plan

name	plan
description	Reads the capability specs changed on this branch and writes a technical plan. Optional — skip for straightforward changes and go straight to /code.
model	opus
disable-model-invocation	true

/plan

Translates spec changes on the current branch into a technical plan. Use for non-trivial features where the approach warrants discussion before coding starts.

Input

$ARGUMENTS — an optional issue ID or slug used to name the plan directory (e.g. MXB-7). If empty, derives from the branch name.

Steps

1. Discover changed specs

git diff main --name-only -- specs/

Read each changed spec file in full. Then read the diff to understand what is new:

git diff main -- specs/<feature>/spec.md

If no specs have changed on this branch, tell the user and stop.

2. Determine plan directory name

If $ARGUMENTS is provided: changes/<arguments>-<feature>/plan.md Otherwise derive from branch name: changes/<branch-slug>/plan.md

3. Write plan.md

# Plan: <Title>

**Spec:** `specs/<feature>/spec.md`
**Branch:** `<branch>`

## Approach

<Technical description. What components, server functions, data flow, state management.
1-3 paragraphs.>

## File Changes

| File | Action | Notes |
|------|--------|-------|
| `src/features/<feature>/...` | create | ... |

## Decisions

<Key technical choices and why this approach over alternatives. Omit if nothing significant.>

4. Write ADR if warranted

Warranted when the plan involves a new dependency, a change to established architecture, a new pattern being introduced for the first time, or a decision future developers would otherwise re-litigate.

ls docs/adr/*.md 2>/dev/null | wc -l

Create docs/adr/NNNN-<slug>.md using MADR v3 format. Skip if none of the above apply.

5. Simplify

Run /simplify to review the plan and ADR for clarity, redundancy, and quality.

6. Commit

git add changes/ docs/adr/
git commit -m "docs: plan <slug>"

7. Output summary

Print:

• Plan path
• ADR path if written
• Key decisions made

Constraints

• Do NOT write implementation code
• Do NOT update a plan after /code has started — create a new entry if the approach changes