# Versions and Branches

Lob's own branch and merge model is still being defined (see [Merge Conflicts](/docs/compare-and-morph/merge-conflicts)) - this page covers how Tensormorph addresses a version today, not a confirmed branching UI.

Tensormorph doesn't store weight history itself - that's Lob's job, as an external, separate system. What Tensormorph does is address a specific version precisely, and detect when that address has gone stale.

## Commit pins and stale-notes

A checkpoint loaded through Lob carries a **commit pin**: a reference to the exact Lob commit and content hash it was materialized from. If Lob's history moves past that pin, Tensormorph flags a **stale-note** rather than silently comparing you against outdated history - the same mechanism described in [Merge Conflicts](/docs/compare-and-morph/merge-conflicts#how-tensormorph-anchors-to-lob).

## Addressing a version

The same three-way addressing scheme used for [Hugging Face Hub models](/docs/working-with-models/hugging-face-models#addressing-a-model-by-revision) - an exact commit hash, or a named, potentially-moving reference - applies to a Lob-versioned checkpoint. A commit hash is the only form guaranteed stable; anything named can move underneath you, which is exactly what a stale-note is designed to catch.

## What "branch" means here, for now

A branch, in the general sense, is a named line of divergent history - but Lob's specific branch and merge semantics for *weight* history (as opposed to text) aren't finalized. What's confirmed today is narrower: Tensormorph can load and diff a **weight-space pull request** (a Lob-side reviewable proposal) against its base, and can detect when two proposals conflict - see [Reviews](/docs/hub-and-collaboration/reviews) and [Merge Conflicts](/docs/compare-and-morph/merge-conflicts). Treat anything beyond that - a full branch-switching UI inside Tensormorph, for instance - as plausible future direction rather than documented behavior.

## Related resources

-   [Merge Conflicts](/docs/compare-and-morph/merge-conflicts) - the fullest picture of what's confirmed about the Lob boundary today.
-   [Lob CLI](/docs/cli-and-automation/lob-cli) - where actual branch and history operations happen today, outside Tensormorph.
-   [Reviews](/docs/hub-and-collaboration/reviews) - reviewing a weight-space pull request from inside Tensormorph.