diff --git a/.claude/skills/workshop-start/SKILL.md b/.claude/skills/workshop-start/SKILL.md
index df996b8ad..d8928cd37 100644
--- a/.claude/skills/workshop-start/SKILL.md
+++ b/.claude/skills/workshop-start/SKILL.md
@@ -88,9 +88,10 @@ When all Round N tasks are complete:
 
 Wrap-up sequence:
 1. Qatux produces final `workshop-outcomes.md` from accumulated notes
-2. If SI is present, SI creates tickets from decided items
-3. Send shutdown_request to all agents (qatux and si last, after they finish their output tasks)
-4. TeamDelete to clean up
+2. Qatux creates or updates diagrams (via `/d2-diagram`) for any new D-records produced by the workshop
+3. If SI is present, SI creates tickets from decided items
+4. Send shutdown_request to all agents (qatux and si last, after they finish their output tasks)
+5. TeamDelete to clean up
 
 ## Agent Type Reference
 
diff --git a/CLAUDE.md b/CLAUDE.md
index 21e789065..9f5bba849 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -20,6 +20,7 @@ docs/
   briefings/          # Per-agent context briefings (maintained by Qatux)
   architecture/       # Technical architecture documents
   design/             # Game design documents
+  diagrams/           # d2 source + PNG renders (architecture, data-flow, entity, state, ui)
   sprints/            # Sprint briefings per team (server.md, client.md, copy.md, joint.md, etc.)
   workshops/          # Workshop briefs and outputs (per-workshop subdirectories)
 db/
@@ -144,6 +145,7 @@ Key rules:
 ### File conventions
 - Decisions: domain files in `decisions/` (see `decisions/README.md` for index)
 - Decision IDs: `D-NNN` (confirmed), `Q-NNN` (open questions), `R-NNN` (rejected)
+- Diagrams: `.d2` source + `.png` renders in `docs/diagrams/{category}/`. Create or update diagrams via `/d2-diagram` when D-records are added or modified.
 - Discussion rounds: numbered sequentially, archived to `docs/discussions/` when complete
 - Briefings: one per agent, updated after decision-producing rounds
 - Tickets: managed via `db/connectors/ticket` CLI or `/ticket` skill
diff --git a/docs/briefings/qatux.md b/docs/briefings/qatux.md
index d325a161e..03f4096d9 100644
--- a/docs/briefings/qatux.md
+++ b/docs/briefings/qatux.md
@@ -35,13 +35,15 @@ None assigned directly.
 2. Create round documents directly at `docs/discussions/round-NN-topic.md` (D-022 workflow)
 3. Update `docs/discussions/README.md` with new round entries after formal closure
 4. Update relevant agent briefing files with new decision references
-5. Re-index changed documents in Qdrant after updates
-6. Verify briefing freshness against decision domain files
+5. **Create and update diagrams** whenever D-records are added or modified — use the `/d2-diagram` skill to generate d2 source + PNG. New decisions get a diagram if they describe systems, flows, or relationships. Existing diagrams in `docs/diagrams/{category}/` must be updated when their source decisions change. Categories: architecture, data-flow, entity, state, ui.
+6. Re-index changed documents in Qdrant after updates
+7. Verify briefing freshness against decision domain files
 
 ## Key Documents
 - `decisions/` — domain-split decision files (see `decisions/README.md` for index)
 - `docs/discussions/` — archived rounds (including active rounds per D-022)
 - `docs/briefings/` — agent briefing files (you maintain these)
+- `docs/diagrams/` — decision diagrams (architecture, data-flow, entity, state, ui) — `.d2` source + `.png` renders
 - `docs/workshops/` — workshop briefs, outputs, and summaries
 - `TEAM.md` — team roster