Federation

Synth federates via the signals-protocol (components/signals-protocol), never via direct integration with peer engines’ native surfaces.

The core law (learned 2026-07-03, first live cross-engine call): gRPC method paths embed package+service, so a wire-identical peer still returns UNIMPLEMENTED if only the native service is registered. Therefore serve() registers both servicers on one port:

• synth.engine.SynthEngine — the native, project-internal surface (src/synth/engine/proto/synth_engine.proto);
• zndx.engine.v1.Engine — the shared federation face (Complete / Status / Remediate).

Shared-host lattice

Ratifying synth’s row in the signals-protocol adopters table is a pending follow-up (additive change to the submodule’s spec, PR’d upstream).

GPU co-tenancy uses the advisory lease directory /tmp/zndx-gpu-leases; capability requests are forwarded to peers in preference to moving GPUs.