ACP sits above MCP as an intent-resolution layer. Send intent, get back a scoped manifest: only relevant tools, auth injected server-side (never in context), execution ordering declared. Benchmark results (50 runs/scenario, tiktoken cl100k_base): • 373 → 111 tokens (-70%) for a standard query • 9,223 → 241 tokens (-97.4%) with 50 tools, 2 relevant • 1,431 → 359 tokens (-74.9%)