Projections And Round Trips

Human Review Surface

In Zerolang, .0 files are human-readable projections of the graph.

They exist for trust. A human can read the program, review a change, and make a manual edit when needed. They are also useful for diagnostics because source maps can point to familiar line and column spans.

They are not the normal agent write surface.

Explicit Sync Model

Zero uses explicit commands so graph and projection state cannot silently drift:

zero export
zero import
zero verify-projection
zero status

Use zero export when a human needs the latest .0 review text. Use zero import after a human intentionally edits projection text and wants to reconstruct the graph. Use zero verify-projection in review or CI when you want a no-write drift check.

No Silent Divergence

zero status reports whether the projection is clean, missing, stale, conflicting, or unavailable. When the checked-in .0 sources were edited after zero.graph was written, commands that consume the store, including zero check, zero build, zero run, zero test, zero query, zero view, and zero diff, refresh the store from the edited source first and report the refresh on stderr. When the graph is the newer side, for example right after zero patch, those commands keep using zero.graph until zero export syncs the projection, and they say so on stderr. When both sides were edited independently, they fail with an RGP006 diagnostic that offers zero import and zero export as repairs instead of picking a side. Which side moved is decided by content: every store write records a hash of the source projection inside zero.graph, so a freshly staged, cloned, or extracted workspace classifies the same way everywhere regardless of file timestamps. Set ZERO_STALE=fail to fail with an RGP008 diagnostic instead of refreshing automatically.

That rule prevents the worst ambiguity: an agent editing text, seeing zero check pass, and then running a binary built from different code.

Human Escape Hatch

The escape hatch is deliberate. A project should remain reconstructable from text projections. A human can edit src/main.0, reconcile it back into the graph, and confirm the projection still matches:

This keeps the system auditable. The graph is first-class, but humans are not locked out of a readable format.

Review Rule

Use graph commands for authoring. Use projections for review. Import projections only when a human intentionally edits them.