A fresh coding agent explores your repo for 30 turns and $1.31 before it can answer a question. The next agent does it again. And again. This talk demonstrates a context registry that breaks the cycle: Agent A explores, writes architecture docs, conventions, and a handoff note to a shared MCP capsule. Agent B starts fresh, calls one tool, reads the capsule, and answers in 5 turns for $0.16 — an 87.6% reduction in model cost. We show the Time Traveler demo live, explain the URI-schemed context model that makes stored knowledge inspectable and versionable, and present the research methodology behind the cost claims including caveats about break-even thresholds and model-specific variation. The audience leaves with a running self-hosted registry they can try in five minutes.