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

[butok]

Hi @dpiskula-nxp.
nxp-upstream/zephyr does not accept PRs.
Please close the Pull Request and submit it to the zephyrproject-rtos/zephyr repository.

[dpiskula-nxp]

Hi @dpiskula-nxp. nxp-upstream/zephyr does not accept PRs. Please close the Pull Request and submit it to the zephyrproject-rtos/zephyr repository.

Hello @butok, this is a development PR from a dev sub-branch (mcp-core) into our dev main-branch (mcp-server). The PR into the main upstream branch will be opened properly when ready.

Since we are developing a library and need to collaborate by developing different parts in paralel, I wanted to split development into these sub-branches and merge them into the main dev branch through our own PRs. I realize this is not commonly done on the nxp repository but I don't see any other way of doing it except for developing on an internal repository outside GitHub, which would just complicate things unnecessarily.