Chapter 10 - The Nervous System: MCP and Protocol Interop
Last updated 2026-07-13. Review the protocol-side primary sources behind Chapter 10 and explore the live MCP server catalog for current implementations.
Companion activity
Use the MCP catalog to evaluate one server by asking what it exposes, who authorizes it, what gets logged, and what judgment still lives outside the protocol.
What this chapter argues
MCP - the Model Context Protocol - is one exchange layer through which AI applications can discover and invoke tools or access context. It does not create judgment, governance, security, or learning on its own. The nervous-system analogy is useful but limited: hosts and implementations still decide what is exposed, authorized, logged, reviewed, and retained. A defensible decision record therefore depends on explicit logging and decision context around tool use, not on protocol traffic alone.
Key sources
Chapter 10 cites in the print book: D6, D61, D62, D63. Entries below are the sources this page draws on; some are related literature cited elsewhere in the book rather than in this chapter.
- D6 - Anthropic. (2024). Introducing the Model Context Protocol. anthropic.com/news/model-context-protocol
- D12 - OpenAI. (2023). Function calling and other API updates. openai.com/index/function-calling-and-other-api-updates/
Primary-source links
- Anthropic, "Introducing the Model Context Protocol" (November 25, 2024) - the launch announcement and the spec's authoritative starting point.
- OpenAI, "Function calling and other API updates" (June 2023) - the predecessor pattern that established the tool-use call format MCP later generalized into a vendor-neutral protocol.
Chapter contents
- What MCP is and what it is not (a transport, not a model; infrastructure, not computation).
- Why a protocol layer matters - the spinal-cord analog explained.
- The defensibility implication: tool calls in the audit trail give post-hoc decision reconstruction.
- Interop with the function-calling lineage and where MCP diverges.
Live MCP catalog
The current MCP server catalog - which vendors implement what, with which capabilities, and which client surfaces consume it - lives at /mcp/. Each entry carries a verified date. Refreshed quarterly.