# Nexus ↔ Frames Synchronization Policy

## Canonical ownership

The standalone Nexus source is canonical. Frames consumes immutable Nexus versions and must not maintain a private compiler fork.

## Required change flow

1. Make a Nexus fix/feature in canonical Nexus source.
2. Run the Nexus release gate.
3. Assign a new immutable Nexus version whenever canonical compiler/toolchain source changes.
4. Seal the canonical source tree/archive and checksum it.
5. Synchronize that exact version into Frames.
6. Record the version/tree checksum in `Frames/toolchain/NEXUS-PIN.json`.
7. Run Frames build/runtime certification against that pin.

An urgent Frames-discovered compiler defect still belongs in Nexus first, then flows back into Frames.

## Version rule

Published versions are immutable. A fix after 6.0.0 is 6.0.1 (or the next appropriate version), never a rewritten 6.0.0.