diff --git a/.pi/skills/dev-serve/SKILL.md b/.pi/skills/dev-serve/SKILL.md
new file mode 100644
index 0000000..d44a65a
--- /dev/null
+++ b/.pi/skills/dev-serve/SKILL.md
@@ -0,0 +1,126 @@
+---
+name: dev-serve
+description: |
+  Boots the TTRPG Initiative Tracker dev stack (Node backend + CRA frontend) for
+  hands-on human testing, then opens a headed browser window the user can see and
+  click. Use when user says "let me test", "open it for me", "give me a browser",
+  "run it locally", "boot the app", or wants to manually use the app. Handles
+  STORAGE mode selection (ws vs firebase), port collision cleanup, background
+  process management, and headed agent_browser launch in one shot.
+---
+
+# dev-serve
+
+Run the full app stack for human testing, then open a headed browser window the
+user can see and drive.
+
+## Prerequisites
+
+- Repo root has `server/`, `shared/`, `src/` (npm workspaces).
+- Node 18+.
+- Ports 4001 (backend) and 3999 (frontend) free, or let this skill kill stale procs.
+
+## Defaults
+
+- Backend: `DB_PATH=/tmp/tracker-dev.sqlite PORT=4001`
+- Frontend: `REACT_APP_STORAGE=ws` (self-hosted backend) unless user asks for firebase.
+  Override: user says "firebase mode" → `REACT_APP_STORAGE=firebase` + requires
+  `.env.local` with `REACT_APP_FIREBASE_*`.
+- Frontend port: `3999`. Backend: `4001`.
+
+## Steps
+
+### 1. Kill stale procs (idempotent)
+
+```bash
+pkill -f "node server/index.js" 2>/dev/null
+pkill -f "react-scripts start" 2>/dev/null
+sleep 2
+```
+
+Do not error if pkill finds nothing.
+
+### 2. Boot backend (background, log to /tmp)
+
+```bash
+rm -f /tmp/tracker-dev.sqlite*
+DB_PATH=/tmp/tracker-dev.sqlite PORT=4001 nohup node server/index.js > /tmp/tracker-backend.log 2>&1 &
+sleep 2
+curl -s http://127.0.0.1:4001/health   # must return {"ok":true}
+```
+
+If health fails, tail `/tmp/tracker-backend.log`, diagnose, fix. Do not proceed.
+
+### 3. Boot frontend (background, log to /tmp)
+
+```bash
+REACT_APP_STORAGE=ws \
+REACT_APP_BACKEND_URL=http://127.0.0.1:4001 \
+REACT_APP_BACKEND_WS=ws://127.0.0.1:4001/ws \
+BROWSER=none PORT=3999 nohup npm start > /tmp/tracker-frontend.log 2>&1 &
+```
+
+Wait ~10s, then confirm compile:
+
+```bash
+grep -E "Compiled successfully|Failed to compile" /tmp/tracker-frontend.log | tail -1
+```
+
+`BROWSER=none` stops CRA from stealing focus; we open our own headed window.
+
+### 4. Open headed browser window for user
+
+Use `agent_browser` tool, fresh session (headed flag is launch-scoped):
+
+```json
+{
+  "agent_browser": {
+    "args": ["open", "http://127.0.0.1:3999", "--headed"],
+    "sessionMode": "fresh",
+    "timeoutMs": 20000
+  }
+}
+```
+
+Then snapshot to confirm UI rendered (look for "TTRPG Initiative Tracker" heading +
+"Create Campaign" button, NOT "Loading campaigns..." after 2-3s).
+
+### 5. Tell user the URL
+
+```
+App:     http://127.0.0.1:3999   (browser window open)
+Backend: http://127.0.0.1:4001
+Logs:    /tmp/tracker-frontend.log, /tmp/tracker-backend.log
+```
+
+User can also navigate to that URL in their own browser if they closed the
+agent_browser window.
+
+## Troubleshooting
+
+| Symptom | Cause | Fix |
+|---------|-------|-----|
+| "Loading campaigns..." stuck | WS subscribe silent fail | Check `/tmp/tracker-backend.log` for WS connection; check ws.js `ensureWs` uses `.onopen/.onmessage` not `.on('open')` |
+| "Configuration Error" screen | firebase mode without `.env.local`, OR init not gated on STORAGE_MODE | Confirm `STORAGE=ws`; confirm `initializeStorage()` gates firebase |
+| Port 4001/3999 EADDRINUSE | stale proc | Rerun step 1 |
+| Campaign created but not visible | WS broadcast not wired, or path prefix not normalized | Check ws.js `norm()` strips `artifacts/.../public/data/` |
+| Headed window not on screen | remote/VM/headless env | `--headed` only guarantees browser context, not OS visibility; tell user env limitation |
+
+## Teardown
+
+When user done testing, kill both:
+
+```bash
+pkill -f "node server/index.js"
+pkill -f "react-scripts start"
+```
+
+Or leave running if user continuing dev. Ask which.
+
+## Storage mode notes
+
+- `ws` (default here): self-hosted backend. Cross-device via backend WS. No Firebase creds needed.
+- `firebase`: original upstream. Needs `.env.local`. Behavior identical per characterization tests.
+- `memory`: in-process, tests only. Resets on reload.
+
+Switching modes mid-session: kill procs, re-export `REACT_APP_STORAGE`, reboot.