Add A2A (Agent-to-Agent) Protocol Support to Registry #195
Description
Overview
Enable the MCP Gateway Registry to serve as a curated registry for A2A (Agent-to-Agent) protocol, allowing agents to discover and communicate with other agents while maintaining enterprise security and governance.
Current State
Registry currently manages MCP servers (tools). No agent discovery or management.
Requirements
Core Functionality
- Agent Card Registry: Store and manage A2A Agent Cards following the A2A protocol specification
- Agent Discovery: Find agents by skills, capabilities, and tags using semantic search
- CRUD Operations: Register, update, retrieve, and delete agent cards
- Access Control: Fine-grained authorization using existing Keycloak/OAuth2 infrastructure
Architecture
- Registry-Only: Agents discover other agents through the registry but communicate directly (P2P)
- Separate API Namespace:
/api/agents/*endpoints (distinct from/api/servers/*) - Unified Search: Extend existing FAISS-based semantic search for both MCP servers and agents
- Authentication: Keycloak controls registry access; agents define their own security schemes
- No Breaking Changes: Existing MCP functionality completely unchanged
Design Document
See .scratchpad/a2a-integration-design.md for detailed architecture, data models, and API specifications.
Key Design Decisions
- Registry API is custom - A2A spec does not define registry standards (implementation-specific)
- Keycloak for registry access - Agent-to-agent auth is separate (agents handle their own)
- Direct P2P communication - Registry returns URLs only, doesn't route traffic
- Minimal new modules - Reuse existing auth, search, storage patterns
Acceptance Criteria
- Agent Card data models implemented (Pydantic)
- CRUD endpoints implemented
- Discovery/search endpoints working
- Authorization working (Keycloak integration)
- Tests passing
- Design document finalized in docs/design/
Related
- A2A Protocol: https://a2a-protocol.org/
- Design Reference:
.scratchpad/a2a-integration-design.md