turnstile-spin: pivot SKILL to canonical siteverify

Drop the Worker deploy step from the wizard. Spin's job is now
widget creation plus a curated agent prompt that wires canonical
server-side siteverify into the customer's existing backend.

Changes:
- SKILL.md rewritten end-to-end (167 -> 211 lines)
- worker-deploy.sh deleted
- templates/worker/ deleted (14 files)
- auth-probe.sh drops Workers Scripts scope check
- validate.sh rewritten to dummy-token siteverify + optional hostname check
- All 6 framework references rewritten for canonical siteverify
- README.md + tests/validation.md updated

Pairs with cloudflare/cloudflare-docs and cloudflare/fe/stratus !39261.

Author: Jules Lemee

skills/turnstile-spin/README.md

@@ -9,13 +9,18 @@ This is a mirror of the canonical docs page at [`developers.cloudflare.com/turns
 | File                              | Purpose                                                                |
 | --------------------------------- | ---------------------------------------------------------------------- |
 | `SKILL.md`                        | Main wizard instructions for the agent                                 |
+| `scripts/auth-probe.sh`           | Probes the customer's Cloudflare API token for Turnstile scope         |
+| `scripts/widget-create.sh`        | Creates the Turnstile widget via the Cloudflare API                    |
+| `scripts/fetch-secret.sh`         | Retrieves the secret for an existing widget (recovery flow)            |
+| `scripts/validate.sh`             | Dummy-siteverify + hostname check at the end of the wizard             |
+| `scripts/persist-skill.sh`        | Installs the canonical skill bundle into the user's repo               |
 | `references/vanilla-html.md`      | Code snippet for static / vanilla HTML projects                        |
 | `references/nextjs-app.md`        | Code snippet for Next.js App Router projects                           |
 | `references/nextjs-pages.md`      | Code snippet for Next.js Pages Router projects                         |
 | `references/astro.md`             | Code snippet for Astro projects                                        |
 | `references/sveltekit.md`         | Code snippet for SvelteKit projects                                    |
 | `references/hugo.md`              | Code snippet for Hugo projects                                         |
-| `tests/validation.md`             | Validation cases matching the MVP rows in the PRD                      |
+| `tests/validation.md`             | Validation cases matching the assertions in the PRD                    |
 
 ## How agents load it
 
@@ -32,14 +37,14 @@ git clone https://github.com/cloudflare/skills ~/.config/cloudflare-skills
 ln -s ~/.config/cloudflare-skills/turnstile-spin ~/.claude/skills/turnstile-spin
 ```
 
-For other agents, see the table in [`SKILL.md`](./SKILL.md#step-8--persist-the-skill).
+For other agents, see the table in [`SKILL.md`](./SKILL.md#step-11--persist-the-skill).
 
 ## Sync with the docs page
 
-The canonical source of truth is `src/content/docs/turnstile/spin/index.mdx` in the `cloudflare-docs` repo. This skill mirrors that content with the JSX stripped out. CI keeps them in sync on each docs release; if you are hand-editing, mirror your change to both places.
+The canonical source of truth is `src/content/docs/turnstile/spin.mdx` in the `cloudflare-docs` repo. This skill mirrors that content with the JSX stripped out. CI keeps them in sync on each docs release; if you are hand-editing, mirror your change to both places.
 
 ## Related
 
 - [Canonical docs page](https://developers.cloudflare.com/turnstile/spin/)
-- [`cloudflare/turnstile-siteverify`](https://github.com/cloudflare/turnstile-siteverify) — the managed Worker that this skill deploys
 - [`cloudflare/skills`](https://github.com/cloudflare/skills) — root index for all Cloudflare agent skills
+- [Turnstile server-side validation](https://developers.cloudflare.com/turnstile/get-started/server-side-validation/) — canonical siteverify reference

skills/turnstile-spin/SKILL.md

@@ -1,10 +1,9 @@
 # Astro
 
-For Astro projects. The form posts directly to the Worker. Astro frontmatter handles config substitution at build time.
+For Astro projects. The widget renders in a page; siteverify lives in an Astro Action, an API route, or a Pages Function. Astro frontmatter reads the sitekey from env at build time; the secret stays server-only.
 
 ```astro title="src/pages/signup.astro"
 ---
-const WORKER_URL = import.meta.env.PUBLIC_TURNSTILE_WORKER_URL;
 const SITEKEY = import.meta.env.PUBLIC_TURNSTILE_SITEKEY;
 ---
 
@@ -17,12 +16,12 @@ const SITEKEY = import.meta.env.PUBLIC_TURNSTILE_SITEKEY;
 		></script>
 	</head>
 	<body>
-		<form action={`${WORKER_URL}/`} method="POST">
+		<form action="/api/signup" method="POST">
 			<input name="email" type="email" required />
 			<div
 				class="cf-turnstile"
 				data-sitekey={SITEKEY}
-				data-action="turnstile-spin-v1"
+				data-action="turnstile-spin-v2"
 			/>
 			<button type="submit">Sign up</button>
 		</form>
@@ -33,36 +32,36 @@ const SITEKEY = import.meta.env.PUBLIC_TURNSTILE_SITEKEY;
 In your `.env`:
 
 ```text
-PUBLIC_TURNSTILE_WORKER_URL=https://YOUR_WORKER_URL
 PUBLIC_TURNSTILE_SITEKEY=YOUR_SITEKEY
+TURNSTILE_SECRET=YOUR_SECRET
 ```
 
-The `PUBLIC_` prefix is mandatory for client-exposed variables in Astro.
+The `PUBLIC_` prefix is mandatory for client-exposed variables in Astro. The secret has **no** prefix; it stays server-only.
 
-## Variant: hardcoded values
+## API route (canonical siteverify)
 
-If you do not use env vars, inline directly:
+```ts title="src/pages/api/signup.ts"
+import type { APIRoute } from "astro";
 
-```astro title="src/pages/signup.astro"
-<html>
-	<head>
-		<script
-			src="https://challenges.cloudflare.com/turnstile/v0/api.js"
-			async
-			defer
-		></script>
-	</head>
-	<body>
-		<form action="https://YOUR_WORKER_URL/" method="POST">
-			<div
-				class="cf-turnstile"
-				data-sitekey="YOUR_SITEKEY"
-				data-action="turnstile-spin-v1"
-			/>
-			<button type="submit">Sign up</button>
-		</form>
-	</body>
-</html>
+export const POST: APIRoute = async ({ request, clientAddress }) => {
+	const form = await request.formData();
+	const token = form.get("cf-turnstile-response") as string;
+
+	const verify = await fetch("https://challenges.cloudflare.com/turnstile/v0/siteverify", {
+		method: "POST",
+		headers: { "Content-Type": "application/x-www-form-urlencoded" },
+		body: new URLSearchParams({
+			secret: import.meta.env.TURNSTILE_SECRET,
+			response: token,
+			remoteip: clientAddress,
+		}),
+	});
+	const { success } = await verify.json();
+	if (!success) return new Response("forbidden", { status: 403 });
+
+	// process signup
+	return Response.json({ ok: true });
+};
 ```
 
 ## Variant: Astro Actions
@@ -80,11 +79,15 @@ export const server = {
 			email: z.string().email(),
 			"cf-turnstile-response": z.string(),
 		}),
-		handler: async (input) => {
-			const verify = await fetch("https://YOUR_WORKER_URL/", {
+		handler: async (input, ctx) => {
+			const verify = await fetch("https://challenges.cloudflare.com/turnstile/v0/siteverify", {
 				method: "POST",
-				headers: { "Content-Type": "application/json" },
-				body: JSON.stringify({ token: input["cf-turnstile-response"] }),
+				headers: { "Content-Type": "application/x-www-form-urlencoded" },
+				body: new URLSearchParams({
+					secret: import.meta.env.TURNSTILE_SECRET,
+					response: input["cf-turnstile-response"],
+					remoteip: ctx.clientAddress,
+				}),
 			});
 			const data = await verify.json();
 			if (!data.success) throw new Error("Verification failed");
@@ -96,7 +99,7 @@ export const server = {
 
 ## Substitutions
 
-| Placeholder        | Replace with                                |
-| ------------------ | ------------------------------------------- |
-| `YOUR_WORKER_URL`  | Deployed Worker URL from Step 5             |
-| `YOUR_SITEKEY`     | Widget site key from Step 4                 |
+| Placeholder         | Replace with                                                         |
+| ------------------- | -------------------------------------------------------------------- |
+| `YOUR_SITEKEY`      | The widget site key from Step 8                                      |
+| `YOUR_SECRET`       | The secret captured in Step 8. Stays in env, never inlined.          |

skills/turnstile-spin/references/astro.md

@@ -1,6 +1,6 @@
 # Hugo
 
-For Hugo static sites. Use a partial for the widget so it can be referenced from any layout or content file.
+For Hugo static sites. The widget renders on any page that includes the partial; siteverify happens at whatever backend handles your form submissions (a Cloudflare Pages Function, a Worker, an external API, or a form host with a server-side hook).
 
 ```html title="layouts/partials/turnstile.html"
 <script
@@ -9,12 +9,12 @@ For Hugo static sites. Use a partial for the widget so it can be referenced from
 	defer
 ></script>
 
-<form action="{{ .Site.Params.turnstileWorkerUrl }}/" method="POST">
+<form action="{{ .Site.Params.turnstileFormEndpoint }}" method="POST">
 	<input name="email" type="email" required />
 	<div
 		class="cf-turnstile"
 		data-sitekey="{{ .Site.Params.turnstileSitekey }}"
-		data-action="turnstile-spin-v1"
+		data-action="turnstile-spin-v2"
 	></div>
 	<button type="submit">Subscribe</button>
 </form>
@@ -25,7 +25,7 @@ Add the params to your site config:
 ```toml title="hugo.toml"
 [params]
 turnstileSitekey = "YOUR_SITEKEY"
-turnstileWorkerUrl = "https://YOUR_WORKER_URL"
+turnstileFormEndpoint = "/api/subscribe"  # path to your existing form handler
 ```
 
 Reference the partial from any layout or content file:
@@ -34,6 +34,38 @@ Reference the partial from any layout or content file:
 {{ partial "turnstile.html" . }}
 ```
 
+## Backend (where siteverify lives)
+
+Hugo doesn't host server-side code, so the form endpoint must live elsewhere. Two common setups:
+
+**Cloudflare Pages Function** (`functions/api/subscribe.js`):
+
+```js
+export async function onRequestPost({ request, env }) {
+	const form = await request.formData();
+	const token = form.get("cf-turnstile-response");
+
+	const r = await fetch("https://challenges.cloudflare.com/turnstile/v0/siteverify", {
+		method: "POST",
+		headers: { "Content-Type": "application/x-www-form-urlencoded" },
+		body: new URLSearchParams({
+			secret: env.TURNSTILE_SECRET,
+			response: token,
+			remoteip: request.headers.get("CF-Connecting-IP"),
+		}),
+	});
+	const { success } = await r.json();
+	if (!success) return new Response("forbidden", { status: 403 });
+
+	// process subscribe
+	return new Response("ok");
+}
+```
+
+Set the secret with `npx wrangler pages secret put TURNSTILE_SECRET` (or via the dashboard's Pages → your project → Settings → Environment variables → Add secret).
+
+**External backend**: any Node/Ruby/Python/Go handler can do the same call. See the [vanilla-html reference](./vanilla-html.md) for non-Cloudflare-specific snippets.
+
 ## Variant: shortcode for content files
 
 If you want to drop the widget into Markdown content (not just layouts), create a shortcode:
@@ -56,7 +88,8 @@ Contact us:
 
 ## Substitutions
 
-| Placeholder        | Replace with                                |
-| ------------------ | ------------------------------------------- |
-| `YOUR_WORKER_URL`  | Deployed Worker URL from Step 5             |
-| `YOUR_SITEKEY`     | Widget site key from Step 4                 |
+| Placeholder              | Replace with                                                         |
+| ------------------------ | -------------------------------------------------------------------- |
+| `YOUR_SITEKEY`           | The widget site key from Step 8                                      |
+| `turnstileFormEndpoint`  | The path or URL to your form handler (Pages Function, Worker, etc.)  |
+| `TURNSTILE_SECRET`       | Env-var name in your backend. Value is the secret captured in Step 8.|

skills/turnstile-spin/references/hugo.md

@@ -1,6 +1,6 @@
 # Next.js (App Router)
 
-For `app/`-directory Next.js projects. The widget needs to run on the client, so the page or component must be `"use client"`.
+For `app/`-directory Next.js projects. The widget needs to run on the client, so the page or component must be `"use client"`. The siteverify call lives server-side, either in a Server Action or an API route.
 
 ```tsx title="app/signup/page.tsx"
 "use client";
@@ -22,13 +22,13 @@ export default function SignupPage() {
 
 	async function handleSubmit(e: React.FormEvent<HTMLFormElement>) {
 		e.preventDefault();
-		const res = await fetch("https://YOUR_WORKER_URL/", {
+		const res = await fetch("/api/signup", {
 			method: "POST",
 			headers: { "Content-Type": "application/json" },
 			body: JSON.stringify({ token }),
 		});
 		const data = await res.json();
-		if (data.success) {
+		if (data.ok) {
 			// proceed
 		}
 	}
@@ -44,7 +44,7 @@ export default function SignupPage() {
 				<div
 					className="cf-turnstile"
 					data-sitekey="YOUR_SITEKEY"
-					data-action="turnstile-spin-v1"
+					data-action="turnstile-spin-v2"
 					data-callback="onTurnstileSuccess"
 				/>
 				<button type="submit" disabled={!token}>
@@ -58,32 +58,60 @@ export default function SignupPage() {
 
 `data-callback` expects a string referencing a global function. The `useEffect` wires `window.onTurnstileSuccess` so the widget can call back into React state.
 
+API route (canonical siteverify):
+
+```ts title="app/api/signup/route.ts"
+export async function POST(req: Request) {
+	const { token } = await req.json();
+	const remoteip = req.headers.get("x-forwarded-for") ?? undefined;
+
+	const r = await fetch("https://challenges.cloudflare.com/turnstile/v0/siteverify", {
+		method: "POST",
+		headers: { "Content-Type": "application/x-www-form-urlencoded" },
+		body: new URLSearchParams({
+			secret: process.env.TURNSTILE_SECRET!,
+			response: token,
+			...(remoteip ? { remoteip } : {}),
+		}),
+	});
+	const { success } = await r.json();
+	if (!success) return new Response("forbidden", { status: 403 });
+
+	// existing signup logic runs here
+	return Response.json({ ok: true });
+}
+```
+
 ## Variant: Server Action
 
 If you are using Server Actions, do the siteverify call from the action itself. The widget still goes in a client component, but the verify call moves server-side:
 
 ```tsx title="app/signup/actions.ts"
 "use server";
+import { headers } from "next/headers";
 
 export async function submitSignup(formData: FormData) {
 	const token = formData.get("cf-turnstile-response") as string;
+	const remoteip = (await headers()).get("x-forwarded-for") ?? undefined;
 
-	const res = await fetch("https://YOUR_WORKER_URL/", {
+	const r = await fetch("https://challenges.cloudflare.com/turnstile/v0/siteverify", {
 		method: "POST",
-		headers: { "Content-Type": "application/json" },
-		body: JSON.stringify({ token }),
+		headers: { "Content-Type": "application/x-www-form-urlencoded" },
+		body: new URLSearchParams({
+			secret: process.env.TURNSTILE_SECRET!,
+			response: token,
+			...(remoteip ? { remoteip } : {}),
+		}),
 	});
-	const data = await res.json();
-	if (!data.success) {
-		return { error: "Verification failed" };
-	}
+	const { success } = await r.json();
+	if (!success) return { error: "Verification failed" };
 
 	// process signup
 	return { ok: true };
 }
 ```
 
-```tsx title="app/signup/page.tsx"
+```tsx title="app/signup/page.tsx (server-action variant)"
 "use client";
 import { submitSignup } from "./actions";
 
@@ -94,7 +122,7 @@ export default function SignupPage() {
 			<div
 				className="cf-turnstile"
 				data-sitekey="YOUR_SITEKEY"
-				data-action="turnstile-spin-v1"
+				data-action="turnstile-spin-v2"
 			/>
 			<button type="submit">Sign up</button>
 		</form>
@@ -104,7 +132,7 @@ export default function SignupPage() {
 
 ## Substitutions
 
-| Placeholder        | Replace with                                |
-| ------------------ | ------------------------------------------- |
-| `YOUR_WORKER_URL`  | Deployed Worker URL from Step 5             |
-| `YOUR_SITEKEY`     | Widget site key from Step 4                 |
+| Placeholder         | Replace with                                                         |
+| ------------------- | -------------------------------------------------------------------- |
+| `YOUR_SITEKEY`      | The widget site key from Step 8                                      |
+| `TURNSTILE_SECRET`  | Env-var name. Value is the secret captured in Step 8, kept off disk. |