/plan-archive — Dated Plans Archive

Save any plan, architecture decision, or strategic thinking session to a central dated archive with a timestamp. Enables retrospective review of how thinking evolved over time — you can look at "what I planned in April" vs "what I planned in October" and see whether the bets paid off.

Location

Default location: ~/.claude-plans/ (override with the CLAUDE_PLANS_DIR env var).

Rationale vs per-project .claude/plans/:

• Central search — one place to grep / qmd / index. Per-project plans scatter and become invisible to retrospective workflows.
• Lifetime — plans survive project archival, repo deletion, or restructuring. The archive is permanent even when individual repos come and go.
• Retrospectives — comparing plans across months requires them all in one place.
• Consistency — adjacent log folders (daily notes, decisions, weekly retros) usually live in the same root; plans fit the same pattern.

Per-project .claude/plans/ is the right choice ONLY when the plan is so code-specific that it's meaningless without the repo context. That's rare — even those are usually worth preserving centrally.

Inputs

• No argument — synthesize and archive the current planning session from conversation context
• topic:<slug> — override the auto-generated topic name (e.g., topic:auth-flow-refactor)
• file:<path> — archive an existing plan document rather than synthesizing from context

Process

Step 1 — Determine Topic and Date

Generate a topic slug from the current conversation:

• Identify the main decision or architecture question being planned
• Convert to lowercase-hyphen slug: e.g., "Auth flow refactor" → auth-flow-refactor
• If topic:<slug> was provided, use that instead
• Date: today's ISO date (YYYY-MM-DD)
• Resolve archive root: ${CLAUDE_PLANS_DIR:-$HOME/.claude-plans}
• Final filename: <archive-root>/YYYY-MM-DD-{slug}.md

Confirm with: "Archiving plan to <archive-root>/YYYY-MM-DD-{slug}.md — proceed?"

Step 2 — Synthesize Plan Content

If synthesizing from conversation context:

• Extract the key decision that was made
• Extract the approach that was chosen
• Extract alternatives that were considered and rejected (with reasons)
• Extract open questions that remain
• Extract any constraints or assumptions that shaped the decision

If archiving from file: read the file as-is, append standard frontmatter.

Step 3 — Write Archive File

Format:

# Plan: {Human-readable topic} — {YYYY-MM-DD}

**Status**: drafted
**Session context**: {1-line description of what problem this was solving}

## Context

{What problem triggered this plan. Key constraints. What was already tried or considered.}

## Decision / Approach

{The actual plan — what was decided and why. Be specific enough that someone reading this later (or a future AI session) can understand without the original conversation.}

## Alternatives Considered

| Alternative | Why Rejected |
|-------------|-------------|
| {option A} | {reason} |
| {option B} | {reason} |

## Open Questions at Time of Archival

- [ ] {question 1}
- [ ] {question 2}

## Retrospective

> *(Fill in when revisiting — was this the right call? What changed? What would you do differently?)*
> *(Status: drafted | revised | implemented | abandoned | superseded-by: YYYY-MM-DD-{other-plan})*

Step 4 — Commit (if archive root is a git repo)

If <archive-root> is inside a git repo, commit the new file:

cd <archive-root> && git add . && git commit -m "Archive plan: {slug}"

If not a git repo, just confirm the file was written: "Plan archived to <archive-root>/YYYY-MM-DD-{slug}.md."

Auto-Capture via end-of-session ritual

Pair this skill with a session-close skill (or your own end-of-session ritual) that scans the ending session for substantive planning work and prompts once to archive. The reason to capture at session-close rather than at every ExitPlanMode:

• Plan mode often gets entered/exited multiple times per session for trivial "which approach" micro-decisions — hooking ExitPlanMode would flood the session with archive prompts.
• By session-close time the plan has been implemented (or explicitly deferred). The session has the full context — decision + execution + retrospective seed — which makes for a richer archive than a premature capture at exit-plan-mode time.

Heuristic for triggering the prompt:

• Session explicitly entered plan mode
• Alternatives were weighed before committing
• The design settled over >3 exchanges
• A decision was made that will affect future sessions

Skip purely tactical sessions: bug fixes, routine triage, comms, single-file edits with no alternatives considered.

To force-archive a session that the heuristic skipped: run /plan-archive directly.

Retrospective Workflow

When revisiting an archived plan:

1. Find the file in the archive (grep, ripgrep, or your favorite indexer)
2. Update Status frontmatter field: drafted → implemented or drafted → abandoned
3. Fill in the Retrospective section: what happened, was it right, what changed
4. If plan was superseded: add superseded-by: YYYY-MM-DD-{new-slug} to the status line

The retrospective isn't for posterity — it's for training future-you (and future-AI). When a new plan resembles an old one, the retrospective tells you whether similar bets paid off.

Example Invocations

/plan-archive                              # synthesize from current conversation
/plan-archive topic:database-migration-v3  # specific topic slug
/plan-archive file:./notes/2026-04-25.md   # archive existing doc