+    """
+    Retrieve a saved template's HTML so you can adapt it with new data.
+    After calling this, generate a NEW widget in the same style and render via widgetRenderer.
+
+    This tool automatically checks for a pending_template in state (set by the
+    frontend when the user picks a template from the library). If pending_template
+    is present, it takes priority over name/template_id arguments.
+
+    Also searches built-in seed templates, so users can apply them by name in chat
+    even if the frontend hasn't pushed them into agent state yet.
+
+    Args:
+        name: The name of the template to apply (fallback if no pending_template)
+        template_id: The ID of the template to apply (fallback if no pending_template)
+    """
+    state_templates = runtime.state.get("templates", [])
+    state_ids = {t["id"] for t in state_templates}
+    templates = [*state_templates, *(s for s in SEED_TEMPLATES if s["id"] not in state_ids)]
+
+    # Check pending_template from frontend first — this is the most reliable source
+    pending = runtime.state.get("pending_template")
+    if pending and pending.get("id"):
+        template_id = pending["id"]
+
+    # Look up by ID first
+    if template_id:
+        for t in templates:
+            if t["id"] == template_id:
+                return {
+                    "name": t["name"],
+                    "description": t["description"],
+                    "html": t["html"],
+                    "data_description": t.get("data_description", ""),
+                }
+        return {"error": f"Template with id '{template_id}' not found"}
+
+    # Look up by name (most recent match)
+    if name:
+        matches = [t for t in templates if t["name"].lower() == name.lower()]
+        if matches:
+            t = max(matches, key=lambda x: x.get("created_at", ""))
+            return {
+                "name": t["name"],
+                "description": t["description"],
+                "html": t["html"],
+                "data_description": t.get("data_description", ""),
+            }
+        return {"error": f"No template named '{name}' found"}
+
+    return {"error": "Provide either a name or template_id"}
+
+
+@tool
+def delete_template(template_id: str, runtime: ToolRuntime) -> Command:
+    """
+    Delete a saved UI template.
+
+    Args:
+        template_id: The ID of the template to delete
+    """
+    templates = list(runtime.state.get("templates", []))
+    original_len = len(templates)
+    templates = [t for t in templates if t["id"] != template_id]
+
+    if len(templates) == original_len:
+        return Command(update={
+            "messages": [
+                ToolMessage(
+                    content=f"Template with id '{template_id}' not found",
+                    tool_call_id=runtime.tool_call_id,
+                )
+            ],
+        })
+
+    return Command(update={
+        "templates": templates,
+        "messages": [
+            ToolMessage(
+                content=f"Template deleted successfully",
+                tool_call_id=runtime.tool_call_id,
+            )
+        ],
+    })
+
+
+@tool
+def clear_pending_template(runtime: ToolRuntime) -> Command:
+    """
+    Clear the pending_template from state after applying it.
+    Call this after you have finished applying a template.
+    """
+    return Command(update={
+        "pending_template": None,
+        "messages": [
+            ToolMessage(
+                content="Pending template cleared",
+                tool_call_id=runtime.tool_call_id,
+            )
+        ],
+    })
+
+
+template_tools = [
+    save_template,
+    list_templates,
+    apply_template,
+    delete_template,
+    clear_pending_template,
+]

apps/agent/src/todos.py

@@ -2,18 +2,26 @@
 from langchain.tools import ToolRuntime, tool
 from langchain.messages import ToolMessage
 from langgraph.types import Command
-from typing import TypedDict, Literal
+from typing import Optional, TypedDict, Literal
 import uuid
 
+from src.templates import UITemplate
+
 class Todo(TypedDict):
     id: str
     title: str
     description: str
     emoji: str
     status: Literal["pending", "completed"]
 
+class PendingTemplate(TypedDict, total=False):
+    id: str
+    name: str
+
 class AgentState(BaseAgentState):
     todos: list[Todo]
+    templates: list[UITemplate]
+    pending_template: Optional[PendingTemplate]
 
 @tool
 def manage_todos(todos: list[Todo], runtime: ToolRuntime) -> Command:

apps/app/src/app/globals.css

@@ -621,3 +621,24 @@ body, html {
 @keyframes spin {
   to { transform: rotate(360deg); }
 }
+
+/* Template save animations */
+@keyframes tmpl-pop {
+  0%   { transform: scale(0.8); opacity: 0; }
+  50%  { transform: scale(1.05); }
+  100% { transform: scale(1); opacity: 1; }
+}
+
+@keyframes tmpl-check {
+  to { stroke-dashoffset: 0; }
+}
+
+@keyframes tmpl-slideIn {
+  from { transform: translateY(-4px) scale(0.97); opacity: 0; }
+  to   { transform: translateY(0) scale(1); opacity: 1; }
+}
+
+@keyframes chipIn {
+  from { transform: scale(0.9); opacity: 0; }
+  to   { transform: scale(1); opacity: 1; }
+}

apps/app/src/app/layout.tsx

@@ -10,6 +10,8 @@ export default function RootLayout({children}: Readonly<{ children: React.ReactN
   return (
     <html lang="en">
       <head>
+        <title>Open Generative UI</title>
+        <link rel="icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>🪁</text></svg>" />
         <link rel="preconnect" href="https://fonts.googleapis.com" />
         <link rel="preconnect" href="https://fonts.gstatic.com" crossOrigin="anonymous" />
         <link