Undo Implementation

Discard uncommitted code changes, reversibly, before they are committed. Works in two contexts:

• In a pipeline — discards what /sdd:implement accumulated before /sdd:commit, while keeping .specwork/ (spec, plan, cache, state) intact so you can fix the spec and re-implement.
• Standalone (vibe coding) — no .specwork/ required; it just cleans your working tree so you can keep coding. Pairs with /sdd:commit as the "undo" half of the vibe loop.

/sdd:undo            # reversible: stash the changes (recover with --restore)
/sdd:undo --restore  # bring back the last undone changes (redo)
/sdd:undo --hard     # irreversible: revert tracked edits + delete new files

When a pipeline is active, .specwork/ is always preserved — it is gitignored, so it never enters a stash and is never removed by git clean (this skill never passes -x).

This is not /sdd:pause. /sdd:pause stashes everything including .specwork/ to switch branches. /sdd:undo stashes only the source changes and leaves the pipeline active so you can re-spec immediately. It also only applies to uncommitted work — if you already ran /sdd:commit, see Already committed? below.

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Execution

Step	Action
0	Resolve mode from $ARGUMENTS: none → reversible undo · --restore → recover · --hard → irreversible
1	Preview what will be affected (skip for --restore)
2	Confirm with the user (skip for --restore; required for undo and --hard)
3	Run the matching revert.py subcommand
4	Point the user back to /sdd:spec → /sdd:plan → /sdd:implement

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Step 1 — Preview (undo / --hard)

Show exactly what will be discarded before doing anything. .specwork/ is gitignored so it never appears here:

python3 ${CLAUDE_PLUGIN_ROOT}/lib/revert.py preview

• Exit code 1 ((clean — nothing to undo)): stop — there is nothing to undo.
• Otherwise: the printed paths are the tracked edits and new files that will be reverted. Present them to the user.

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Step 2 — Confirm (undo / --hard)

Always confirm before discarding work. Use a single AskUserQuestion:

• Reversible undo — "Stash these N change(s)? Recoverable with /sdd:undo --restore."
• --hard — make the irreversibility explicit: "Permanently revert these N change(s)? This cannot be undone."

In non-interactive mode (gates.py non-interactive <slug> is true), do not prompt: proceed only for the reversible undo; refuse --hard and tell the user to run it interactively.

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Step 3 — Run

Reversible undo (default). Pass the feature slug so the stash is labeled and /sdd:undo --restore can find it:

SLUG="$(python3 ${CLAUDE_PLUGIN_ROOT}/lib/gates.py resolve-slug 2>/dev/null || true)"
python3 ${CLAUDE_PLUGIN_ROOT}/lib/revert.py undo --slug "$SLUG"

Recover the last undo (redo):

python3 ${CLAUDE_PLUGIN_ROOT}/lib/revert.py restore

Irreversible discard:

python3 ${CLAUDE_PLUGIN_ROOT}/lib/revert.py hard

List recoverable undo stashes:

python3 ${CLAUDE_PLUGIN_ROOT}/lib/revert.py list

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Step 4 — Next

Branch the guidance on whether a pipeline is active:

python3 ${CLAUDE_PLUGIN_ROOT}/lib/gates.py precheck   # exit 0 = pipeline active

• Pipeline active — the implementation is gone but .specwork/ is intact. Guide the user to correct the spec and re-implement:

  Implementation discarded; .specwork/ preserved.
  
    /sdd:spec <correction>   # refine the spec (resolve/append Open Questions)
    /sdd:plan                # re-run: the spec is now newer than the plan (stale gate)
    /sdd:implement
  

• Standalone (vibe coding) — the working tree is clean again. Just keep coding, then /sdd:commit when ready.

In both cases, if they undid by mistake: /sdd:undo --restore.

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Already committed?

/sdd:undo only handles uncommitted work. If the bad implementation is already in a commit (e.g. after /sdd:commit), this skill does not rewrite history. Tell the user that is a git reset operation and let them decide:

• git reset --soft HEAD~1 — undo the commit, keep changes staged
• git reset --hard HEAD~1 — undo the commit and discard changes (irreversible)

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Related Skills

• pause / restore — stash/restore the whole pipeline (including .specwork/) to switch branches
• spec — re-draft / refine the spec after undoing
• close — the opposite of /sdd:undo: wipes .specwork/ and leaves the code