> ## Documentation Index
> Fetch the complete documentation index at: https://developer.ubiquex.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Drift

> Reality diverging from the ledger becomes an implicit proposal, not a silent overwrite.

Drift is what `ubx` calls it when reality — what's actually running in
the cloud — no longer matches what the ledger says should be true.
Someone clicked around in a console, a Lambda auto-updated itself, an
out-of-band script changed a tag. `ubx scan` detects this the same way
it detects anything new: by observing live state and comparing it
against the ledger's own folded truth, not against whatever was last
observed.

## Drift becomes a proposal, never a silent write

The moment `ubx scan` finds drift, it doesn't resolve it by itself. It
generates a [proposal](/concepts/proposal) — an implicit one, since
nobody authored intent for it, but a real, resolvable, acceptable one
all the same, exactly like any hand-authored change. There are two
possible resolutions, and `ubx` never auto-picks one by default:

* **`drift_adopt`** — records that reality's new state is now the
  ledger's own truth. All-zero blast radius by construction: nothing
  about the cloud changes, only the record does.
* **`drift_revert`** — the opposite decision: the ledger's existing value
  was correct, and reality needs to be corrected back to it. This one has
  a real, non-zero blast radius — accepting it is a decision to change
  live infrastructure, computed as `diffAttributes(observed, ledgerState)`,
  the exact reverse of what `drift_adopt` would have recorded.

`ubx scan --propose adopt|revert|both` controls which gets generated;
`both` produces two independent draft proposals sharing the same parent,
alternative resolutions to the same detected drift — whichever gets
accepted first advances the chain, and the other becomes stale the
instant that happens, the same ordinary parent-mismatch staleness every
other proposal is subject to.

## Compared against ledger truth, not the last observation

A precise, load-bearing detail: drift detection folds the ledger fresh
and compares against *that*, not against whatever `ubx` happened to
observe the last time someone ran a scan. A drift that gets adopted
becomes the new ledger truth immediately — the next scan compares
against the adopted value, not the pre-drift one.

Full detail, including the revert path's own `ubx revert-plan` (emits, never
applies) and the staleness interaction: [`docs/architecture.md`](https://github.com/Ubiquex/ubiquex/blob/main/docs/architecture.md)'s
"Revert path" section in `ubiquex`.