MCP Core implementation - Initialization, Tools/List, Tools/Call (Missing Health monitor and tool cancellation)

[dpiskula-nxp]

Intermediary PR containing a partial working implementation of the MCP core with the following features:

Core Infrastructure

• Multi-threaded request processing with configurable worker pools
• Message queue-based communication between transport and server layers (transport side is mocked in a very trivial way)
• Server initialization and startup lifecycle management

Client Management

• Client registration/deregistration and connection lifecycle tracking
• State machine enforcement (DEINITIALIZED → NEW → INITIALIZING → INITIALIZED → DEINITIALIZING → DEINITIALIZED)

Protocol Support

• MCP initialization handshake with capability negotiation
• Initialize request/response processing
• System message processing for client shutdown to enable client registry clean up (used by unit tests only, for now)
• Tools/list request handling implemented
• Tools/call request handling implemented

Tool Management

• Tool registration and removal

Message Processing

• Request type routing and dispatching
• Response queuing to transport layer (mocked)
• Error handling and cleanup for failed operations

Testing

• Basic unit tests for client lifecycle and tool management

Currently Missing/TODO

• Tool cancellation
• The library uses dynamic memory allocation abstracted through mcp_alloc/mcp_free – optimizations through static allocation/memory slabs are to be considered
• MCP Core health monitor