Merge branch 'main' into gl/feat/a2ui-extension

docs/docs.json

@@ -351,7 +351,9 @@
                       "en/learn/using-annotations",
                       "en/learn/execution-hooks",
                       "en/learn/llm-hooks",
-                      "en/learn/tool-hooks"
+                      "en/learn/tool-hooks",
+                      "en/learn/a2a-agent-delegation",
+                      "en/learn/a2ui"
                     ]
                   },
                   {
@@ -810,7 +812,9 @@
                       "en/learn/using-annotations",
                       "en/learn/execution-hooks",
                       "en/learn/llm-hooks",
-                      "en/learn/tool-hooks"
+                      "en/learn/tool-hooks",
+                      "en/learn/a2a-agent-delegation",
+                      "en/learn/a2ui"
                     ]
                   },
                   {

docs/en/learn/a2ui.mdx

@@ -0,0 +1,344 @@
+---
+title: Agent-to-UI (A2UI) Protocol
+description: Enable agents to generate declarative UI surfaces for rich client rendering via the A2UI extension.
+icon: window-restore
+mode: "wide"
+---
+
+## A2UI Overview
+
+A2UI is a declarative UI protocol extension for [A2A](/en/learn/a2a-agent-delegation) that lets agents emit structured JSON messages describing interactive surfaces. Clients receive these messages and render them as rich UI components — forms, cards, lists, modals, and more — without the agent needing to know anything about the client's rendering stack.
+
+A2UI is built on the A2A extension mechanism and identified by the URI `https://a2ui.org/a2a-extension/a2ui/v0.8`.
+
+<Note>
+  A2UI requires the `a2a-sdk` package. Install with: `uv add 'crewai[a2a]'` or `pip install 'crewai[a2a]'`
+</Note>
+
+## How It Works
+
+1. The **server extension** scans agent output for A2UI JSON objects
+2. Valid messages are wrapped as `DataPart` entries with the `application/json+a2ui` MIME type
+3. The **client extension** augments the agent's system prompt with A2UI instructions and the component catalog
+4. The client tracks surface state (active surfaces and data models) across conversation turns
+
+## Server Setup
+
+Add `A2UIServerExtension` to your `A2AServerConfig` to enable A2UI output:
+
+```python Code
+from crewai import Agent
+from crewai.a2a import A2AServerConfig
+from crewai.a2a.extensions.a2ui import A2UIServerExtension
+
+agent = Agent(
+    role="Dashboard Agent",
+    goal="Present data through interactive UI surfaces",
+    backstory="Expert at building clear, actionable dashboards",
+    llm="gpt-4o",
+    a2a=A2AServerConfig(
+        url="https://your-server.com",
+        extensions=[A2UIServerExtension()],
+    ),
+)
+```
+
+### Server Extension Options
+
+<ParamField path="catalog_ids" type="list[str] | None" default="None">
+  Component catalog identifiers the server supports. When set, only these catalogs are advertised to clients.
+</ParamField>
+
+<ParamField path="accept_inline_catalogs" type="bool" default="False">
+  Whether to accept inline catalog definitions from clients in addition to named catalogs.
+</ParamField>
+
+## Client Setup
+
+Add `A2UIClientExtension` to your `A2AClientConfig` to enable A2UI rendering:
+
+```python Code
+from crewai import Agent
+from crewai.a2a import A2AClientConfig
+from crewai.a2a.extensions.a2ui import A2UIClientExtension
+
+agent = Agent(
+    role="UI Coordinator",
+    goal="Coordinate tasks and render agent responses as rich UI",
+    backstory="Expert at presenting agent output in interactive formats",
+    llm="gpt-4o",
+    a2a=A2AClientConfig(
+        endpoint="https://dashboard-agent.example.com/.well-known/agent-card.json",
+        extensions=[A2UIClientExtension()],
+    ),
+)
+```
+
+### Client Extension Options
+
+<ParamField path="catalog_id" type="str | None" default="None">
+  Preferred component catalog identifier. Defaults to `"standard (v0.8)"` when not set.
+</ParamField>
+
+<ParamField path="allowed_components" type="list[str] | None" default="None">
+  Restrict which components the agent may use. When `None`, all 18 standard catalog components are available.
+</ParamField>
+
+## Message Types
+
+A2UI defines four server-to-client message types. Each message targets a **surface** identified by `surfaceId`.
+
+<Tabs>
+  <Tab title="beginRendering">
+  Initializes a new surface with a root component and optional styles.
+
+  ```json
+  {
+    "beginRendering": {
+      "surfaceId": "dashboard-1",
+      "root": "main-column",
+      "catalogId": "standard (v0.8)",
+      "styles": {
+        "primaryColor": "#EB6658"
+      }
+    }
+  }
+  ```
+  </Tab>
+
+  <Tab title="surfaceUpdate">
+  Sends or updates one or more components on an existing surface.
+
+  ```json
+  {
+    "surfaceUpdate": {
+      "surfaceId": "dashboard-1",
+      "components": [
+        {
+          "id": "main-column",
+          "component": {
+            "Column": {
+              "children": { "explicitList": ["title", "content"] },
+              "alignment": "start"
+            }
+          }
+        },
+        {
+          "id": "title",
+          "component": {
+            "Text": {
+              "text": { "literalString": "Dashboard" },
+              "usageHint": "h1"
+            }
+          }
+        }
+      ]
+    }
+  }
+  ```
+  </Tab>
+
+  <Tab title="dataModelUpdate">
+  Updates the data model bound to a surface, enabling dynamic content.
+
+  ```json
+  {
+    "dataModelUpdate": {
+      "surfaceId": "dashboard-1",
+      "path": "/data/model",
+      "contents": [
+        {
+          "key": "userName",
+          "valueString": "Alice"
+        },
+        {
+          "key": "score",
+          "valueNumber": 42
+        }
+      ]
+    }
+  }
+  ```
+  </Tab>
+
+  <Tab title="deleteSurface">
+  Removes a surface and all its components.
+
+  ```json
+  {
+    "deleteSurface": {
+      "surfaceId": "dashboard-1"
+    }
+  }
+  ```
+  </Tab>
+</Tabs>
+
+## Component Catalog
+
+A2UI ships with 18 standard components organized into three categories:
+
+### Content
+
+| Component | Description | Required Fields |
+|-----------|-------------|-----------------|
+| **Text** | Renders text with optional heading/body hints | `text` (StringBinding) |
+| **Image** | Displays an image with fit and size options | `url` (StringBinding) |
+| **Icon** | Renders a named icon from a set of 47 icons | `name` (IconBinding) |
+| **Video** | Embeds a video player | `url` (StringBinding) |
+| **AudioPlayer** | Embeds an audio player with optional description | `url` (StringBinding) |
+
+### Layout
+
+| Component | Description | Required Fields |
+|-----------|-------------|-----------------|
+| **Row** | Horizontal flex container | `children` (ChildrenDef) |
+| **Column** | Vertical flex container | `children` (ChildrenDef) |
+| **List** | Scrollable list (vertical or horizontal) | `children` (ChildrenDef) |
+| **Card** | Elevated container for a single child | `child` (str) |
+| **Tabs** | Tabbed container | `tabItems` (list of TabItem) |
+| **Divider** | Visual separator (horizontal or vertical) | — |
+| **Modal** | Overlay triggered by an entry point | `entryPointChild`, `contentChild` (str) |
+
+### Interactive
+
+| Component | Description | Required Fields |
+|-----------|-------------|-----------------|
+| **Button** | Clickable button that triggers an action | `child` (str), `action` (Action) |
+| **CheckBox** | Boolean toggle with a label | `label` (StringBinding), `value` (BooleanBinding) |
+| **TextField** | Text input with type and validation options | `label` (StringBinding) |
+| **DateTimeInput** | Date and/or time picker | `value` (StringBinding) |
+| **MultipleChoice** | Selection from a list of options | `selections` (ArrayBinding), `options` (list) |
+| **Slider** | Numeric range slider | `value` (NumberBinding) |
+
+## Data Binding
+
+Components reference values through **bindings** rather than raw literals. This allows surfaces to update dynamically when the data model changes.
+
+There are two ways to bind a value:
+
+- **Literal values** — hardcoded directly in the component definition
+- **Path references** — point to a key in the surface's data model
+
+```json
+{
+  "surfaceUpdate": {
+    "surfaceId": "profile-1",
+    "components": [
+      {
+        "id": "greeting",
+        "component": {
+          "Text": {
+            "text": { "path": "/data/model/userName" },
+            "usageHint": "h2"
+          }
+        }
+      },
+      {
+        "id": "status",
+        "component": {
+          "Text": {
+            "text": { "literalString": "Online" },
+            "usageHint": "caption"
+          }
+        }
+      }
+    ]
+  }
+}
+```
+
+In this example, `greeting` reads the user's name from the data model (updated via `dataModelUpdate`), while `status` uses a hardcoded literal.
+
+## Handling User Actions
+
+Interactive components like `Button` trigger `userAction` events that flow back to the server. Each action includes a `name`, the originating `surfaceId` and `sourceComponentId`, and an optional `context` with key-value pairs.
+
+```json
+{
+  "userAction": {
+    "name": "submitForm",
+    "surfaceId": "form-1",
+    "sourceComponentId": "submit-btn",
+    "timestamp": "2026-03-12T10:00:00Z",
+    "context": {
+      "selectedOption": "optionA"
+    }
+  }
+}
+```
+
+Action context values can also use path bindings to send current data model values back to the server:
+
+```json
+{
+  "Button": {
+    "child": "confirm-label",
+    "action": {
+      "name": "confirm",
+      "context": [
+        {
+          "key": "currentScore",
+          "value": { "path": "/data/model/score" }
+        }
+      ]
+    }
+  }
+}
+```
+
+## Validation
+
+Use `validate_a2ui_message` to validate server-to-client messages and `validate_a2ui_event` for client-to-server events:
+
+```python Code
+from crewai.a2a.extensions.a2ui import validate_a2ui_message
+from crewai.a2a.extensions.a2ui.validator import (
+    validate_a2ui_event,
+    A2UIValidationError,
+)
+
+# Validate a server message
+try:
+    msg = validate_a2ui_message({"beginRendering": {"surfaceId": "s1", "root": "r1"}})
+except A2UIValidationError as exc:
+    print(exc.errors)
+
+# Validate a client event
+try:
+    event = validate_a2ui_event({
+        "userAction": {
+            "name": "click",
+            "surfaceId": "s1",
+            "sourceComponentId": "btn-1",
+            "timestamp": "2026-03-12T10:00:00Z",
+        }
+    })
+except A2UIValidationError as exc:
+    print(exc.errors)
+```
+
+## Best Practices
+
+<CardGroup cols={2}>
+  <Card title="Start Simple" icon="play">
+    Begin with a `beginRendering` message and a single `surfaceUpdate`. Add data binding and interactivity once the basic flow works.
+  </Card>
+
+  <Card title="Use Data Binding for Dynamic Content" icon="arrows-rotate">
+    Prefer path bindings over literal values for content that changes. Use `dataModelUpdate` to push new values without resending the full component tree.
+  </Card>
+
+  <Card title="Filter Components" icon="filter">
+    Use the `allowed_components` option on `A2UIClientExtension` to restrict which components the agent may emit, reducing prompt size and keeping output predictable.
+  </Card>
+
+  <Card title="Validate Messages" icon="check">
+    Use `validate_a2ui_message` and `validate_a2ui_event` to catch malformed payloads early, especially when building custom integrations.
+  </Card>
+</CardGroup>
+
+## Learn More
+
+- [A2A Agent Delegation](/en/learn/a2a-agent-delegation) — configure agents for remote delegation via the A2A protocol
+- [A2A Protocol Documentation](https://a2a-protocol.org) — official protocol specification

lib/crewai/src/crewai/a2a/extensions/a2ui/__init__.py

@@ -0,0 +1,68 @@
+"""A2UI (Agent to UI) declarative UI protocol support for CrewAI."""
+
+from crewai.a2a.extensions.a2ui.catalog import (
+    AudioPlayer,
+    Button,
+    Card,
+    CheckBox,
+    Column,
+    DateTimeInput,
+    Divider,
+    Icon,
+    Image,
+    List,
+    Modal,
+    MultipleChoice,
+    Row,
+    Slider,
+    Tabs,
+    Text,
+    TextField,
+    Video,
+)
+from crewai.a2a.extensions.a2ui.client_extension import A2UIClientExtension
+from crewai.a2a.extensions.a2ui.models import (
+    A2UIEvent,
+    A2UIMessage,
+    A2UIResponse,
+    BeginRendering,
+    DataModelUpdate,
+    DeleteSurface,
+    SurfaceUpdate,
+    UserAction,
+)
+from crewai.a2a.extensions.a2ui.server_extension import A2UIServerExtension
+from crewai.a2a.extensions.a2ui.validator import validate_a2ui_message
+
+
+__all__ = [
+    "A2UIClientExtension",
+    "A2UIEvent",
+    "A2UIMessage",
+    "A2UIResponse",
+    "A2UIServerExtension",
+    "AudioPlayer",
+    "BeginRendering",
+    "Button",
+    "Card",
+    "CheckBox",
+    "Column",
+    "DataModelUpdate",
+    "DateTimeInput",
+    "DeleteSurface",
+    "Divider",
+    "Icon",
+    "Image",
+    "List",
+    "Modal",
+    "MultipleChoice",
+    "Row",
+    "Slider",
+    "SurfaceUpdate",
+    "Tabs",
+    "Text",
+    "TextField",
+    "UserAction",
+    "Video",
+    "validate_a2ui_message",
+]

lib/crewai/src/crewai/a2a/extensions/a2ui/catalog.py

@@ -0,0 +1,381 @@
+"""Typed helpers for A2UI standard catalog components.
+
+These models provide optional type safety for standard catalog components.
+Agents can also use raw dicts validated against the JSON schema.
+"""
+
+from __future__ import annotations
+
+from typing import Literal
+
+from pydantic import BaseModel, Field
+
+
+class StringBinding(BaseModel):
+    """A string value: literal or data-model path."""
+
+    literal_string: str | None = Field(None, alias="literalString")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class NumberBinding(BaseModel):
+    """A numeric value: literal or data-model path."""
+
+    literal_number: float | None = Field(None, alias="literalNumber")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class BooleanBinding(BaseModel):
+    """A boolean value: literal or data-model path."""
+
+    literal_boolean: bool | None = Field(None, alias="literalBoolean")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class ArrayBinding(BaseModel):
+    """An array value: literal or data-model path."""
+
+    literal_array: list[str] | None = Field(None, alias="literalArray")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class ChildrenDef(BaseModel):
+    """Children definition for layout components."""
+
+    explicit_list: list[str] | None = Field(None, alias="explicitList")
+    template: ChildTemplate | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class ChildTemplate(BaseModel):
+    """Template for generating dynamic children from a data model list."""
+
+    component_id: str = Field(alias="componentId")
+    data_binding: str = Field(alias="dataBinding")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class ActionContextEntry(BaseModel):
+    """A key-value pair in an action context payload."""
+
+    key: str
+    value: ActionBoundValue
+
+    model_config = {"extra": "forbid"}
+
+
+class ActionBoundValue(BaseModel):
+    """A value in an action context: literal or data-model path."""
+
+    path: str | None = None
+    literal_string: str | None = Field(None, alias="literalString")
+    literal_number: float | None = Field(None, alias="literalNumber")
+    literal_boolean: bool | None = Field(None, alias="literalBoolean")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Action(BaseModel):
+    """Client-side action dispatched by interactive components."""
+
+    name: str
+    context: list[ActionContextEntry] | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class TabItem(BaseModel):
+    """A single tab definition."""
+
+    title: StringBinding
+    child: str
+
+    model_config = {"extra": "forbid"}
+
+
+class MultipleChoiceOption(BaseModel):
+    """A single option in a MultipleChoice component."""
+
+    label: StringBinding
+    value: str
+
+    model_config = {"extra": "forbid"}
+
+
+class Text(BaseModel):
+    """Displays text content."""
+
+    text: StringBinding
+    usage_hint: Literal["h1", "h2", "h3", "h4", "h5", "caption", "body"] | None = Field(
+        None, alias="usageHint"
+    )
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Image(BaseModel):
+    """Displays an image."""
+
+    url: StringBinding
+    fit: Literal["contain", "cover", "fill", "none", "scale-down"] | None = None
+    usage_hint: (
+        Literal[
+            "icon", "avatar", "smallFeature", "mediumFeature", "largeFeature", "header"
+        ]
+        | None
+    ) = Field(None, alias="usageHint")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+IconName = Literal[
+    "accountCircle",
+    "add",
+    "arrowBack",
+    "arrowForward",
+    "attachFile",
+    "calendarToday",
+    "call",
+    "camera",
+    "check",
+    "close",
+    "delete",
+    "download",
+    "edit",
+    "event",
+    "error",
+    "favorite",
+    "favoriteOff",
+    "folder",
+    "help",
+    "home",
+    "info",
+    "locationOn",
+    "lock",
+    "lockOpen",
+    "mail",
+    "menu",
+    "moreVert",
+    "moreHoriz",
+    "notificationsOff",
+    "notifications",
+    "payment",
+    "person",
+    "phone",
+    "photo",
+    "print",
+    "refresh",
+    "search",
+    "send",
+    "settings",
+    "share",
+    "shoppingCart",
+    "star",
+    "starHalf",
+    "starOff",
+    "upload",
+    "visibility",
+    "visibilityOff",
+    "warning",
+]
+
+
+class IconBinding(BaseModel):
+    """Icon name: literal enum or data-model path."""
+
+    literal_string: IconName | None = Field(None, alias="literalString")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Icon(BaseModel):
+    """Displays a named icon."""
+
+    name: IconBinding
+
+    model_config = {"extra": "forbid"}
+
+
+class Video(BaseModel):
+    """Displays a video player."""
+
+    url: StringBinding
+
+    model_config = {"extra": "forbid"}
+
+
+class AudioPlayer(BaseModel):
+    """Displays an audio player."""
+
+    url: StringBinding
+    description: StringBinding | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class Row(BaseModel):
+    """Horizontal layout container."""
+
+    children: ChildrenDef
+    distribution: (
+        Literal["center", "end", "spaceAround", "spaceBetween", "spaceEvenly", "start"]
+        | None
+    ) = None
+    alignment: Literal["start", "center", "end", "stretch"] | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class Column(BaseModel):
+    """Vertical layout container."""
+
+    children: ChildrenDef
+    distribution: (
+        Literal["start", "center", "end", "spaceBetween", "spaceAround", "spaceEvenly"]
+        | None
+    ) = None
+    alignment: Literal["center", "end", "start", "stretch"] | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class List(BaseModel):
+    """Scrollable list container."""
+
+    children: ChildrenDef
+    direction: Literal["vertical", "horizontal"] | None = None
+    alignment: Literal["start", "center", "end", "stretch"] | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class Card(BaseModel):
+    """Card container wrapping a single child."""
+
+    child: str
+
+    model_config = {"extra": "forbid"}
+
+
+class Tabs(BaseModel):
+    """Tabbed navigation container."""
+
+    tab_items: list[TabItem] = Field(alias="tabItems")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Divider(BaseModel):
+    """A visual divider line."""
+
+    axis: Literal["horizontal", "vertical"] | None = None
+
+    model_config = {"extra": "forbid"}
+
+
+class Modal(BaseModel):
+    """A modal dialog with an entry point trigger and content."""
+
+    entry_point_child: str = Field(alias="entryPointChild")
+    content_child: str = Field(alias="contentChild")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Button(BaseModel):
+    """An interactive button with an action."""
+
+    child: str
+    primary: bool | None = None
+    action: Action
+
+    model_config = {"extra": "forbid"}
+
+
+class CheckBox(BaseModel):
+    """A checkbox input."""
+
+    label: StringBinding
+    value: BooleanBinding
+
+    model_config = {"extra": "forbid"}
+
+
+class TextField(BaseModel):
+    """A text input field."""
+
+    label: StringBinding
+    text: StringBinding | None = None
+    text_field_type: (
+        Literal["date", "longText", "number", "shortText", "obscured"] | None
+    ) = Field(None, alias="textFieldType")
+    validation_regexp: str | None = Field(None, alias="validationRegexp")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class DateTimeInput(BaseModel):
+    """A date and/or time picker."""
+
+    value: StringBinding
+    enable_date: bool | None = Field(None, alias="enableDate")
+    enable_time: bool | None = Field(None, alias="enableTime")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class MultipleChoice(BaseModel):
+    """A multiple-choice selection component."""
+
+    selections: ArrayBinding
+    options: list[MultipleChoiceOption]
+    max_allowed_selections: int | None = Field(None, alias="maxAllowedSelections")
+    variant: Literal["checkbox", "chips"] | None = None
+    filterable: bool | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class Slider(BaseModel):
+    """A numeric slider input."""
+
+    value: NumberBinding
+    min_value: float | None = Field(None, alias="minValue")
+    max_value: float | None = Field(None, alias="maxValue")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+STANDARD_CATALOG_COMPONENTS: frozenset[str] = frozenset(
+    {
+        "Text",
+        "Image",
+        "Icon",
+        "Video",
+        "AudioPlayer",
+        "Row",
+        "Column",
+        "List",
+        "Card",
+        "Tabs",
+        "Divider",
+        "Modal",
+        "Button",
+        "CheckBox",
+        "TextField",
+        "DateTimeInput",
+        "MultipleChoice",
+        "Slider",
+    }
+)

lib/crewai/src/crewai/a2a/extensions/a2ui/client_extension.py

@@ -0,0 +1,184 @@
+"""A2UI client extension for the A2A protocol."""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+from dataclasses import dataclass, field
+import logging
+from typing import TYPE_CHECKING, Any
+
+from crewai.a2a.extensions.a2ui.models import extract_a2ui_json_objects
+from crewai.a2a.extensions.a2ui.prompt import build_a2ui_system_prompt
+from crewai.a2a.extensions.a2ui.server_extension import A2UI_MIME_TYPE
+from crewai.a2a.extensions.a2ui.validator import (
+    A2UIValidationError,
+    validate_a2ui_message,
+)
+
+
+if TYPE_CHECKING:
+    from a2a.types import Message
+
+    from crewai.agent.core import Agent
+
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class A2UIConversationState:
+    """Tracks active A2UI surfaces and data models across a conversation."""
+
+    active_surfaces: dict[str, dict[str, Any]] = field(default_factory=dict)
+    data_models: dict[str, list[dict[str, Any]]] = field(default_factory=dict)
+    last_a2ui_messages: list[dict[str, Any]] = field(default_factory=list)
+
+    def is_ready(self) -> bool:
+        """Return True when at least one surface is active."""
+        return bool(self.active_surfaces)
+
+
+class A2UIClientExtension:
+    """A2A client extension that adds A2UI support to agents.
+
+    Implements the ``A2AExtension`` protocol to inject A2UI prompt
+    instructions, track UI state across conversations, and validate
+    A2UI messages in responses.
+
+    Example::
+
+        A2AClientConfig(
+            endpoint="...",
+            extensions=["https://a2ui.org/a2a-extension/a2ui/v0.8"],
+            client_extensions=[A2UIClientExtension()],
+        )
+    """
+
+    def __init__(
+        self,
+        catalog_id: str | None = None,
+        allowed_components: list[str] | None = None,
+    ) -> None:
+        """Initialize the A2UI client extension.
+
+        Args:
+            catalog_id: Catalog identifier to use for prompt generation.
+            allowed_components: Subset of component names to expose to the agent.
+        """
+        self._catalog_id = catalog_id
+        self._allowed_components = allowed_components
+
+    def inject_tools(self, agent: Agent) -> None:
+        """No-op — A2UI uses prompt augmentation rather than tool injection."""
+
+    def extract_state_from_history(
+        self, conversation_history: Sequence[Message]
+    ) -> A2UIConversationState | None:
+        """Scan conversation history for A2UI DataParts and track surface state."""
+        state = A2UIConversationState()
+
+        for message in conversation_history:
+            if not _has_parts(message):
+                continue
+            for part in message.parts:
+                root = part.root
+                if root.kind != "data":
+                    continue
+                metadata = root.metadata or {}
+                mime_type = metadata.get("mimeType", "")
+                if mime_type != A2UI_MIME_TYPE:
+                    continue
+
+                data = root.data
+                if not isinstance(data, dict):
+                    continue
+
+                surface_id = _get_surface_id(data)
+                if not surface_id:
+                    continue
+
+                if "deleteSurface" in data:
+                    state.active_surfaces.pop(surface_id, None)
+                    state.data_models.pop(surface_id, None)
+                elif "beginRendering" in data:
+                    state.active_surfaces[surface_id] = data["beginRendering"]
+                elif "surfaceUpdate" in data:
+                    state.active_surfaces[surface_id] = data["surfaceUpdate"]
+                elif "dataModelUpdate" in data:
+                    contents = data["dataModelUpdate"].get("contents", [])
+                    state.data_models.setdefault(surface_id, []).extend(contents)
+
+        if not state.active_surfaces and not state.data_models:
+            return None
+        return state
+
+    def augment_prompt(
+        self,
+        base_prompt: str,
+        conversation_state: A2UIConversationState | None,
+    ) -> str:
+        """Append A2UI system prompt instructions to the base prompt."""
+        a2ui_prompt = build_a2ui_system_prompt(
+            catalog_id=self._catalog_id,
+            allowed_components=self._allowed_components,
+        )
+        return f"{base_prompt}\n\n{a2ui_prompt}"
+
+    def process_response(
+        self,
+        agent_response: Any,
+        conversation_state: A2UIConversationState | None,
+    ) -> Any:
+        """Extract and validate A2UI JSON from agent output.
+
+        Stores extracted A2UI messages on the conversation state and returns
+        the original response unchanged to preserve the AgentResponseProtocol
+        contract.
+        """
+        text = (
+            agent_response if isinstance(agent_response, str) else str(agent_response)
+        )
+        a2ui_messages = _extract_and_validate(text)
+
+        if a2ui_messages and conversation_state is not None:
+            conversation_state.last_a2ui_messages = a2ui_messages
+
+        return agent_response
+
+
+def _has_parts(message: Any) -> bool:
+    """Check if a message has a parts attribute."""
+    return isinstance(getattr(message, "parts", None), list)
+
+
+def _get_surface_id(data: dict[str, Any]) -> str | None:
+    """Extract surfaceId from any A2UI message type."""
+    for key in ("beginRendering", "surfaceUpdate", "dataModelUpdate", "deleteSurface"):
+        inner = data.get(key)
+        if isinstance(inner, dict):
+            sid = inner.get("surfaceId")
+            if isinstance(sid, str):
+                return sid
+    return None
+
+
+def _extract_and_validate(text: str) -> list[dict[str, Any]]:
+    """Extract A2UI JSON objects from text and validate them."""
+    return [
+        dumped
+        for candidate in extract_a2ui_json_objects(text)
+        if (dumped := _try_validate(candidate)) is not None
+    ]
+
+
+def _try_validate(candidate: dict[str, Any]) -> dict[str, Any] | None:
+    """Validate a single A2UI candidate, returning None on failure."""
+    try:
+        msg = validate_a2ui_message(candidate)
+    except A2UIValidationError:
+        logger.debug(
+            "Skipping invalid A2UI candidate in agent output",
+            exc_info=True,
+        )
+        return None
+    return msg.model_dump(by_alias=True, exclude_none=True)

lib/crewai/src/crewai/a2a/extensions/a2ui/models.py

@@ -0,0 +1,212 @@
+"""Pydantic models for A2UI server-to-client messages and client-to-server events."""
+
+from __future__ import annotations
+
+import json
+import re
+from typing import Any
+
+from pydantic import BaseModel, Field, model_validator
+
+
+class BoundValue(BaseModel):
+    """A value that can be a literal or a data-model path reference."""
+
+    literal_string: str | None = Field(None, alias="literalString")
+    literal_number: float | None = Field(None, alias="literalNumber")
+    literal_boolean: bool | None = Field(None, alias="literalBoolean")
+    literal_array: list[str] | None = Field(None, alias="literalArray")
+    path: str | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class MapEntry(BaseModel):
+    """A single entry in a valueMap adjacency list, supporting recursive nesting."""
+
+    key: str
+    value_string: str | None = Field(None, alias="valueString")
+    value_number: float | None = Field(None, alias="valueNumber")
+    value_boolean: bool | None = Field(None, alias="valueBoolean")
+    value_map: list[MapEntry] | None = Field(None, alias="valueMap")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class DataEntry(BaseModel):
+    """A data model entry with a key and exactly one typed value."""
+
+    key: str
+    value_string: str | None = Field(None, alias="valueString")
+    value_number: float | None = Field(None, alias="valueNumber")
+    value_boolean: bool | None = Field(None, alias="valueBoolean")
+    value_map: list[MapEntry] | None = Field(None, alias="valueMap")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+_HEX_COLOR_PATTERN: re.Pattern[str] = re.compile(r"^#[0-9a-fA-F]{6}$")
+
+
+class Styles(BaseModel):
+    """Surface styling information."""
+
+    font: str | None = None
+    primary_color: str | None = Field(
+        None, alias="primaryColor", pattern=_HEX_COLOR_PATTERN.pattern
+    )
+
+    model_config = {"populate_by_name": True, "extra": "allow"}
+
+
+class ComponentEntry(BaseModel):
+    """A single component in a UI widget tree.
+
+    The ``component`` dict must contain exactly one key — the component type
+    name (e.g. ``"Text"``, ``"Button"``) — whose value holds the component
+    properties.  Component internals are left as ``dict[str, Any]`` because
+    they are catalog-dependent; use the typed helpers in ``catalog.py`` for
+    the standard catalog.
+    """
+
+    id: str
+    weight: float | None = None
+    component: dict[str, Any]
+
+    model_config = {"extra": "forbid"}
+
+
+class BeginRendering(BaseModel):
+    """Signals the client to begin rendering a surface."""
+
+    surface_id: str = Field(alias="surfaceId")
+    root: str
+    catalog_id: str | None = Field(None, alias="catalogId")
+    styles: Styles | None = None
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class SurfaceUpdate(BaseModel):
+    """Updates a surface with a new set of components."""
+
+    surface_id: str = Field(alias="surfaceId")
+    components: list[ComponentEntry] = Field(min_length=1)
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class DataModelUpdate(BaseModel):
+    """Updates the data model for a surface."""
+
+    surface_id: str = Field(alias="surfaceId")
+    path: str | None = None
+    contents: list[DataEntry]
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class DeleteSurface(BaseModel):
+    """Signals the client to delete a surface."""
+
+    surface_id: str = Field(alias="surfaceId")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+
+class A2UIMessage(BaseModel):
+    """Union wrapper for the four server-to-client A2UI message types.
+
+    Exactly one of the fields must be set.
+    """
+
+    begin_rendering: BeginRendering | None = Field(None, alias="beginRendering")
+    surface_update: SurfaceUpdate | None = Field(None, alias="surfaceUpdate")
+    data_model_update: DataModelUpdate | None = Field(None, alias="dataModelUpdate")
+    delete_surface: DeleteSurface | None = Field(None, alias="deleteSurface")
+
+    model_config = {"populate_by_name": True, "extra": "forbid"}
+
+    @model_validator(mode="after")
+    def _check_exactly_one(self) -> A2UIMessage:
+        """Enforce the spec's exactly-one-of constraint."""
+        fields = [
+            self.begin_rendering,
+            self.surface_update,
+            self.data_model_update,
+            self.delete_surface,
+        ]
+        count = sum(f is not None for f in fields)
+        if count != 1:
+            raise ValueError(f"Exactly one A2UI message type must be set, got {count}")
+        return self
+
+
+class UserAction(BaseModel):
+    """Reports a user-initiated action from a component."""
+
+    name: str
+    surface_id: str = Field(alias="surfaceId")
+    source_component_id: str = Field(alias="sourceComponentId")
+    timestamp: str
+    context: dict[str, Any]
+
+    model_config = {"populate_by_name": True}
+
+
+class ClientError(BaseModel):
+    """Reports a client-side error."""
+
+    model_config = {"extra": "allow"}
+
+
+class A2UIEvent(BaseModel):
+    """Union wrapper for client-to-server events."""
+
+    user_action: UserAction | None = Field(None, alias="userAction")
+    error: ClientError | None = None
+
+    model_config = {"populate_by_name": True}
+
+    @model_validator(mode="after")
+    def _check_exactly_one(self) -> A2UIEvent:
+        """Enforce the spec's exactly-one-of constraint."""
+        fields = [self.user_action, self.error]
+        count = sum(f is not None for f in fields)
+        if count != 1:
+            raise ValueError(f"Exactly one A2UI event type must be set, got {count}")
+        return self
+
+
+class A2UIResponse(BaseModel):
+    """Typed wrapper for responses containing A2UI messages."""
+
+    text: str
+    a2ui_parts: list[dict[str, Any]] = Field(default_factory=list)
+    a2ui_messages: list[dict[str, Any]] = Field(default_factory=list)
+
+
+_A2UI_KEYS = {"beginRendering", "surfaceUpdate", "dataModelUpdate", "deleteSurface"}
+
+
+def extract_a2ui_json_objects(text: str) -> list[dict[str, Any]]:
+    """Extract JSON objects containing A2UI keys from text.
+
+    Uses ``json.JSONDecoder.raw_decode`` for robust parsing that correctly
+    handles braces inside string literals.
+    """
+    decoder = json.JSONDecoder()
+    results: list[dict[str, Any]] = []
+    idx = 0
+    while idx < len(text):
+        idx = text.find("{", idx)
+        if idx == -1:
+            break
+        try:
+            obj, end_idx = decoder.raw_decode(text, idx)
+            if isinstance(obj, dict) and _A2UI_KEYS & obj.keys():
+                results.append(obj)
+            idx = end_idx
+        except json.JSONDecodeError:
+            idx += 1
+    return results

lib/crewai/src/crewai/a2a/extensions/a2ui/prompt.py

@@ -0,0 +1,75 @@
+"""System prompt generation for A2UI-capable agents."""
+
+from __future__ import annotations
+
+import json
+
+from crewai.a2a.extensions.a2ui.catalog import STANDARD_CATALOG_COMPONENTS
+from crewai.a2a.extensions.a2ui.schema import load_schema
+
+
+def build_a2ui_system_prompt(
+    catalog_id: str | None = None,
+    allowed_components: list[str] | None = None,
+) -> str:
+    """Build a system prompt fragment instructing the LLM to produce A2UI output.
+
+    The prompt describes the A2UI message format, available components, and
+    data binding rules.  It includes the resolved schema so the LLM can
+    generate structured output.
+
+    Args:
+        catalog_id: Catalog identifier to reference. Defaults to the
+            standard catalog for A2UI v0.8.
+        allowed_components: Subset of component names to expose.  When
+            ``None``, all standard catalog components are available.
+
+    Returns:
+        A system prompt string to append to the agent's instructions.
+    """
+    components = sorted(
+        allowed_components
+        if allowed_components is not None
+        else STANDARD_CATALOG_COMPONENTS
+    )
+
+    catalog_label = catalog_id or "standard (v0.8)"
+
+    resolved_schema = load_schema("server_to_client_with_standard_catalog")
+    schema_json = json.dumps(resolved_schema, indent=2)
+
+    return f"""\
+<A2UI_INSTRUCTIONS>
+You can generate rich, declarative UI by emitting A2UI JSON messages.
+
+CATALOG: {catalog_label}
+AVAILABLE COMPONENTS: {", ".join(components)}
+
+MESSAGE TYPES (emit exactly ONE per message):
+- beginRendering: Initialize a new surface with a root component and optional styles.
+- surfaceUpdate: Send/update components for a surface. Each component has a unique id \
+and a "component" wrapper containing exactly one component-type key.
+- dataModelUpdate: Update the data model for a surface. Data entries have a key and \
+one typed value (valueString, valueNumber, valueBoolean, valueMap).
+- deleteSurface: Remove a surface.
+
+DATA BINDING:
+- Use {{"literalString": "..."}} for inline string values.
+- Use {{"literalNumber": ...}} for inline numeric values.
+- Use {{"literalBoolean": ...}} for inline boolean values.
+- Use {{"literalArray": ["...", "..."]}} for inline array values.
+- Use {{"path": "/data/model/path"}} to bind to data model values.
+
+ACTIONS:
+- Interactive components (Button, etc.) have an "action" with a "name" and optional \
+"context" array of key/value pairs.
+- Values in action context can use data binding (path or literal).
+
+OUTPUT FORMAT:
+Emit each A2UI message as a valid JSON object. When generating UI, produce a \
+beginRendering message first, then surfaceUpdate messages with components, and \
+optionally dataModelUpdate messages to populate data-bound values.
+
+SCHEMA:
+{schema_json}
+</A2UI_INSTRUCTIONS>"""

lib/crewai/src/crewai/a2a/extensions/a2ui/schema/__init__.py

@@ -0,0 +1,48 @@
+"""Schema loading utilities for vendored A2UI JSON schemas."""
+
+from __future__ import annotations
+
+import json
+from pathlib import Path
+from typing import Any
+
+
+_SCHEMA_DIR = Path(__file__).parent / "v0_8"
+
+_SCHEMA_CACHE: dict[str, dict[str, Any]] = {}
+
+SCHEMA_NAMES: frozenset[str] = frozenset(
+    {
+        "server_to_client",
+        "client_to_server",
+        "standard_catalog_definition",
+        "server_to_client_with_standard_catalog",
+    }
+)
+
+
+def load_schema(name: str) -> dict[str, Any]:
+    """Load a vendored A2UI JSON schema by name.
+
+    Args:
+        name: Schema name without extension (e.g. ``"server_to_client"``).
+
+    Returns:
+        Parsed JSON schema dict.
+
+    Raises:
+        ValueError: If the schema name is not recognized.
+        FileNotFoundError: If the schema file is missing from the package.
+    """
+    if name not in SCHEMA_NAMES:
+        raise ValueError(f"Unknown schema {name!r}. Available: {sorted(SCHEMA_NAMES)}")
+
+    if name in _SCHEMA_CACHE:
+        return _SCHEMA_CACHE[name]
+
+    path = _SCHEMA_DIR / f"{name}.json"
+    with path.open() as f:
+        schema: dict[str, Any] = json.load(f)
+
+    _SCHEMA_CACHE[name] = schema
+    return schema

lib/crewai/src/crewai/a2a/extensions/a2ui/schema/v0_8/client_to_server.json

@@ -0,0 +1,53 @@
+{
+  "title": "A2UI (Agent to UI) Client-to-Server Event Schema",
+  "description": "Describes a JSON payload for a client-to-server event message.",
+  "type": "object",
+  "minProperties": 1,
+  "maxProperties": 1,
+  "properties": {
+    "userAction": {
+      "type": "object",
+      "description": "Reports a user-initiated action from a component.",
+      "properties": {
+        "name": {
+          "type": "string",
+          "description": "The name of the action, taken from the component's action.name property."
+        },
+        "surfaceId": {
+          "type": "string",
+          "description": "The id of the surface where the event originated."
+        },
+        "sourceComponentId": {
+          "type": "string",
+          "description": "The id of the component that triggered the event."
+        },
+        "timestamp": {
+          "type": "string",
+          "format": "date-time",
+          "description": "An ISO 8601 timestamp of when the event occurred."
+        },
+        "context": {
+          "type": "object",
+          "description": "A JSON object containing the key-value pairs from the component's action.context, after resolving all data bindings.",
+          "additionalProperties": true
+        }
+      },
+      "required": [
+        "name",
+        "surfaceId",
+        "sourceComponentId",
+        "timestamp",
+        "context"
+      ]
+    },
+    "error": {
+      "type": "object",
+      "description": "Reports a client-side error. The content is flexible.",
+      "additionalProperties": true
+    }
+  },
+  "oneOf": [
+    { "required": ["userAction"] },
+    { "required": ["error"] }
+  ]
+}

lib/crewai/src/crewai/a2a/extensions/a2ui/schema/v0_8/server_to_client.json

@@ -0,0 +1,148 @@
+{
+  "title": "A2UI Message Schema",
+  "description": "Describes a JSON payload for an A2UI (Agent to UI) message, which is used to dynamically construct and update user interfaces. A message MUST contain exactly ONE of the action properties: 'beginRendering', 'surfaceUpdate', 'dataModelUpdate', or 'deleteSurface'.",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "beginRendering": {
+      "type": "object",
+      "description": "Signals the client to begin rendering a surface with a root component and specific styles.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be rendered."
+        },
+        "catalogId": {
+          "type": "string",
+          "description": "The identifier of the component catalog to use for this surface. If omitted, the client MUST default to the standard catalog for this A2UI version (https://a2ui.org/specification/v0_8/standard_catalog_definition.json)."
+        },
+        "root": {
+          "type": "string",
+          "description": "The ID of the root component to render."
+        },
+        "styles": {
+          "type": "object",
+          "description": "Styling information for the UI.",
+          "additionalProperties": true
+        }
+      },
+      "required": ["root", "surfaceId"]
+    },
+    "surfaceUpdate": {
+      "type": "object",
+      "description": "Updates a surface with a new set of components.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be updated. If you are adding a new surface this *must* be a new, unique identified that has never been used for any existing surfaces shown."
+        },
+        "components": {
+          "type": "array",
+          "description": "A list containing all UI components for the surface.",
+          "minItems": 1,
+          "items": {
+            "type": "object",
+            "description": "Represents a *single* component in a UI widget tree. This component could be one of many supported types.",
+            "additionalProperties": false,
+            "properties": {
+              "id": {
+                "type": "string",
+                "description": "The unique identifier for this component."
+              },
+              "weight": {
+                "type": "number",
+                "description": "The relative weight of this component within a Row or Column. This corresponds to the CSS 'flex-grow' property. Note: this may ONLY be set when the component is a direct descendant of a Row or Column."
+              },
+              "component": {
+                "type": "object",
+                "description": "A wrapper object that MUST contain exactly one key, which is the name of the component type. The value is an object containing the properties for that specific component.",
+                "additionalProperties": true
+              }
+            },
+            "required": ["id", "component"]
+          }
+        }
+      },
+      "required": ["surfaceId", "components"]
+    },
+    "dataModelUpdate": {
+      "type": "object",
+      "description": "Updates the data model for a surface.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface this data model update applies to."
+        },
+        "path": {
+          "type": "string",
+          "description": "An optional path to a location within the data model (e.g., '/user/name'). If omitted, or set to '/', the entire data model will be replaced."
+        },
+        "contents": {
+          "type": "array",
+          "description": "An array of data entries. Each entry must contain a 'key' and exactly one corresponding typed 'value*' property.",
+          "items": {
+            "type": "object",
+            "description": "A single data entry. Exactly one 'value*' property should be provided alongside the key.",
+            "additionalProperties": false,
+            "properties": {
+              "key": {
+                "type": "string",
+                "description": "The key for this data entry."
+              },
+              "valueString": {
+                "type": "string"
+              },
+              "valueNumber": {
+                "type": "number"
+              },
+              "valueBoolean": {
+                "type": "boolean"
+              },
+              "valueMap": {
+                "description": "Represents a map as an adjacency list.",
+                "type": "array",
+                "items": {
+                  "type": "object",
+                  "description": "One entry in the map. Exactly one 'value*' property should be provided alongside the key.",
+                  "additionalProperties": false,
+                  "properties": {
+                    "key": {
+                      "type": "string"
+                    },
+                    "valueString": {
+                      "type": "string"
+                    },
+                    "valueNumber": {
+                      "type": "number"
+                    },
+                    "valueBoolean": {
+                      "type": "boolean"
+                    }
+                  },
+                  "required": ["key"]
+                }
+              }
+            },
+            "required": ["key"]
+          }
+        }
+      },
+      "required": ["contents", "surfaceId"]
+    },
+    "deleteSurface": {
+      "type": "object",
+      "description": "Signals the client to delete the surface identified by 'surfaceId'.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be deleted."
+        }
+      },
+      "required": ["surfaceId"]
+    }
+  }
+}

lib/crewai/src/crewai/a2a/extensions/a2ui/schema/v0_8/server_to_client_with_standard_catalog.json

@@ -0,0 +1,823 @@
+{
+  "title": "A2UI Message Schema",
+  "description": "Describes a JSON payload for an A2UI (Agent to UI) message, which is used to dynamically construct and update user interfaces. A message MUST contain exactly ONE of the action properties: 'beginRendering', 'surfaceUpdate', 'dataModelUpdate', or 'deleteSurface'.",
+  "type": "object",
+  "additionalProperties": false,
+  "properties": {
+    "beginRendering": {
+      "type": "object",
+      "description": "Signals the client to begin rendering a surface with a root component and specific styles.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be rendered."
+        },
+        "root": {
+          "type": "string",
+          "description": "The ID of the root component to render."
+        },
+        "styles": {
+          "type": "object",
+          "description": "Styling information for the UI.",
+          "additionalProperties": false,
+          "properties": {
+            "font": {
+              "type": "string",
+              "description": "The primary font for the UI."
+            },
+            "primaryColor": {
+              "type": "string",
+              "description": "The primary UI color as a hexadecimal code (e.g., '#00BFFF').",
+              "pattern": "^#[0-9a-fA-F]{6}$"
+            }
+          }
+        }
+      },
+      "required": ["root", "surfaceId"]
+    },
+    "surfaceUpdate": {
+      "type": "object",
+      "description": "Updates a surface with a new set of components.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be updated. If you are adding a new surface this *must* be a new, unique identified that has never been used for any existing surfaces shown."
+        },
+        "components": {
+          "type": "array",
+          "description": "A list containing all UI components for the surface.",
+          "minItems": 1,
+          "items": {
+            "type": "object",
+            "description": "Represents a *single* component in a UI widget tree. This component could be one of many supported types.",
+            "additionalProperties": false,
+            "properties": {
+              "id": {
+                "type": "string",
+                "description": "The unique identifier for this component."
+              },
+              "weight": {
+                "type": "number",
+                "description": "The relative weight of this component within a Row or Column. This corresponds to the CSS 'flex-grow' property. Note: this may ONLY be set when the component is a direct descendant of a Row or Column."
+              },
+              "component": {
+                "type": "object",
+                "description": "A wrapper object that MUST contain exactly one key, which is the name of the component type (e.g., 'Heading'). The value is an object containing the properties for that specific component.",
+                "additionalProperties": false,
+                "properties": {
+                  "Text": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "text": {
+                        "type": "object",
+                        "description": "The text content to display. This can be a literal string or a reference to a value in the data model ('path', e.g., '/doc/title'). While simple Markdown formatting is supported (i.e. without HTML, images, or links), utilizing dedicated UI components is generally preferred for a richer and more structured presentation.",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "usageHint": {
+                        "type": "string",
+                        "description": "A hint for the base text style. One of:\n- `h1`: Largest heading.\n- `h2`: Second largest heading.\n- `h3`: Third largest heading.\n- `h4`: Fourth largest heading.\n- `h5`: Fifth largest heading.\n- `caption`: Small text for captions.\n- `body`: Standard body text.",
+                        "enum": [
+                          "h1",
+                          "h2",
+                          "h3",
+                          "h4",
+                          "h5",
+                          "caption",
+                          "body"
+                        ]
+                      }
+                    },
+                    "required": ["text"]
+                  },
+                  "Image": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "url": {
+                        "type": "object",
+                        "description": "The URL of the image to display. This can be a literal string ('literal') or a reference to a value in the data model ('path', e.g. '/thumbnail/url').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "fit": {
+                        "type": "string",
+                        "description": "Specifies how the image should be resized to fit its container. This corresponds to the CSS 'object-fit' property.",
+                        "enum": [
+                          "contain",
+                          "cover",
+                          "fill",
+                          "none",
+                          "scale-down"
+                        ]
+                      },
+                      "usageHint": {
+                        "type": "string",
+                        "description": "A hint for the image size and style. One of:\n- `icon`: Small square icon.\n- `avatar`: Circular avatar image.\n- `smallFeature`: Small feature image.\n- `mediumFeature`: Medium feature image.\n- `largeFeature`: Large feature image.\n- `header`: Full-width, full bleed, header image.",
+                        "enum": [
+                          "icon",
+                          "avatar",
+                          "smallFeature",
+                          "mediumFeature",
+                          "largeFeature",
+                          "header"
+                        ]
+                      }
+                    },
+                    "required": ["url"]
+                  },
+                  "Icon": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "name": {
+                        "type": "object",
+                        "description": "The name of the icon to display. This can be a literal string or a reference to a value in the data model ('path', e.g. '/form/submit').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string",
+                            "enum": [
+                              "accountCircle",
+                              "add",
+                              "arrowBack",
+                              "arrowForward",
+                              "attachFile",
+                              "calendarToday",
+                              "call",
+                              "camera",
+                              "check",
+                              "close",
+                              "delete",
+                              "download",
+                              "edit",
+                              "event",
+                              "error",
+                              "favorite",
+                              "favoriteOff",
+                              "folder",
+                              "help",
+                              "home",
+                              "info",
+                              "locationOn",
+                              "lock",
+                              "lockOpen",
+                              "mail",
+                              "menu",
+                              "moreVert",
+                              "moreHoriz",
+                              "notificationsOff",
+                              "notifications",
+                              "payment",
+                              "person",
+                              "phone",
+                              "photo",
+                              "print",
+                              "refresh",
+                              "search",
+                              "send",
+                              "settings",
+                              "share",
+                              "shoppingCart",
+                              "star",
+                              "starHalf",
+                              "starOff",
+                              "upload",
+                              "visibility",
+                              "visibilityOff",
+                              "warning"
+                            ]
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      }
+                    },
+                    "required": ["name"]
+                  },
+                  "Video": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "url": {
+                        "type": "object",
+                        "description": "The URL of the video to display. This can be a literal string or a reference to a value in the data model ('path', e.g. '/video/url').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      }
+                    },
+                    "required": ["url"]
+                  },
+                  "AudioPlayer": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "url": {
+                        "type": "object",
+                        "description": "The URL of the audio to be played. This can be a literal string ('literal') or a reference to a value in the data model ('path', e.g. '/song/url').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "description": {
+                        "type": "object",
+                        "description": "A description of the audio, such as a title or summary. This can be a literal string or a reference to a value in the data model ('path', e.g. '/song/title').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      }
+                    },
+                    "required": ["url"]
+                  },
+                  "Row": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "children": {
+                        "type": "object",
+                        "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+                        "additionalProperties": false,
+                        "properties": {
+                          "explicitList": {
+                            "type": "array",
+                            "items": {
+                              "type": "string"
+                            }
+                          },
+                          "template": {
+                            "type": "object",
+                            "description": "A template for generating a dynamic list of children from a data model list. `componentId` is the component to use as a template, and `dataBinding` is the path to the map of components in the data model. Values in the map will define the list of children.",
+                            "additionalProperties": false,
+                            "properties": {
+                              "componentId": {
+                                "type": "string"
+                              },
+                              "dataBinding": {
+                                "type": "string"
+                              }
+                            },
+                            "required": ["componentId", "dataBinding"]
+                          }
+                        }
+                      },
+                      "distribution": {
+                        "type": "string",
+                        "description": "Defines the arrangement of children along the main axis (horizontally). This corresponds to the CSS 'justify-content' property.",
+                        "enum": [
+                          "center",
+                          "end",
+                          "spaceAround",
+                          "spaceBetween",
+                          "spaceEvenly",
+                          "start"
+                        ]
+                      },
+                      "alignment": {
+                        "type": "string",
+                        "description": "Defines the alignment of children along the cross axis (vertically). This corresponds to the CSS 'align-items' property.",
+                        "enum": ["start", "center", "end", "stretch"]
+                      }
+                    },
+                    "required": ["children"]
+                  },
+                  "Column": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "children": {
+                        "type": "object",
+                        "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+                        "additionalProperties": false,
+                        "properties": {
+                          "explicitList": {
+                            "type": "array",
+                            "items": {
+                              "type": "string"
+                            }
+                          },
+                          "template": {
+                            "type": "object",
+                            "description": "A template for generating a dynamic list of children from a data model list. `componentId` is the component to use as a template, and `dataBinding` is the path to the map of components in the data model. Values in the map will define the list of children.",
+                            "additionalProperties": false,
+                            "properties": {
+                              "componentId": {
+                                "type": "string"
+                              },
+                              "dataBinding": {
+                                "type": "string"
+                              }
+                            },
+                            "required": ["componentId", "dataBinding"]
+                          }
+                        }
+                      },
+                      "distribution": {
+                        "type": "string",
+                        "description": "Defines the arrangement of children along the main axis (vertically). This corresponds to the CSS 'justify-content' property.",
+                        "enum": [
+                          "start",
+                          "center",
+                          "end",
+                          "spaceBetween",
+                          "spaceAround",
+                          "spaceEvenly"
+                        ]
+                      },
+                      "alignment": {
+                        "type": "string",
+                        "description": "Defines the alignment of children along the cross axis (horizontally). This corresponds to the CSS 'align-items' property.",
+                        "enum": ["center", "end", "start", "stretch"]
+                      }
+                    },
+                    "required": ["children"]
+                  },
+                  "List": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "children": {
+                        "type": "object",
+                        "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+                        "additionalProperties": false,
+                        "properties": {
+                          "explicitList": {
+                            "type": "array",
+                            "items": {
+                              "type": "string"
+                            }
+                          },
+                          "template": {
+                            "type": "object",
+                            "description": "A template for generating a dynamic list of children from a data model list. `componentId` is the component to use as a template, and `dataBinding` is the path to the map of components in the data model. Values in the map will define the list of children.",
+                            "additionalProperties": false,
+                            "properties": {
+                              "componentId": {
+                                "type": "string"
+                              },
+                              "dataBinding": {
+                                "type": "string"
+                              }
+                            },
+                            "required": ["componentId", "dataBinding"]
+                          }
+                        }
+                      },
+                      "direction": {
+                        "type": "string",
+                        "description": "The direction in which the list items are laid out.",
+                        "enum": ["vertical", "horizontal"]
+                      },
+                      "alignment": {
+                        "type": "string",
+                        "description": "Defines the alignment of children along the cross axis.",
+                        "enum": ["start", "center", "end", "stretch"]
+                      }
+                    },
+                    "required": ["children"]
+                  },
+                  "Card": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "child": {
+                        "type": "string",
+                        "description": "The ID of the component to be rendered inside the card."
+                      }
+                    },
+                    "required": ["child"]
+                  },
+                  "Tabs": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "tabItems": {
+                        "type": "array",
+                        "description": "An array of objects, where each object defines a tab with a title and a child component.",
+                        "items": {
+                          "type": "object",
+                          "additionalProperties": false,
+                          "properties": {
+                            "title": {
+                              "type": "object",
+                              "description": "The tab title. Defines the value as either a literal value or a path to data model value (e.g. '/options/title').",
+                              "additionalProperties": false,
+                              "properties": {
+                                "literalString": {
+                                  "type": "string"
+                                },
+                                "path": {
+                                  "type": "string"
+                                }
+                              }
+                            },
+                            "child": {
+                              "type": "string"
+                            }
+                          },
+                          "required": ["title", "child"]
+                        }
+                      }
+                    },
+                    "required": ["tabItems"]
+                  },
+                  "Divider": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "axis": {
+                        "type": "string",
+                        "description": "The orientation of the divider.",
+                        "enum": ["horizontal", "vertical"]
+                      }
+                    }
+                  },
+                  "Modal": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "entryPointChild": {
+                        "type": "string",
+                        "description": "The ID of the component that opens the modal when interacted with (e.g., a button)."
+                      },
+                      "contentChild": {
+                        "type": "string",
+                        "description": "The ID of the component to be displayed inside the modal."
+                      }
+                    },
+                    "required": ["entryPointChild", "contentChild"]
+                  },
+                  "Button": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "child": {
+                        "type": "string",
+                        "description": "The ID of the component to display in the button, typically a Text component."
+                      },
+                      "primary": {
+                        "type": "boolean",
+                        "description": "Indicates if this button should be styled as the primary action."
+                      },
+                      "action": {
+                        "type": "object",
+                        "description": "The client-side action to be dispatched when the button is clicked. It includes the action's name and an optional context payload.",
+                        "additionalProperties": false,
+                        "properties": {
+                          "name": {
+                            "type": "string"
+                          },
+                          "context": {
+                            "type": "array",
+                            "items": {
+                              "type": "object",
+                              "additionalProperties": false,
+                              "properties": {
+                                "key": {
+                                  "type": "string"
+                                },
+                                "value": {
+                                  "type": "object",
+                                  "description": "Defines the value to be included in the context as either a literal value or a path to a data model value (e.g. '/user/name').",
+                                  "additionalProperties": false,
+                                  "properties": {
+                                    "path": {
+                                      "type": "string"
+                                    },
+                                    "literalString": {
+                                      "type": "string"
+                                    },
+                                    "literalNumber": {
+                                      "type": "number"
+                                    },
+                                    "literalBoolean": {
+                                      "type": "boolean"
+                                    }
+                                  }
+                                }
+                              },
+                              "required": ["key", "value"]
+                            }
+                          }
+                        },
+                        "required": ["name"]
+                      }
+                    },
+                    "required": ["child", "action"]
+                  },
+                  "CheckBox": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "label": {
+                        "type": "object",
+                        "description": "The text to display next to the checkbox. Defines the value as either a literal value or a path to data model ('path', e.g. '/option/label').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "value": {
+                        "type": "object",
+                        "description": "The current state of the checkbox (true for checked, false for unchecked). This can be a literal boolean ('literalBoolean') or a reference to a value in the data model ('path', e.g. '/filter/open').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalBoolean": {
+                            "type": "boolean"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      }
+                    },
+                    "required": ["label", "value"]
+                  },
+                  "TextField": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "label": {
+                        "type": "object",
+                        "description": "The text label for the input field. This can be a literal string or a reference to a value in the data model ('path, e.g. '/user/name').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "text": {
+                        "type": "object",
+                        "description": "The value of the text field. This can be a literal string or a reference to a value in the data model ('path', e.g. '/user/name').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "textFieldType": {
+                        "type": "string",
+                        "description": "The type of input field to display.",
+                        "enum": [
+                          "date",
+                          "longText",
+                          "number",
+                          "shortText",
+                          "obscured"
+                        ]
+                      },
+                      "validationRegexp": {
+                        "type": "string",
+                        "description": "A regular expression used for client-side validation of the input."
+                      }
+                    },
+                    "required": ["label"]
+                  },
+                  "DateTimeInput": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "value": {
+                        "type": "object",
+                        "description": "The selected date and/or time value in ISO 8601 format. This can be a literal string ('literalString') or a reference to a value in the data model ('path', e.g. '/user/dob').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalString": {
+                            "type": "string"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "enableDate": {
+                        "type": "boolean",
+                        "description": "If true, allows the user to select a date."
+                      },
+                      "enableTime": {
+                        "type": "boolean",
+                        "description": "If true, allows the user to select a time."
+                      }
+                    },
+                    "required": ["value"]
+                  },
+                  "MultipleChoice": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "selections": {
+                        "type": "object",
+                        "description": "The currently selected values for the component. This can be a literal array of strings or a path to an array in the data model('path', e.g. '/hotel/options').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalArray": {
+                            "type": "array",
+                            "items": {
+                              "type": "string"
+                            }
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "options": {
+                        "type": "array",
+                        "description": "An array of available options for the user to choose from.",
+                        "items": {
+                          "type": "object",
+                          "additionalProperties": false,
+                          "properties": {
+                            "label": {
+                              "type": "object",
+                              "description": "The text to display for this option. This can be a literal string or a reference to a value in the data model (e.g. '/option/label').",
+                              "additionalProperties": false,
+                              "properties": {
+                                "literalString": {
+                                  "type": "string"
+                                },
+                                "path": {
+                                  "type": "string"
+                                }
+                              }
+                            },
+                            "value": {
+                              "type": "string",
+                              "description": "The value to be associated with this option when selected."
+                            }
+                          },
+                          "required": ["label", "value"]
+                        }
+                      },
+                      "maxAllowedSelections": {
+                        "type": "integer",
+                        "description": "The maximum number of options that the user is allowed to select."
+                      }
+                    },
+                    "required": ["selections", "options"]
+                  },
+                  "Slider": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "value": {
+                        "type": "object",
+                        "description": "The current value of the slider. This can be a literal number ('literalNumber') or a reference to a value in the data model ('path', e.g. '/restaurant/cost').",
+                        "additionalProperties": false,
+                        "properties": {
+                          "literalNumber": {
+                            "type": "number"
+                          },
+                          "path": {
+                            "type": "string"
+                          }
+                        }
+                      },
+                      "minValue": {
+                        "type": "number",
+                        "description": "The minimum value of the slider."
+                      },
+                      "maxValue": {
+                        "type": "number",
+                        "description": "The maximum value of the slider."
+                      }
+                    },
+                    "required": ["value"]
+                  }
+                }
+              }
+            },
+            "required": ["id", "component"]
+          }
+        }
+      },
+      "required": ["surfaceId", "components"]
+    },
+    "dataModelUpdate": {
+      "type": "object",
+      "description": "Updates the data model for a surface.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface this data model update applies to."
+        },
+        "path": {
+          "type": "string",
+          "description": "An optional path to a location within the data model (e.g., '/user/name'). If omitted, or set to '/', the entire data model will be replaced."
+        },
+        "contents": {
+          "type": "array",
+          "description": "An array of data entries. Each entry must contain a 'key' and exactly one corresponding typed 'value*' property.",
+          "items": {
+            "type": "object",
+            "description": "A single data entry. Exactly one 'value*' property should be provided alongside the key.",
+            "additionalProperties": false,
+            "properties": {
+              "key": {
+                "type": "string",
+                "description": "The key for this data entry."
+              },
+              "valueString": {
+                "type": "string"
+              },
+              "valueNumber": {
+                "type": "number"
+              },
+              "valueBoolean": {
+                "type": "boolean"
+              },
+              "valueMap": {
+                "description": "Represents a map as an adjacency list.",
+                "type": "array",
+                "items": {
+                  "type": "object",
+                  "description": "One entry in the map. Exactly one 'value*' property should be provided alongside the key.",
+                  "additionalProperties": false,
+                  "properties": {
+                    "key": {
+                      "type": "string"
+                    },
+                    "valueString": {
+                      "type": "string"
+                    },
+                    "valueNumber": {
+                      "type": "number"
+                    },
+                    "valueBoolean": {
+                      "type": "boolean"
+                    }
+                  },
+                  "required": ["key"]
+                }
+              }
+            },
+            "required": ["key"]
+          }
+        }
+      },
+      "required": ["contents", "surfaceId"]
+    },
+    "deleteSurface": {
+      "type": "object",
+      "description": "Signals the client to delete the surface identified by 'surfaceId'.",
+      "additionalProperties": false,
+      "properties": {
+        "surfaceId": {
+          "type": "string",
+          "description": "The unique identifier for the UI surface to be deleted."
+        }
+      },
+      "required": ["surfaceId"]
+    }
+  }
+}

lib/crewai/src/crewai/a2a/extensions/a2ui/schema/v0_8/standard_catalog_definition.json

@@ -0,0 +1,459 @@
+{
+  "components": {
+    "Text": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "text": {
+          "type": "object",
+          "description": "The text content to display. This can be a literal string or a reference to a value in the data model ('path', e.g., '/doc/title'). While simple Markdown formatting is supported (i.e. without HTML, images, or links), utilizing dedicated UI components is generally preferred for a richer and more structured presentation.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "usageHint": {
+          "type": "string",
+          "description": "A hint for the base text style.",
+          "enum": ["h1", "h2", "h3", "h4", "h5", "caption", "body"]
+        }
+      },
+      "required": ["text"]
+    },
+    "Image": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "url": {
+          "type": "object",
+          "description": "The URL of the image to display.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "fit": {
+          "type": "string",
+          "description": "Specifies how the image should be resized to fit its container.",
+          "enum": ["contain", "cover", "fill", "none", "scale-down"]
+        },
+        "usageHint": {
+          "type": "string",
+          "description": "A hint for the image size and style.",
+          "enum": ["icon", "avatar", "smallFeature", "mediumFeature", "largeFeature", "header"]
+        }
+      },
+      "required": ["url"]
+    },
+    "Icon": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "name": {
+          "type": "object",
+          "description": "The name of the icon to display.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": {
+              "type": "string",
+              "enum": [
+                "accountCircle", "add", "arrowBack", "arrowForward", "attachFile",
+                "calendarToday", "call", "camera", "check", "close", "delete",
+                "download", "edit", "event", "error", "favorite", "favoriteOff",
+                "folder", "help", "home", "info", "locationOn", "lock", "lockOpen",
+                "mail", "menu", "moreVert", "moreHoriz", "notificationsOff",
+                "notifications", "payment", "person", "phone", "photo", "print",
+                "refresh", "search", "send", "settings", "share", "shoppingCart",
+                "star", "starHalf", "starOff", "upload", "visibility",
+                "visibilityOff", "warning"
+              ]
+            },
+            "path": { "type": "string" }
+          }
+        }
+      },
+      "required": ["name"]
+    },
+    "Video": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "url": {
+          "type": "object",
+          "description": "The URL of the video to display.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        }
+      },
+      "required": ["url"]
+    },
+    "AudioPlayer": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "url": {
+          "type": "object",
+          "description": "The URL of the audio to be played.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "description": {
+          "type": "object",
+          "description": "A description of the audio, such as a title or summary.",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        }
+      },
+      "required": ["url"]
+    },
+    "Row": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "children": {
+          "type": "object",
+          "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+          "additionalProperties": false,
+          "properties": {
+            "explicitList": { "type": "array", "items": { "type": "string" } },
+            "template": {
+              "type": "object",
+              "additionalProperties": false,
+              "properties": {
+                "componentId": { "type": "string" },
+                "dataBinding": { "type": "string" }
+              },
+              "required": ["componentId", "dataBinding"]
+            }
+          }
+        },
+        "distribution": {
+          "type": "string",
+          "enum": ["center", "end", "spaceAround", "spaceBetween", "spaceEvenly", "start"]
+        },
+        "alignment": {
+          "type": "string",
+          "enum": ["start", "center", "end", "stretch"]
+        }
+      },
+      "required": ["children"]
+    },
+    "Column": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "children": {
+          "type": "object",
+          "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+          "additionalProperties": false,
+          "properties": {
+            "explicitList": { "type": "array", "items": { "type": "string" } },
+            "template": {
+              "type": "object",
+              "additionalProperties": false,
+              "properties": {
+                "componentId": { "type": "string" },
+                "dataBinding": { "type": "string" }
+              },
+              "required": ["componentId", "dataBinding"]
+            }
+          }
+        },
+        "distribution": {
+          "type": "string",
+          "enum": ["start", "center", "end", "spaceBetween", "spaceAround", "spaceEvenly"]
+        },
+        "alignment": {
+          "type": "string",
+          "enum": ["center", "end", "start", "stretch"]
+        }
+      },
+      "required": ["children"]
+    },
+    "List": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "children": {
+          "type": "object",
+          "description": "Defines the children. Use 'explicitList' for a fixed set of children, or 'template' to generate children from a data list.",
+          "additionalProperties": false,
+          "properties": {
+            "explicitList": { "type": "array", "items": { "type": "string" } },
+            "template": {
+              "type": "object",
+              "additionalProperties": false,
+              "properties": {
+                "componentId": { "type": "string" },
+                "dataBinding": { "type": "string" }
+              },
+              "required": ["componentId", "dataBinding"]
+            }
+          }
+        },
+        "direction": {
+          "type": "string",
+          "enum": ["vertical", "horizontal"]
+        },
+        "alignment": {
+          "type": "string",
+          "enum": ["start", "center", "end", "stretch"]
+        }
+      },
+      "required": ["children"]
+    },
+    "Card": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "child": {
+          "type": "string",
+          "description": "The ID of the component to be rendered inside the card."
+        }
+      },
+      "required": ["child"]
+    },
+    "Tabs": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "tabItems": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "title": {
+                "type": "object",
+                "additionalProperties": false,
+                "properties": {
+                  "literalString": { "type": "string" },
+                  "path": { "type": "string" }
+                }
+              },
+              "child": { "type": "string" }
+            },
+            "required": ["title", "child"]
+          }
+        }
+      },
+      "required": ["tabItems"]
+    },
+    "Divider": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "axis": {
+          "type": "string",
+          "enum": ["horizontal", "vertical"]
+        }
+      }
+    },
+    "Modal": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "entryPointChild": {
+          "type": "string",
+          "description": "The ID of the component that opens the modal when interacted with."
+        },
+        "contentChild": {
+          "type": "string",
+          "description": "The ID of the component to be displayed inside the modal."
+        }
+      },
+      "required": ["entryPointChild", "contentChild"]
+    },
+    "Button": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "child": {
+          "type": "string",
+          "description": "The ID of the component to display in the button."
+        },
+        "primary": {
+          "type": "boolean",
+          "description": "Indicates if this button should be styled as the primary action."
+        },
+        "action": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "name": { "type": "string" },
+            "context": {
+              "type": "array",
+              "items": {
+                "type": "object",
+                "additionalProperties": false,
+                "properties": {
+                  "key": { "type": "string" },
+                  "value": {
+                    "type": "object",
+                    "additionalProperties": false,
+                    "properties": {
+                      "path": { "type": "string" },
+                      "literalString": { "type": "string" },
+                      "literalNumber": { "type": "number" },
+                      "literalBoolean": { "type": "boolean" }
+                    }
+                  }
+                },
+                "required": ["key", "value"]
+              }
+            }
+          },
+          "required": ["name"]
+        }
+      },
+      "required": ["child", "action"]
+    },
+    "CheckBox": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "label": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "value": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalBoolean": { "type": "boolean" },
+            "path": { "type": "string" }
+          }
+        }
+      },
+      "required": ["label", "value"]
+    },
+    "TextField": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "label": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "text": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "textFieldType": {
+          "type": "string",
+          "enum": ["date", "longText", "number", "shortText", "obscured"]
+        },
+        "validationRegexp": { "type": "string" }
+      },
+      "required": ["label"]
+    },
+    "DateTimeInput": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "value": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalString": { "type": "string" },
+            "path": { "type": "string" }
+          }
+        },
+        "enableDate": { "type": "boolean" },
+        "enableTime": { "type": "boolean" }
+      },
+      "required": ["value"]
+    },
+    "MultipleChoice": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "selections": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalArray": { "type": "array", "items": { "type": "string" } },
+            "path": { "type": "string" }
+          }
+        },
+        "options": {
+          "type": "array",
+          "items": {
+            "type": "object",
+            "additionalProperties": false,
+            "properties": {
+              "label": {
+                "type": "object",
+                "additionalProperties": false,
+                "properties": {
+                  "literalString": { "type": "string" },
+                  "path": { "type": "string" }
+                }
+              },
+              "value": { "type": "string" }
+            },
+            "required": ["label", "value"]
+          }
+        },
+        "maxAllowedSelections": { "type": "integer" },
+        "variant": {
+          "type": "string",
+          "enum": ["checkbox", "chips"]
+        },
+        "filterable": { "type": "boolean" }
+      },
+      "required": ["selections", "options"]
+    },
+    "Slider": {
+      "type": "object",
+      "additionalProperties": false,
+      "properties": {
+        "value": {
+          "type": "object",
+          "additionalProperties": false,
+          "properties": {
+            "literalNumber": { "type": "number" },
+            "path": { "type": "string" }
+          }
+        },
+        "minValue": { "type": "number" },
+        "maxValue": { "type": "number" }
+      },
+      "required": ["value"]
+    }
+  },
+  "styles": {
+    "font": {
+      "type": "string",
+      "description": "The primary font for the UI."
+    },
+    "primaryColor": {
+      "type": "string",
+      "description": "The primary UI color as a hexadecimal code (e.g., '#00BFFF').",
+      "pattern": "^#[0-9a-fA-F]{6}$"
+    }
+  }
+}

lib/crewai/src/crewai/a2a/extensions/a2ui/server_extension.py

@@ -0,0 +1,125 @@
+"""A2UI server extension for the A2A protocol."""
+
+from __future__ import annotations
+
+import logging
+from typing import Any
+
+from crewai.a2a.extensions.a2ui.models import A2UIResponse, extract_a2ui_json_objects
+from crewai.a2a.extensions.a2ui.validator import (
+    A2UIValidationError,
+    validate_a2ui_message,
+)
+from crewai.a2a.extensions.server import ExtensionContext, ServerExtension
+
+
+logger = logging.getLogger(__name__)
+
+A2UI_MIME_TYPE = "application/json+a2ui"
+A2UI_EXTENSION_URI = "https://a2ui.org/a2a-extension/a2ui/v0.8"
+
+
+class A2UIServerExtension(ServerExtension):
+    """A2A server extension that enables A2UI declarative UI generation.
+
+    When activated by a client that declares A2UI v0.8 support,
+    this extension:
+
+    * Negotiates catalog preferences during ``on_request``.
+    * Wraps A2UI messages in the agent response as A2A DataParts with
+      ``application/json+a2ui`` MIME type during ``on_response``.
+
+    Example::
+
+        A2AServerConfig(
+            server_extensions=[A2UIServerExtension()],
+            default_output_modes=["text/plain", "application/json+a2ui"],
+        )
+    """
+
+    uri: str = A2UI_EXTENSION_URI
+    required: bool = False
+    description: str = "A2UI declarative UI generation"
+
+    def __init__(
+        self,
+        catalog_ids: list[str] | None = None,
+        accept_inline_catalogs: bool = False,
+    ) -> None:
+        """Initialize the A2UI server extension.
+
+        Args:
+            catalog_ids: Catalog identifiers this server supports.
+            accept_inline_catalogs: Whether inline catalog definitions are accepted.
+        """
+        self._catalog_ids = catalog_ids or []
+        self._accept_inline_catalogs = accept_inline_catalogs
+
+    @property
+    def params(self) -> dict[str, Any]:
+        """Extension parameters advertised in the AgentCard."""
+        result: dict[str, Any] = {}
+        if self._catalog_ids:
+            result["supportedCatalogIds"] = self._catalog_ids
+        result["acceptsInlineCatalogs"] = self._accept_inline_catalogs
+        return result
+
+    async def on_request(self, context: ExtensionContext) -> None:
+        """Extract A2UI catalog preferences from the client request.
+
+        Stores the negotiated catalog in ``context.state`` under
+        ``"a2ui_catalog_id"`` for downstream use.
+        """
+        if not self.is_active(context):
+            return
+
+        catalog_id = context.get_extension_metadata(self.uri, "catalogId")
+        if isinstance(catalog_id, str):
+            context.state["a2ui_catalog_id"] = catalog_id
+        elif self._catalog_ids:
+            context.state["a2ui_catalog_id"] = self._catalog_ids[0]
+
+        context.state["a2ui_active"] = True
+
+    async def on_response(self, context: ExtensionContext, result: Any) -> Any:
+        """Wrap A2UI messages in the result as A2A DataParts.
+
+        Scans the result for A2UI JSON payloads and converts them into
+        DataParts with ``application/json+a2ui`` MIME type and A2UI metadata.
+        """
+        if not context.state.get("a2ui_active"):
+            return result
+
+        if not isinstance(result, str):
+            return result
+
+        a2ui_messages = extract_a2ui_json_objects(result)
+        if not a2ui_messages:
+            return result
+
+        data_parts = [
+            part
+            for part in (_build_data_part(msg_data) for msg_data in a2ui_messages)
+            if part is not None
+        ]
+
+        if not data_parts:
+            return result
+
+        return A2UIResponse(text=result, a2ui_parts=data_parts)
+
+
+def _build_data_part(msg_data: dict[str, Any]) -> dict[str, Any] | None:
+    """Validate a single A2UI message and wrap it as a DataPart dict."""
+    try:
+        validated = validate_a2ui_message(msg_data)
+    except A2UIValidationError:
+        logger.warning("Skipping invalid A2UI message in response", exc_info=True)
+        return None
+    return {
+        "kind": "data",
+        "data": validated.model_dump(by_alias=True, exclude_none=True),
+        "metadata": {
+            "mimeType": A2UI_MIME_TYPE,
+        },
+    }

lib/crewai/src/crewai/a2a/extensions/a2ui/validator.py

@@ -0,0 +1,59 @@
+"""Validate A2UI message dicts via Pydantic models."""
+
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import ValidationError
+
+from crewai.a2a.extensions.a2ui.models import A2UIEvent, A2UIMessage
+
+
+class A2UIValidationError(Exception):
+    """Raised when an A2UI message fails validation."""
+
+    def __init__(self, message: str, errors: list[Any] | None = None) -> None:
+        super().__init__(message)
+        self.errors = errors or []
+
+
+def validate_a2ui_message(data: dict[str, Any]) -> A2UIMessage:
+    """Parse and validate an A2UI server-to-client message.
+
+    Args:
+        data: Raw message dict (JSON-decoded).
+
+    Returns:
+        Validated ``A2UIMessage`` instance.
+
+    Raises:
+        A2UIValidationError: If the data does not conform to the A2UI schema.
+    """
+    try:
+        return A2UIMessage.model_validate(data)
+    except ValidationError as exc:
+        raise A2UIValidationError(
+            f"Invalid A2UI message: {exc.error_count()} validation error(s)",
+            errors=exc.errors(),
+        ) from exc
+
+
+def validate_a2ui_event(data: dict[str, Any]) -> A2UIEvent:
+    """Parse and validate an A2UI client-to-server event.
+
+    Args:
+        data: Raw event dict (JSON-decoded).
+
+    Returns:
+        Validated ``A2UIEvent`` instance.
+
+    Raises:
+        A2UIValidationError: If the data does not conform to the A2UI event schema.
+    """
+    try:
+        return A2UIEvent.model_validate(data)
+    except ValidationError as exc:
+        raise A2UIValidationError(
+            f"Invalid A2UI event: {exc.error_count()} validation error(s)",
+            errors=exc.errors(),
+        ) from exc

lib/crewai/src/crewai/a2a/utils/content_type.py

@@ -28,6 +28,7 @@ APPLICATION_PDF: Literal["application/pdf"] = "application/pdf"
 APPLICATION_OCTET_STREAM: Literal["application/octet-stream"] = (
     "application/octet-stream"
 )
+APPLICATION_A2UI_JSON: Literal["application/json+a2ui"] = "application/json+a2ui"
 
 DEFAULT_CLIENT_INPUT_MODES: Final[list[Literal["text/plain", "application/json"]]] = [
     TEXT_PLAIN,
@@ -311,6 +312,10 @@ def get_part_content_type(part: Part) -> str:
     if root.kind == "text":
         return TEXT_PLAIN
     if root.kind == "data":
+        metadata = root.metadata or {}
+        mime = metadata.get("mimeType", "")
+        if mime == APPLICATION_A2UI_JSON:
+            return APPLICATION_A2UI_JSON
         return APPLICATION_JSON
     if root.kind == "file":
         return root.file.mime_type or APPLICATION_OCTET_STREAM

lib/crewai/tests/a2a/extensions/test_a2ui_schema_conformance.py

@@ -0,0 +1,324 @@
+"""Cross-validate A2UI Pydantic models against vendored JSON schemas.
+
+Ensures the two validation sources stay in sync: representative payloads
+must be accepted or rejected consistently by both the Pydantic models and
+the JSON schemas.
+"""
+
+from __future__ import annotations
+
+from typing import Any
+
+import jsonschema
+import pytest
+
+from crewai.a2a.extensions.a2ui.models import A2UIEvent, A2UIMessage
+from crewai.a2a.extensions.a2ui.schema import load_schema
+
+
+SERVER_SCHEMA = load_schema("server_to_client")
+CLIENT_SCHEMA = load_schema("client_to_server")
+CATALOG_SCHEMA = load_schema("standard_catalog_definition")
+
+
+def _json_schema_valid(schema: dict[str, Any], instance: dict[str, Any]) -> bool:
+    """Return True if *instance* validates against *schema*."""
+    try:
+        jsonschema.validate(instance, schema)
+        return True
+    except jsonschema.ValidationError:
+        return False
+
+
+def _pydantic_valid_message(data: dict[str, Any]) -> bool:
+    """Return True if *data* validates as an A2UIMessage."""
+    try:
+        A2UIMessage.model_validate(data)
+        return True
+    except Exception:
+        return False
+
+
+def _pydantic_valid_event(data: dict[str, Any]) -> bool:
+    """Return True if *data* validates as an A2UIEvent."""
+    try:
+        A2UIEvent.model_validate(data)
+        return True
+    except Exception:
+        return False
+
+
+# ---------------------------------------------------------------------------
+# Valid server-to-client payloads
+# ---------------------------------------------------------------------------
+
+VALID_SERVER_MESSAGES: list[dict[str, Any]] = [
+    {
+        "beginRendering": {
+            "surfaceId": "s1",
+            "root": "root-col",
+        },
+    },
+    {
+        "beginRendering": {
+            "surfaceId": "s2",
+            "root": "root-col",
+            "catalogId": "standard (v0.8)",
+            "styles": {"primaryColor": "#FF0000", "font": "Roboto"},
+        },
+    },
+    {
+        "surfaceUpdate": {
+            "surfaceId": "s1",
+            "components": [
+                {
+                    "id": "title",
+                    "component": {
+                        "Text": {"text": {"literalString": "Hello"}},
+                    },
+                },
+            ],
+        },
+    },
+    {
+        "surfaceUpdate": {
+            "surfaceId": "s1",
+            "components": [
+                {
+                    "id": "weighted",
+                    "weight": 2.0,
+                    "component": {
+                        "Column": {
+                            "children": {"explicitList": ["a", "b"]},
+                        },
+                    },
+                },
+            ],
+        },
+    },
+    {
+        "dataModelUpdate": {
+            "surfaceId": "s1",
+            "contents": [
+                {"key": "name", "valueString": "Alice"},
+                {"key": "score", "valueNumber": 42},
+                {"key": "active", "valueBoolean": True},
+            ],
+        },
+    },
+    {
+        "dataModelUpdate": {
+            "surfaceId": "s1",
+            "path": "/user",
+            "contents": [
+                {
+                    "key": "prefs",
+                    "valueMap": [
+                        {"key": "theme", "valueString": "dark"},
+                    ],
+                },
+            ],
+        },
+    },
+    {
+        "deleteSurface": {"surfaceId": "s1"},
+    },
+]
+
+# ---------------------------------------------------------------------------
+# Invalid server-to-client payloads
+# ---------------------------------------------------------------------------
+
+INVALID_SERVER_MESSAGES: list[dict[str, Any]] = [
+    {},
+    {"beginRendering": {"surfaceId": "s1"}},
+    {"surfaceUpdate": {"surfaceId": "s1", "components": []}},
+    {
+        "beginRendering": {"surfaceId": "s1", "root": "r"},
+        "deleteSurface": {"surfaceId": "s1"},
+    },
+    {"unknownType": {"surfaceId": "s1"}},
+]
+
+# ---------------------------------------------------------------------------
+# Valid client-to-server payloads
+# ---------------------------------------------------------------------------
+
+VALID_CLIENT_EVENTS: list[dict[str, Any]] = [
+    {
+        "userAction": {
+            "name": "click",
+            "surfaceId": "s1",
+            "sourceComponentId": "btn-1",
+            "timestamp": "2026-03-12T10:00:00Z",
+            "context": {},
+        },
+    },
+    {
+        "userAction": {
+            "name": "submit",
+            "surfaceId": "s1",
+            "sourceComponentId": "btn-2",
+            "timestamp": "2026-03-12T10:00:00Z",
+            "context": {"field": "value"},
+        },
+    },
+    {
+        "error": {"message": "render failed", "code": 500},
+    },
+]
+
+# ---------------------------------------------------------------------------
+# Invalid client-to-server payloads
+# ---------------------------------------------------------------------------
+
+INVALID_CLIENT_EVENTS: list[dict[str, Any]] = [
+    {},
+    {"userAction": {"name": "click"}},
+    {
+        "userAction": {
+            "name": "click",
+            "surfaceId": "s1",
+            "sourceComponentId": "btn-1",
+            "timestamp": "2026-03-12T10:00:00Z",
+            "context": {},
+        },
+        "error": {"message": "oops"},
+    },
+]
+
+# ---------------------------------------------------------------------------
+# Catalog component payloads (validated structurally)
+# ---------------------------------------------------------------------------
+
+VALID_COMPONENTS: dict[str, dict[str, Any]] = {
+    "Text": {"text": {"literalString": "hello"}, "usageHint": "h1"},
+    "Image": {"url": {"path": "/img/url"}, "fit": "cover", "usageHint": "avatar"},
+    "Icon": {"name": {"literalString": "home"}},
+    "Video": {"url": {"literalString": "https://example.com/video.mp4"}},
+    "AudioPlayer": {"url": {"literalString": "https://example.com/audio.mp3"}},
+    "Row": {"children": {"explicitList": ["a", "b"]}, "distribution": "center"},
+    "Column": {"children": {"template": {"componentId": "c1", "dataBinding": "/list"}}},
+    "List": {"children": {"explicitList": ["x"]}, "direction": "horizontal"},
+    "Card": {"child": "inner"},
+    "Tabs": {"tabItems": [{"title": {"literalString": "Tab 1"}, "child": "content"}]},
+    "Divider": {"axis": "horizontal"},
+    "Modal": {"entryPointChild": "trigger", "contentChild": "body"},
+    "Button": {"child": "label", "action": {"name": "go"}},
+    "CheckBox": {"label": {"literalString": "Accept"}, "value": {"literalBoolean": False}},
+    "TextField": {"label": {"literalString": "Name"}},
+    "DateTimeInput": {"value": {"path": "/date"}},
+    "MultipleChoice": {
+        "selections": {"literalArray": ["a"]},
+        "options": [{"label": {"literalString": "A"}, "value": "a"}],
+    },
+    "Slider": {"value": {"literalNumber": 50}, "minValue": 0, "maxValue": 100},
+}
+
+
+class TestServerToClientConformance:
+    """Pydantic models and JSON schema must agree on server-to-client messages."""
+
+    @pytest.mark.parametrize("payload", VALID_SERVER_MESSAGES)
+    def test_valid_accepted_by_both(self, payload: dict[str, Any]) -> None:
+        assert _json_schema_valid(SERVER_SCHEMA, payload), (
+            f"JSON schema rejected valid payload: {payload}"
+        )
+        assert _pydantic_valid_message(payload), (
+            f"Pydantic rejected valid payload: {payload}"
+        )
+
+    @pytest.mark.parametrize("payload", INVALID_SERVER_MESSAGES)
+    def test_invalid_rejected_by_pydantic(self, payload: dict[str, Any]) -> None:
+        assert not _pydantic_valid_message(payload), (
+            f"Pydantic accepted invalid payload: {payload}"
+        )
+
+
+class TestClientToServerConformance:
+    """Pydantic models and JSON schema must agree on client-to-server events."""
+
+    @pytest.mark.parametrize("payload", VALID_CLIENT_EVENTS)
+    def test_valid_accepted_by_both(self, payload: dict[str, Any]) -> None:
+        assert _json_schema_valid(CLIENT_SCHEMA, payload), (
+            f"JSON schema rejected valid payload: {payload}"
+        )
+        assert _pydantic_valid_event(payload), (
+            f"Pydantic rejected valid payload: {payload}"
+        )
+
+    @pytest.mark.parametrize("payload", INVALID_CLIENT_EVENTS)
+    def test_invalid_rejected_by_pydantic(self, payload: dict[str, Any]) -> None:
+        assert not _pydantic_valid_event(payload), (
+            f"Pydantic accepted invalid payload: {payload}"
+        )
+
+
+class TestCatalogConformance:
+    """Catalog component schemas and Pydantic models must define the same components."""
+
+    def test_catalog_component_names_match(self) -> None:
+        from crewai.a2a.extensions.a2ui.catalog import STANDARD_CATALOG_COMPONENTS
+
+        schema_components = set(CATALOG_SCHEMA["components"].keys())
+        assert schema_components == STANDARD_CATALOG_COMPONENTS
+
+    @pytest.mark.parametrize(
+        "name,props",
+        list(VALID_COMPONENTS.items()),
+    )
+    def test_valid_component_accepted_by_catalog_schema(
+        self, name: str, props: dict[str, Any]
+    ) -> None:
+        component_schema = CATALOG_SCHEMA["components"][name]
+        assert _json_schema_valid(component_schema, props), (
+            f"Catalog schema rejected valid {name}: {props}"
+        )
+
+    @pytest.mark.parametrize(
+        "name,props",
+        list(VALID_COMPONENTS.items()),
+    )
+    def test_valid_component_accepted_by_pydantic(
+        self, name: str, props: dict[str, Any]
+    ) -> None:
+        import crewai.a2a.extensions.a2ui.catalog as catalog_mod
+
+        model_cls = getattr(catalog_mod, name)
+        try:
+            model_cls.model_validate(props)
+        except Exception as exc:
+            pytest.fail(f"Pydantic {name} rejected valid props: {exc}")
+
+    def test_catalog_required_fields_match(self) -> None:
+        """Required fields in the JSON schema match non-optional Pydantic fields."""
+        import crewai.a2a.extensions.a2ui.catalog as catalog_mod
+
+        for comp_name, comp_schema in CATALOG_SCHEMA["components"].items():
+            schema_required = set(comp_schema.get("required", []))
+            model_cls = getattr(catalog_mod, comp_name)
+            pydantic_required = {
+                info.alias or field_name
+                for field_name, info in model_cls.model_fields.items()
+                if info.is_required()
+            }
+            assert schema_required == pydantic_required, (
+                f"{comp_name}: schema requires {schema_required}, "
+                f"Pydantic requires {pydantic_required}"
+            )
+
+    def test_catalog_fields_match(self) -> None:
+        """Field names in JSON schema match Pydantic model aliases."""
+        import crewai.a2a.extensions.a2ui.catalog as catalog_mod
+
+        for comp_name, comp_schema in CATALOG_SCHEMA["components"].items():
+            schema_fields = set(comp_schema.get("properties", {}).keys())
+            model_cls = getattr(catalog_mod, comp_name)
+            pydantic_fields = {
+                info.alias or field_name
+                for field_name, info in model_cls.model_fields.items()
+            }
+            assert schema_fields == pydantic_fields, (
+                f"{comp_name}: schema has {schema_fields}, "
+                f"Pydantic has {pydantic_fields}"
+            )