# Why one gateway and not eleven servers

> Decision E16: domain servers behind one gateway, two-stage discovery, one place for policy.


The platform offers its tools through a gateway with one server per domain behind it. Other layouts were examined and rejected.

## Rejected {#verworfen}

- **Eleven single servers without a gateway.** A foreign agent would have to configure eleven connections and would see up to 165 tools in aggregate.
- **Two or three bundles, or a monolith.** The GitHub precedent: 101 tools in one server lowered tool-selection accuracy from 95 to 71 percent.

## Decided {#entschieden}

One MCP server per domain with three to fifteen tools, its own auth boundary and its own directory entry; mini domains live as a namespace in a closely related server. The primary machine access is the gateway, one component with two functions: policy (authentication, rate limits, session budget) and aggregation (flat names `<domain>.<verb_object>`, deterministic tool list, two-stage discovery that loads only the three to five relevant schemas).

## What follows {#folgen}

Policy happens exactly once, whichever door a call comes through. An agent first reads 52 one-liners and then loads only the schemas it needs. And every domain can one day appear as a directory entry of its own, through the same admission route as everyone else.

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Source: docs/en/explanation/why-a-gateway.md