Machine Readable Capability Registry System

via “capability registry with pluggable loaders and discovery”

[Python MCP SDK](https://github.com/modelcontextprotocol/python-sdk)

Unique: Implements a pluggable loader architecture where ArrayLoader handles manual registration and Discoverer handles attribute-based auto-discovery, with the Registry merging results into a unified namespace. This enables hybrid approaches where capabilities come from multiple sources without code duplication.

vs others: More modular than monolithic registry approaches because loaders are composable and can be extended independently, supporting both declarative (attributes) and imperative (manual) capability registration patterns.