# Phase 3 shipped: Immutable template sources

> Local and Git-subdirectory template sources can be locked, materialized, verified by digest, and checked for drift.


Phase 3 introduced the immutable template boundary consumed by every lifecycle
operation.

## What shipped

- Local and Git-subdirectory source resolution.
- Canonical lock records with immutable revisions and tree digests.
- Contained, private template materialization and verified cache reuse.
- Explicit source updates with visible changes.
- Deterministic source, lock, digest, and cache drift diagnostics.

Read the complete
[Phase 3 development note](https://github.com/projectious-work/ainfra/blob/v1.x-dev/dev-notes/phase-03-immutable-template-sources.md)
or inspect
[v1.0.0-alpha.3](https://github.com/projectious-work/ainfra/releases/tag/v1.0.0-alpha.3).


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Source: https://projectious-work.github.io/ainfra/changelog/phase-3-immutable-template-sources-shipped/index.md