diff --git a/.cursor/Dockerfile b/.cursor/Dockerfile
new file mode 100644
index 0000000..0b22fdf
--- /dev/null
+++ b/.cursor/Dockerfile
@@ -0,0 +1,12 @@
+FROM node:26-bookworm-slim
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends git curl \
+    && rm -rf /var/lib/apt/lists/* \
+    && npm install -g pnpm@11.1.3
+
+RUN mkdir -p /workspace \
+    && chown -R node:node /workspace /home/node
+
+USER node
+WORKDIR /workspace
diff --git a/.cursor/environment.json b/.cursor/environment.json
new file mode 100644
index 0000000..f20a675
--- /dev/null
+++ b/.cursor/environment.json
@@ -0,0 +1,8 @@
+{
+  "name": "Open Watch Party",
+  "user": "node",
+  "build": {
+    "dockerfile": "Dockerfile"
+  },
+  "install": "pnpm install --frozen-lockfile"
+}
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..d9785dd
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,12 @@
+# AGENTS.md
+
+## Cursor Cloud specific instructions
+
+Open Watch Party is a pnpm workspace (pnpm 11, Node 26 via `.cursor/Dockerfile`).
+Standard commands are in the root `package.json` and `README.md`.
+
+Services:
+- `apps/server`: `pnpm dev:server` → `wrangler dev` on `http://localhost:8787`. No Cloudflare account needed for local dev.
+- `apps/extension`: `pnpm dev:extension` → WXT dev server on `http://localhost:3000`. The auto-launched browser has no display in headless VMs.
+
+Non-obvious: `wrangler dev` uses port `8787`, not the `localhost:1999` default in `apps/extension/.env.example` (that's for a deployed host). `apps/server/.wrangler/` is untracked local state, safe to delete.