Add Support for Agntcy/SLIM

[destroyersrt]

Add SLIM Protocol Support with Modular Protocol Architecture

Description

Add support for Cisco AGNTCY's SLIM (Secure Low-latency Interactive Messaging) protocol while implementing a modular protocol abstraction layer. This enables NEST agents to communicate via SLIM's gRPC-based, quantum-safe messaging while allowing future protocol additions (A2A, MCP, custom protocols) without core code changes.

The @agent-id routing mechanism will remain unchanged - it discovers agents via NANDA Index and automatically selects the appropriate protocol based on the target agent's capabilities.

SLIM natively supports unicast, anycast, and multicast communication patterns - design should accommodate these patterns for multi-agent coordination scenarios.

Implementation Approach

• Create AgentProtocol abstract interface with send(), receive(), get_routes() methods
• Implement SLIMProtocol adapter with gRPC client integration
• Build ProtocolRouter to manage protocol registration and message routing
• Update handle_message() to use protocol router for @mention resolution
• Extend AgentFacts schema with supported_protocols and protocol-specific endpoints
• Add config-driven protocol enablement
• Design protocol interface to support unicast, multicast, and broadcast patterns

Acceptance Criteria

• AgentProtocol abstract base class created with support for different messaging patterns
• SLIMProtocol implementation with gRPC client
• ProtocolRouter manages protocol registration and routing
• Agents can send messages via SLIM using existing @agent-id syntax
• AgentFacts includes supported_protocols: ["slim"] and endpoints.slim
• Config file allows enabling/disabling SLIM via protocols.slim.enabled
• Protocol auto-detection works: discovers agent → checks supported protocols → routes via SLIM
• Design considers multicast/broadcast patterns (implementation can be future work)
• New protocols can be added by implementing AgentProtocol interface without modifying core
• Documentation for adding custom protocol adapters
• Tests for SLIM message sending/receiving and protocol routing

References

• SLIM Protocol
• AGNTCY Docs