Archive
An MCP control plane is the layer that decides which agent may call which tool, on which server, under which conditions — separated from the servers that execute the calls. Definition, architecture, and when you need one.
Read the guide →Four categories of MCP gateway, twelve evaluation criteria with five outright disqualifiers, a scoring worksheet, and an honest statement of where Barzel Central Gateway fits and where it does not.
Read the guide →How to build an MCP capability graph: the four node types and three edge types, the five questions only a graph answers, how it exposes duplicate tools and single points of failure, and how to keep it current.
Read the guide →What to instrument in an MCP estate: the twelve fields on every tool-call span, the six metrics worth alerting on, why refusal rate is the most useful signal you have, and the three dashboards that get read.
Read the guide →A five-class risk scheme for MCP tools that engineers will actually apply: the two questions that drive it, why parameter values change the class, how to score a tool you did not write, and what each class entitles.
Read the guide →How an MCP policy engine works: the ten inputs a decision needs, four outcomes richer than allow/deny, why policy must be deterministic, shadow mode, and how to test rules before they touch production.
Read the guide →How MCP tool routing works when several servers can serve the same capability: six routing signals worth using, three that sound clever, fallback design, and why routing decisions belong in the audit record.
Read the guide →How MCP tool discovery works, why a flat tools/list stops scaling past roughly 40 tools, and the four patterns — filtering, progressive disclosure, semantic retrieval and namespacing — that fix selection accuracy and token cost together.
Read the guide →How to build an internal MCP registry: the approval states every entry needs, the twelve-field record, intake and deprecation, and why a registry without an enforcement point is a wiki page.
Read the guide →How to inventory MCP servers across an enterprise: six discovery sources, the eleven fields every entry needs, how to find unowned servers, and how to keep the inventory current after week one.
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