plastic-versions - SKILL.md Agent Skill

name: plastic-versions description: Use when the user wants to see their Plastic version history or roll back to a previously-installed version after a bad release. Manages the local, append-only versions.json ledger and steps between versions the user has actually run. For moving to a brand-new release, use plastic-update instead.

Plastic Versions — local version time-machine

When to Use

"show plastic versions", "version history", "what versions have I run"
"roll back plastic", "downgrade", "go back to the version that worked", "revert plastic"
A new version broke something and the user wants their last known-good build

For upgrading to a new release, use plastic-update. This skill only navigates versions you have already installed — the ones recorded in the ledger.

The ledger

~/.plastic/versions.json is an append-only JSONL ledger — one line per version change, never modified or deleted:

{"version":"1.0.0-alpha.17","action":"install","at":"..."}
{"version":"1.0.0-alpha.18","action":"update","at":"..."}

action ∈ install | reinstall | update | downgrade (derived from version direction; the channel is derived from the version string, never stored). It is a troubleshooting record.

Procedure

Show history

npx @zalom/plastic versions

Prints the table with the currently-installed version marked. If the most recent action was a downgrade, it asks whether to keep rolling back.

Roll back

npx @zalom/plastic versions --downgrade                    # one step back
npx @zalom/plastic versions --downgrade --version 1.0.0-alpha.15   # to a specific run

Rollback targets are restricted to versions in the ledger (only builds you have actually run, so you only ever return to something known-good for you). The chosen version is re-fetched from npm and re-synced; your intent store, config, and the ledger are untouched.

Step forward (after a rollback)

npx @zalom/plastic versions --upgrade                      # one step forward in your history

After any change

Run plastic-doctor to confirm health, and suggest /clear so the session picks up the swapped conventions.

Notes

The ledger is never edited or pruned — it is the audit trail.
Downgrades cannot un-migrate a store-format change; if a warning appears, surface it to the user rather than forcing the rollback.