Build a Multimodal Agentic RAG App with Gemini Embedding 2 and Google ADK
Summary
This tutorial details the construction of a multimodal agentic RAG application utilizing Gemini Embedding 2 and the Google Agent Development Kit (ADK). The application integrates text, URLs, PDFs, images, audio, and video into a single 768-dimension embedding space, enabling unified retrieval. Gemini Embedding 2 handles the embedding of diverse modalities, employing task prefixes like "task: retrieval document" and "task: question answering | query" to enhance retrieval quality. The Google ADK agent coordinates retrieval and synthesizes grounded, cited answers. Key features include a truly multimodal index, a single retrieval packet consumed by both the agent and the UI for consistent citations, and a 3D PCA embedding view. The backend is implemented with FastAPI, Python 3.12, and requires a Gemini API key.
Key takeaway
For AI Engineers building RAG applications that handle diverse data types, this architecture provides a robust, open-source blueprint. You should consider adopting Gemini Embedding 2 for its multimodal capabilities and Google ADK for agentic coordination to ensure consistent, grounded answers and citations across text, images, audio, and video. This approach simplifies pipeline complexity by unifying embedding spaces and retrieval logic.
Key insights
Gemini Embedding 2 and Google ADK enable unified multimodal RAG with consistent citations across diverse data types.
Principles
- Blend media and text vectors for improved file search.
- Use task prefixes for better embedding retrieval.
- Single retrieval contract ensures citation consistency.
Method
Sources are chunked and embedded with Gemini Embedding 2 using task prefixes. Queries are embedded, and cosine similarity ranks chunks. A Google ADK agent then uses the retrieved context to generate a grounded answer, ensuring the UI and agent share the same retrieval packet.
In practice
- Implement SSRF protection for URL ingestion.
- Offload blocking calls to a threadpool for responsiveness.
- Delete uploaded files via Gemini File API in a finally block.
Topics
- Multimodal RAG
- Gemini Embedding 2
- Google ADK
- ADK Agent
- Multimodal Embeddings
Code references
Best for: AI Engineer, Machine Learning Engineer, Software Engineer
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Editorial summary, takeaway, and curation by AIssential. Original article published by unwind ai.