---
name: session-prep
description: "Use when a GM is preparing for an upcoming TTRPG session, reconciling what happened last time with what comes next, or reviewing prep plans. This is the between-sessions skill for looking forward — processing the aftermath of the last session into preparation for the next one. Not for during-play help (session-play) or post-session wrap-up (session-wrapup)."
---

Session preparation assistant. Builds on what session-wrapup
established as canon to get the GM ready for next session.
Workflow: Reconcile → Gather → Plan → Verify → Handoff.

**Shared references:** Read `shared/session-principles.md` on
first invocation.

**Version check:** On first invocation, read
`gm_apprentice_version` from `_meta/vault-config.md` and
`current_version` from `shared/migrations.md`. If the vault
version is lower or absent, announce the mismatch and hand off
to campaign-organizer's migration workflow
(`campaign-organizer/references/migration-procedure.md`) before
proceeding with prep. Resume after migration completes. Skip
this check if `_meta/` doesn't exist (that's first-time setup,
not migration).

**Document chain:** Read `shared/session-document-chain.md`.
Session-prep writes Plan files and updates the session index.
It reads previous Wrap-Up files for context — normally never
Play Notes or Plan files from other sessions (exception: raw
Play Notes may be read as a fallback when no Wrap-Up exists,
to generate a recap only — see step 7).

**Trigger phrases:** "prep my session", "plan my session",
"getting ready for next week", "what should I prepare",
"reconcile", "what did we skip", "what changed"

**Session note templates:** Read `references/session-templates.md`
when creating or updating session notes.

**Creative planning references:** Read
`skills/ttrpg-expert/arc-spotlight-reference.md` before
starting creative planning (steps 11-14). For system-specific
arc drivers, also read the active campaign's system
`session-procedures.md`.

**Progressive file writes:** Every step writes its output to
the Plan file before proceeding. The Plan file is the
persistent artifact — conversation is ephemeral.

## Context Source

**Read pattern:**
1. Last session's Wrap-Up file — primary context
2. PC roster — always
3. Vault dives — targeted reads only, proportional to
   upcoming session complexity, not campaign size

## Phase 1: Reconcile (conditional)

Runs when most recent session has status `wrap-up` (not yet
`reviewed`). Skip for first sessions or when already `reviewed`.

**Invoke `shared/reconcile.md`.** Reconcile walks the GM through
reviewing the Wrap-Up, promotes confidence, and handles
salvageable prep triage. See the shared procedure for the full
workflow.

**Reconcile-to-Prep handoff:** Reconcile writes
`## Reconciliation Context` to the Wrap-Up file, capturing
consequences, salvageable prep, and GM decisions. Steps 7-10
read this and only gather what's new.

## Phase 2: Prep Forward — Context Gathering

**6. Existing prep review** — If a Plan file (`type: session-plan`)
already exists for the upcoming session, read it and determine
what's already covered. Flag what needs updating vs what can
stand. Skip gathering for sections already present unless
Reconcile invalidated them.
→ Write `## Prior Prep Review` to Plan file.

**7. Recap** — Present the "Previously on..." narrative recap from last
session's Wrap-Up file (generated by session-wrapup).
→ Write `## Previously On...` to Plan file.

If no recap exists (GM skipped wrap-up):

> "The last session doesn't have a Wrap-Up file yet. I can
> generate a quick 'Previously on...' from raw play notes,
> but the vault won't have been updated — no new entities,
> no existing entity updates, no timeline entries, no
> carry-forward. Want me to do a full wrap-up first
> (recommended), or just the quick recap?"

Skipping wrap-up means entity updates and creation don't
happen. The vault stays frozen at pre-session state.

**8. Threads** — Review carry-forward + unresolved questions,
impressive NPCs, unfollowed clues, pending consequences.
Flag stale threads (3+ sessions without advancement).
Reference `skills/ttrpg-expert/continuity-engine.md` for
stale thread detection.
→ Write `## Active Threads` to Plan file.

**9. Key NPCs** — NPCs likely to appear, with status,
motivations, off-screen activity. Read vault files only for
those flagged in carry-forward or threads.
→ Write `## NPC Quick Reference` to Plan file.

**10. World state** — From Wrap-Up file's World State section.
Date, location, threats, factions, clocks.
→ Write `## World State` to Plan file.

If Reconcile ran, steps 7-10 read `## Reconciliation Context` and skip
what's already established.

## Phase 2: Prep Forward — Creative Planning

**11. PC Roster + Arc Check** — Per-PC deep review:
- Backstory hooks, stated goals, current arc stage (five-stage
  model), arc theme, relationships with other PCs and NPCs
- Decisions from recent sessions needing consequences
- Mechanical highlights (signature abilities, resources)
- Last spotlight level, sessions since last B-plot feature
- Next arc beat: what should happen next in this PC's arc

Then assign A/B/C plot roles for the upcoming session:
- **A-plot** (50-60%): main campaign storyline, all PCs
- **B-plot** (25-35%): one featured PC, personal arc focus
- **C-plot** (10-15%): lighter personal touch for a second PC

→ Write `## PC Roster & Arcs` to Plan file.

**12. Touchpoint Assignment** — Assign at least one touchpoint
per PC using the six types from arc-spotlight-reference.md:
Backstory Connection, Moral Dilemma, Ability Showcase,
Decision Callback, Arc Advancement Clue, Character Moment.

B-plot PC gets at least one high-impact touchpoint. Vary types
across PCs within the session. Coverage check: every PC must
have at least one assigned touchpoint. No PC should go 3+
sessions without a high-impact touchpoint.
→ Write `## Touchpoint Plan` to Plan file.

**13. Scene Design** — Design scenes that deliver the assigned
touchpoints. **Propose each scene to the GM before writing it.**

For each scene, pitch it first:
- 1-2 sentence summary (what happens, why it matters)
- Scene type (investigation, social, combat, chase, horror, other)
- Dramatic objective
- Key entities involved (NPCs, locations, items)
- Which PC touchpoints it delivers

Wait for the GM to **approve**, **tweak**, or **reject**:
- **Approve** — write the scene to the Plan file
- **Tweak** — incorporate the GM's changes, then write
- **Reject** — drop the scene, move to the next proposal

Prefer embedding personal content in group scenes over
splitting the party. Include open interaction windows where
PC initiative can emerge naturally. The GM may also propose
their own scenes at any point — confirm understanding, then
write.

→ Write each approved scene to `## Planned Scenes` in Plan file.

**14. Spotlight Forecast** — Estimate per-PC spotlight share
for the planned session. Check:
- 15% floor: any PC below ~15% needs corrective adjustment
- Sustained imbalance: any PC underserved for 3+ consecutive
  sessions needs immediate corrective action (B-plot feature,
  high-impact touchpoint, or encounter built around their
  strengths)
- Apply corrective B/C plot adjustments if needed

→ Write `## Spotlight Forecast` to Plan file.

## Phase 2: Verify

**15. Agency + Canon Audit** — Review all planned content.

Agency violations (ref: `skills/ttrpg-expert/scenario-writing.md`):
- PC name as subject of declarative action verb
- PC emotions/thoughts/internal state described
- PC actions assumed without conditional language
- Read-aloud using 2nd-person emotion/perception verbs
- Confrontation scene without ≥2 contingencies

Canon violations (ref: `skills/ttrpg-expert/continuity-engine.md`):
- NPC details, locations, or events not traceable to vault
- Unverified claims flagged as such, not stated as canon

→ Write `## Audit Notes` to Plan file.

**16. Gap Check** — Flag:
- PCs without touchpoints (should not happen after step 12)
- NPCs referenced but lacking vault files
- Locations not described
- Stale entity files: flag for update vs retire
- Missing entity stubs needed for planned scenes

→ Write `## Gaps & Actions` to Plan file.

## Handoff

**17. Skill handoff** — Conversational only, not written to
Plan file. Based on gaps and actions identified:
- Content creation (scenes, NPCs, locations) → `ttrpg-expert`
- Vault structure (entity files, metadata, organization) →
  `campaign-organizer`
- Structural issues (broken links, schema violations, graph
  health) → `campaign-qa`

## Sub-agent Opportunity

- Steps 7-10: independent vault reads — parallelizable.
- Steps 11-14: sequential creative planning — run in order.
- Steps 15-16: independent quality checks — parallelizable.

If sub-agents unavailable, run all steps sequentially.