feat(blocks): Add Bannerbear API block for text overlay on images (#10768)

## Summary
- Implemented a new Bannerbear API block that enables adding text
overlays to images using template designs
- Block supports customizable text styling (color, font, size, weight,
alignment)
- Always uses synchronous API mode for immediate image generation
results


[agent_ead942d9-58a2-4be6-bdb3-99010c489466.json](https://github.com/user-attachments/files/22027352/agent_ead942d9-58a2-4be6-bdb3-99010c489466.json)

<img width="140" height="572" alt="Screenshot 2025-08-28 at 16 28 35"
src="https://github.com/user-attachments/assets/096b532b-31dc-4ca6-bd68-c00b7594426c"
/>


## Features
- **Text overlay capabilities**: Add multiple text layers to images
using Bannerbear templates
- **Customizable styling**: Support for color, font family, font size,
font weight, and text alignment
- **Image support**: Optional ability to add images to templates
- **Smart field handling**: Only sends non-empty optional parameters to
the API
- **Webhook & metadata**: Advanced options for webhook notifications and
custom metadata

## Implementation Details
- Created provider configuration with API key authentication
- Implemented `BannerbearTextOverlayBlock` with proper input/output
schemas
- Extracted API calls to private method `_make_api_request()` for test
mocking support
- Follows SDK guide patterns and integrates with AutoGPT platform

## Use Case
This block will be used in the Ad generator agent for creating dynamic
marketing materials and social media graphics with text overlays.

## Test plan
- [x] Block imports successfully
- [x] Block instantiates with unique ID
- [x] Code passes linting and formatting checks
- [x] Manual testing with actual Bannerbear API key
- [x] Integration testing with Ad generator agent

autogpt_platform/backend/backend/blocks/bannerbear/__init__.py

@@ -0,0 +1,3 @@
+from .text_overlay import BannerbearTextOverlayBlock
+
+__all__ = ["BannerbearTextOverlayBlock"]

autogpt_platform/backend/backend/blocks/bannerbear/_config.py

@@ -0,0 +1,8 @@
+from backend.sdk import BlockCostType, ProviderBuilder
+
+bannerbear = (
+    ProviderBuilder("bannerbear")
+    .with_api_key("BANNERBEAR_API_KEY", "Bannerbear API Key")
+    .with_base_cost(1, BlockCostType.RUN)
+    .build()
+)

autogpt_platform/backend/backend/blocks/bannerbear/text_overlay.py

@@ -0,0 +1,239 @@
+import uuid
+from typing import TYPE_CHECKING, Any, Dict, List
+
+if TYPE_CHECKING:
+    pass
+
+from pydantic import SecretStr
+
+from backend.sdk import (
+    APIKeyCredentials,
+    Block,
+    BlockCategory,
+    BlockOutput,
+    BlockSchema,
+    CredentialsMetaInput,
+    Requests,
+    SchemaField,
+)
+
+from ._config import bannerbear
+
+TEST_CREDENTIALS = APIKeyCredentials(
+    id="01234567-89ab-cdef-0123-456789abcdef",
+    provider="bannerbear",
+    api_key=SecretStr("mock-bannerbear-api-key"),
+    title="Mock Bannerbear API Key",
+)
+
+
+class TextModification(BlockSchema):
+    name: str = SchemaField(
+        description="The name of the layer to modify in the template"
+    )
+    text: str = SchemaField(description="The text content to add to this layer")
+    color: str = SchemaField(
+        description="Hex color code for the text (e.g., '#FF0000')",
+        default="",
+        advanced=True,
+    )
+    font_family: str = SchemaField(
+        description="Font family to use for the text",
+        default="",
+        advanced=True,
+    )
+    font_size: int = SchemaField(
+        description="Font size in pixels",
+        default=0,
+        advanced=True,
+    )
+    font_weight: str = SchemaField(
+        description="Font weight (e.g., 'bold', 'normal')",
+        default="",
+        advanced=True,
+    )
+    text_align: str = SchemaField(
+        description="Text alignment (left, center, right)",
+        default="",
+        advanced=True,
+    )
+
+
+class BannerbearTextOverlayBlock(Block):
+    class Input(BlockSchema):
+        credentials: CredentialsMetaInput = bannerbear.credentials_field(
+            description="API credentials for Bannerbear"
+        )
+        template_id: str = SchemaField(
+            description="The unique ID of your Bannerbear template"
+        )
+        project_id: str = SchemaField(
+            description="Optional: Project ID (required when using Master API Key)",
+            default="",
+            advanced=True,
+        )
+        text_modifications: List[TextModification] = SchemaField(
+            description="List of text layers to modify in the template"
+        )
+        image_url: str = SchemaField(
+            description="Optional: URL of an image to use in the template",
+            default="",
+            advanced=True,
+        )
+        image_layer_name: str = SchemaField(
+            description="Optional: Name of the image layer in the template",
+            default="photo",
+            advanced=True,
+        )
+        webhook_url: str = SchemaField(
+            description="Optional: URL to receive webhook notification when image is ready",
+            default="",
+            advanced=True,
+        )
+        metadata: str = SchemaField(
+            description="Optional: Custom metadata to attach to the image",
+            default="",
+            advanced=True,
+        )
+
+    class Output(BlockSchema):
+        success: bool = SchemaField(
+            description="Whether the image generation was successfully initiated"
+        )
+        image_url: str = SchemaField(
+            description="URL of the generated image (if synchronous) or placeholder"
+        )
+        uid: str = SchemaField(description="Unique identifier for the generated image")
+        status: str = SchemaField(description="Status of the image generation")
+        error: str = SchemaField(description="Error message if the operation failed")
+
+    def __init__(self):
+        super().__init__(
+            id="c7d3a5c2-05fc-450e-8dce-3b0e04626009",
+            description="Add text overlay to images using Bannerbear templates. Perfect for creating social media graphics, marketing materials, and dynamic image content.",
+            categories={BlockCategory.PRODUCTIVITY, BlockCategory.AI},
+            input_schema=self.Input,
+            output_schema=self.Output,
+            test_input={
+                "template_id": "jJWBKNELpQPvbX5R93Gk",
+                "text_modifications": [
+                    {
+                        "name": "headline",
+                        "text": "Amazing Product Launch!",
+                        "color": "#FF0000",
+                    },
+                    {
+                        "name": "subtitle",
+                        "text": "50% OFF Today Only",
+                    },
+                ],
+                "credentials": {
+                    "provider": "bannerbear",
+                    "id": str(uuid.uuid4()),
+                    "type": "api_key",
+                },
+            },
+            test_output=[
+                ("success", True),
+                ("image_url", "https://cdn.bannerbear.com/test-image.jpg"),
+                ("uid", "test-uid-123"),
+                ("status", "completed"),
+            ],
+            test_mock={
+                "_make_api_request": lambda *args, **kwargs: {
+                    "uid": "test-uid-123",
+                    "status": "completed",
+                    "image_url": "https://cdn.bannerbear.com/test-image.jpg",
+                }
+            },
+            test_credentials=TEST_CREDENTIALS,
+        )
+
+    async def _make_api_request(self, payload: dict, api_key: str) -> dict:
+        """Make the actual API request to Bannerbear. This is separated for easy mocking in tests."""
+        headers = {
+            "Authorization": f"Bearer {api_key}",
+            "Content-Type": "application/json",
+        }
+
+        response = await Requests().post(
+            "https://sync.api.bannerbear.com/v2/images",
+            headers=headers,
+            json=payload,
+        )
+
+        if response.status in [200, 201, 202]:
+            return response.json()
+        else:
+            error_msg = f"API request failed with status {response.status}"
+            if response.text:
+                try:
+                    error_data = response.json()
+                    error_msg = (
+                        f"{error_msg}: {error_data.get('message', response.text)}"
+                    )
+                except Exception:
+                    error_msg = f"{error_msg}: {response.text}"
+            raise Exception(error_msg)
+
+    async def run(
+        self, input_data: Input, *, credentials: APIKeyCredentials, **kwargs
+    ) -> BlockOutput:
+        # Build the modifications array
+        modifications = []
+
+        # Add text modifications
+        for text_mod in input_data.text_modifications:
+            mod_data: Dict[str, Any] = {
+                "name": text_mod.name,
+                "text": text_mod.text,
+            }
+
+            # Add optional text styling parameters only if they have values
+            if text_mod.color and text_mod.color.strip():
+                mod_data["color"] = text_mod.color
+            if text_mod.font_family and text_mod.font_family.strip():
+                mod_data["font_family"] = text_mod.font_family
+            if text_mod.font_size and text_mod.font_size > 0:
+                mod_data["font_size"] = text_mod.font_size
+            if text_mod.font_weight and text_mod.font_weight.strip():
+                mod_data["font_weight"] = text_mod.font_weight
+            if text_mod.text_align and text_mod.text_align.strip():
+                mod_data["text_align"] = text_mod.text_align
+
+            modifications.append(mod_data)
+
+        # Add image modification if provided and not empty
+        if input_data.image_url and input_data.image_url.strip():
+            modifications.append(
+                {
+                    "name": input_data.image_layer_name,
+                    "image_url": input_data.image_url,
+                }
+            )
+
+        # Build the request payload - only include non-empty optional fields
+        payload = {
+            "template": input_data.template_id,
+            "modifications": modifications,
+        }
+
+        # Add project_id if provided (required for Master API keys)
+        if input_data.project_id and input_data.project_id.strip():
+            payload["project_id"] = input_data.project_id
+
+        if input_data.webhook_url and input_data.webhook_url.strip():
+            payload["webhook_url"] = input_data.webhook_url
+        if input_data.metadata and input_data.metadata.strip():
+            payload["metadata"] = input_data.metadata
+
+        # Make the API request using the private method
+        data = await self._make_api_request(
+            payload, credentials.api_key.get_secret_value()
+        )
+
+        # Synchronous request - image should be ready
+        yield "success", True
+        yield "image_url", data.get("image_url", "")
+        yield "uid", data.get("uid", "")
+        yield "status", data.get("status", "completed")