diff --git a/domain-skills/proxywar/build-and-deploy.md b/domain-skills/proxywar/build-and-deploy.md
new file mode 100644
index 00000000..1292555b
--- /dev/null
+++ b/domain-skills/proxywar/build-and-deploy.md
@@ -0,0 +1,96 @@
+# proxywar.xyz / beta.proxywar.xyz
+
+League/replay origin. Two separate Vite entries, never mixed:
+`public.html`→`PublicApp.ts` (`assets/public-<hash>.js`) and
+`index.html`→`Main.ts` (`assets/main-<hash>.js`).
+
+## Routes
+
+| Route | Shell |
+|---|---|
+| `/` | `public.html` event lobby |
+| `/league` | static mirror `league/index.html` |
+| `/watch` | `public.html` — links to real `/ai-league-replay/<runKey>` and `/match/<id>` |
+| `/agents` | `public.html` |
+| `/build` | `public.html` — self-serve Builder registration wizard |
+| `/ai-league-replay/<runKey>` | `index.html` game shell — replay/clip/panel UI lives here |
+
+## `/build` wizard
+
+Custom element `<build-page>`. Step tabs: `build-page button[aria-current]`,
+a 7-item NodeList, index 2 = Step 3 "Identity" (the registration form).
+
+Step 3 fields: Agent Name*, Short Code* (2-4 uppercase alphanumeric characters, `/^[A-Z0-9]{2,4}$/`), Tagline, Public
+Strategy Description, Your Builder Name*, GitHub username (optional,
+`[a-zA-Z0-9-]{1,39}`), Short bio, Links (`<textarea>`, one per line),
+Source repository (`<input>`). `*` = required.
+
+Submit: `POST /api/build/registration-submission`, strict-schema JSON body.
+Success: `{ok:true, proposedAgent, proposedBuilder, profileFileJson,
+githubIssueUrl}`. Failure: `{ok:false, error:"invalid_submission", field,
+reason}` — `field` names the exact bad input; `reason` ∈
+`format|required|too_short|too_long|invalid`.
+
+No persistence: this endpoint never writes the identity registry. Success
+only yields a client-rendered draft plus a prefilled GitHub issue URL —
+opening/filing that issue is a separate manual click the wizard never
+triggers.
+
+Field-error DOM ids (targets of the input's `aria-describedby`,
+`aria-invalid` toggles alongside): `build-step3-github-error`,
+`build-step3-links-error`, `build-step3-repo-error`. Any `body.field` not
+matching `claimedGithub`/`builderLinks`/`sourceRepositoryRef` falls back to
+a generic banner, not tied to any input.
+
+## Replay panel collapse
+
+Shared toggle component, per-overlay state/keys:
+
+- Full Replay (`/ai-league-replay/<runKey>`): localStorage keys
+  `ai-league-broadcast-rail-collapsed-v1` (Competitors rail),
+  `ai-league-broadcast-war-room-collapsed-v1` (War Room feed).
+- Premiere overlay: `replay-premiere-broadcast-rail-collapsed-v1`,
+  `replay-premiere-broadcast-war-room-collapsed-v1`.
+
+aria-labels: "Collapse/Expand competitors panel",
+"Collapse/Expand War Room panel"; `aria-expanded` mirrors collapsed state on
+every render including first paint.
+
+## Social clip control
+
+Render button selector: `[data-ai-league-clip-render]` — same component on
+Full Replay and an archived Premiere rewatch. Requires
+`GET /api/clip-capabilities` to report generation enabled, else the whole
+clip section is `hidden`.
+
+Flow: `POST /api/league-runs/<runKey>/clips` (body `{turn}`) starts a
+render, returns a `schemaVersion:1` `pending`/`ready` status envelope. While
+pending, client polls `GET /api/league-runs/<runKey>/clips/<bucket>?progress=1`
+every 3000ms until terminal.
+
+Terminal poll outcomes: 404 → `"failed"`; any other non-2xx → `429`/`503`
+maps to `"busy"`, anything else maps to `"failed"`; both stop polling and
+re-enable the render control. Initial selected bucket is not fixed — it can
+track the replay's live playhead rather than a constant, so any mocked
+response must echo back the bucket the page actually requested.
+
+## Local dev server
+
+`npm run dev` (plain Vite + `src/server/Server.ts`) does not serve `/build`
+or any `/api/build/*`/`/api/league-runs/*` route — wrong server entirely.
+
+Use `src/scripts/ai-agent-demo-server.ts` (`npm run agent:demo-server`)
+instead. It serves a prebuilt `static/` directory, not live Vite HMR — run
+`npm run build-dev` (or `build-prod` for the Full Replay/map asset
+manifest) before starting/restarting it. Boot with
+`PROXYWAR_LEAGUE_WRAPPER_ONLY=true` to match the league-origin posture (also
+skips spawning its own child replay-renderer subprocess). Default port
+`AI_LEAGUE_DEMO_PORT` = 8787.
+
+## Verifying a deploy landed
+
+No `/commit.txt` or version-SHA endpoint exists. Compare content-hashed
+asset filenames instead: `assets/main-<hash>.js` (served at `/`) and
+`assets/public-<hash>.js` (served at `/build`) against the freshly built
+local `static/assets/` output — an exact filename match on both confirms
+the intended commit is live.