Session Handoff

Bridges sessions. The user's session ends; the next session picks up exactly where the last one left off.

SessionStart catchup

Triggered automatically by the SessionStart hook. Manually invokable via /mddesign:handoff catchup.

Step 1: Read planning files

• Read task_plan.md if it exists. Note the active phase id and its bullets.
• Read findings.md if it exists. Note any ## Design Context block.
• Read progress.md if it exists. Note the most recent ### Phase <id> Result and the most recent ### Handoff <timestamp> entry.

Step 2: Read scratch

• Glob .agents/memory/scratch/**/*.md.
• For each scratch file, read the last ISO-timestamped entry.

Step 3: Recall last WHY

• Invoke /memory-router with a query like "recent decisions for project <CWD basename>".
• The router dispatches to MemPalace; returns the most recent WHY entries for this project.

Step 4: Synthesize the preamble

Build a one-paragraph (4-6 sentence) "where we left off" that names:

• The active phase and its current status
• The most recent decision (from WHY)
• Any open questions from the last ### Phase Result
• Any in-flight scratch entries

Print this preamble to the user as your first message.

Step 5: Surface nudges

• If the project has UI files (*.tsx|*.vue|*.svelte) but no DESIGN.md, print: "No DESIGN.md found. Run /mddesign:harvest to generate one."
• If task_plan.md does not exist, print: "No task_plan.md. Use planning-with-files to create one before starting work."
• If code-memory-router slash command is not registered, print: "code-memory-router not detected. Memory operations will fall back to scratch only."

Stop promotion

Triggered automatically by the Stop hook. Manually invokable via /mddesign:handoff promote.

Step 1: Dispatch memory-keeper

Call the Agent tool with subagent_type: memory-keeper. Pass:

• A pointer to progress.md (last 50 lines)
• A pointer to findings.md
• A pointer to .agents/memory/scratch/

Memory-keeper returns a list of promotion candidates with tier classifications.

Step 2: HITL on each promotion

For each WHY candidate:

• Print the candidate text and the proposed MemPalace drawer path.
• Wait for the PreToolUse hook (named checkpoint: before_mempalace_write) to require approval.
• On approval, the memory-layer skill performs the actual /memory-router invocation.
• On rejection, leave the entry in scratch.

Step 3: Write the handoff note

Append to progress.md:

### Handoff <ISO timestamp>

**Active phase at session end:** <id>
**Status:** <status>
**Promoted to WHY:** <count> entries
**Open questions:**
- <list>

**Resume next session by:**
- <one-line action>

This block is what SessionStart catchup reads first next time.

Manual handoff

Subcommand	What it does
/mddesign:handoff (no arg)	Runs catchup.
/mddesign:handoff catchup	Runs catchup.
/mddesign:handoff promote	Runs Stop promotion. Useful before a planned /clear.

Core rules

• Never touch task_plan.md directly. Read only.
• Never write to MemPalace without HITL.
• Catchup is read-only. Only the promotion step writes (and only under HITL).
• The handoff note in progress.md always lives under ### Handoff <timestamp> for easy grep.

Example

User ends Tuesday session mid-Phase 3. Stop fires. Memory-keeper proposes 2 WHY candidates ("decided X for reason Y" and "rejected approach Z"). User approves both. Plugin writes:

### Handoff 2026-04-23T18:42:11Z

**Active phase at session end:** phase-3-build-cta
**Status:** in_progress, button component scaffolded but a11y not yet checked
**Promoted to WHY:** 2 entries
**Open questions:**
- Should the focus ring use colors.primary or colors.accent?

**Resume next session by:**
- Read findings.md "## Design Context", then run /mddesign:critique to check the button against DESIGN.md tokens.

Wednesday morning, user opens a new session. /clear happened or the laptop rebooted. SessionStart fires. Catchup synthesises:

Last session ended in Phase 3 (build-cta), button scaffolded but a11y not yet checked. Decisions promoted: chose primary color for CTA based on contrast vs accent. Open question: focus ring color (primary vs accent). Suggested next step: read findings.md "## Design Context" then /mddesign:critique.

User reads, says "ok continue". The agent already has every piece of context it needs.