ui: build nerdamer sandbox prelude from vendored source

tools/ui/.gitignore

@@ -36,3 +36,7 @@ static/favicon*
 *storybook.log
 storybook-static
 *.code-workspace
+
+# Vitest browser mode failure artifacts
+.vitest-attachments/
+tests/**/__screenshots__/

tools/ui/.prettierignore

@@ -16,3 +16,6 @@ build/
 /build/
 /.svelte-kit/
 test-results
+
+# Vendored third party sources, kept byte identical to upstream
+src/lib/vendors/

tools/ui/eslint.config.js

@@ -59,7 +59,8 @@ export default ts.config(
 			'.svelte-kit/**',
 			'test-results/**',
 			'.storybook/**/*',
-			'src/lib/services/sandbox-worker.js'
+			'src/lib/services/sandbox-worker.js',
+			'src/lib/vendors/**'
 		]
 	},
 	storybook.configs['flat/recommended']

tools/ui/scripts/vite-plugin-nerdamer.ts

@@ -0,0 +1,49 @@
+import { build } from 'esbuild';
+import { dirname, resolve } from 'path';
+import { fileURLToPath } from 'url';
+import type { Plugin } from 'vite';
+
+const __dirname = dirname(fileURLToPath(import.meta.url));
+
+const VENDORS_DIR = resolve(__dirname, '../src/lib/vendors');
+const VIRTUAL_ID = 'virtual:nerdamer';
+const RESOLVED_ID = '\0' + VIRTUAL_ID;
+
+/**
+ * Bundle the vendored nerdamer-prime source into a minified IIFE string,
+ * exposed as the `virtual:nerdamer` module. Flags mirror the upstream
+ * build (esbuild --bundle --minify --format=iife --global-name=nerdamer),
+ * so only human readable source lives in the repo and minification is a
+ * build artifact. Vendored under src/lib/vendors/, upstream snapshot:
+ * https://github.com/together-science/nerdamer-prime/commit/1936145f8af306ec0d883b9bfd7730aedd175c24
+ */
+export function nerdamerPlugin(): Plugin {
+	let bundled: string | null = null;
+
+	return {
+		name: 'llamacpp:nerdamer',
+		resolveId(id) {
+			return id === VIRTUAL_ID ? RESOLVED_ID : undefined;
+		},
+		async load(id) {
+			if (id !== RESOLVED_ID) return undefined;
+			if (bundled === null) {
+				const result = await build({
+					entryPoints: [resolve(VENDORS_DIR, 'nerdamer-prime/all.js')],
+					bundle: true,
+					minify: true,
+					format: 'iife',
+					globalName: 'nerdamer',
+					alias: {
+						'big-integer': resolve(VENDORS_DIR, 'big-integer/BigInteger.js'),
+						'decimal.js': resolve(VENDORS_DIR, 'decimal.js/decimal.js')
+					},
+					write: false,
+					logLevel: 'silent'
+				});
+				bundled = result.outputFiles[0].text;
+			}
+			return `export default ${JSON.stringify(bundled)};`;
+		}
+	};
+}

tools/ui/src/lib/services/sandbox-harness.ts

@@ -1,23 +1,25 @@
-/**
- * nerdamer-prime.js downloaded from https://raw.githubusercontent.com/together-science/nerdamer-prime/refs/heads/main/all.min.js
- * Upstream commit for all.min.js: https://github.com/together-science/nerdamer-prime/commit/fffcce3ebd74fefb51fcf90b613f088fcab4fd93
- */
 import { NEWLINE } from '$lib/constants';
 import WORKER_SHIM from './sandbox-worker.js?raw';
-import NERDAMER_JS from '../vendors/nerdamer-prime.js?raw';
+
+/**
+ * CSP for the harness document, inherited by the blob worker. connect-src
+ * falls back to default-src, removing network egress for model and vendored
+ * code. 'unsafe-eval' is required by the worker's AsyncFunction constructor,
+ * 'unsafe-inline' by the inline script below, worker-src by the blob worker.
+ */
+const HARNESS_CSP = `default-src 'none'; script-src 'unsafe-inline' 'unsafe-eval'; worker-src blob:`;
 
 /**
  * Harness loaded as srcdoc into a sandboxed iframe (allow-scripts only).
  * The opaque origin is the security boundary: no access to the app origin,
  * its storage or its API. The harness spawns a worker so model code never
  * runs on a main thread, which makes the parent timeout enforceable by
- * removing the iframe.
- *
- * nerdamer is preloaded in the worker, exposing the `nerdamer` global for
- * symbolic computation (simplify, derivative, integrate, solve, etc.).
+ * removing the iframe. The prelude runs in the worker before the shim,
+ * exposing globals such as `nerdamer` to model code.
  */
-export const SANDBOX_HARNESS_HTML = `<!doctype html><script>
-const SHIM = ${JSON.stringify(NERDAMER_JS + NEWLINE + WORKER_SHIM)};
+export function buildSandboxHarness(preludeJs: string): string {
+	return `<!doctype html><meta http-equiv="Content-Security-Policy" content="${HARNESS_CSP}"><script>
+const SHIM = ${JSON.stringify(preludeJs + NEWLINE + WORKER_SHIM)};
 addEventListener('message', (event) => {
 	const respond = (payload) => parent.postMessage(payload, '*');
 	let worker;
@@ -32,3 +34,4 @@ addEventListener('message', (event) => {
 	worker.postMessage({ code: event.data.code });
 });
 </script>`;
+}

tools/ui/src/lib/services/sandbox-worker.js

@@ -21,10 +21,8 @@ self.onmessage = async (event) => {
 	const reply = { logs, result: null, error: null };
 	try {
 		const AsyncFunction = Object.getPrototypeOf(async function () {}).constructor;
-		// Inject `nerdamer` (from preloaded nerdamer-prime.js) into the execution context.
-		// User code can use: nerdamer(expr), nerdamer.solve(), nerdamer.derivative(),
-		// nerdamer.integrate(), nerdamer.expand(), nerdamer.factor(), nerdamer.simplify(),
-		// nerdamer.laplace(), nerdamer.limit(), nerdamer.series(), etc.
+		// The prelude bundled ahead of this shim defines self.nerdamer,
+		// passed into the execution scope as the `nerdamer` parameter.
 		const value = await new AsyncFunction('nerdamer', event.data.code)(self.nerdamer);
 		if (value !== undefined) reply.result = fmt(value);
 	} catch (err) {

tools/ui/src/lib/services/sandbox.service.ts

@@ -7,9 +7,23 @@ import {
 	SANDBOX_TOOL_NAME,
 	SANDBOX_TRUNCATION_NOTICE
 } from '$lib/constants';
-import { SANDBOX_HARNESS_HTML } from './sandbox-harness';
+import { buildSandboxHarness } from './sandbox-harness';
 import type { ToolExecutionResult } from '$lib/types';
 
+let harnessHtml: string | null = null;
+
+/**
+ * The nerdamer prelude lives in its own lazy chunk via `virtual:nerdamer`,
+ * keeping it out of the eagerly loaded bundle. Built once per session.
+ */
+async function getHarness(): Promise<string> {
+	if (harnessHtml === null) {
+		const { default: nerdamerJs } = await import('virtual:nerdamer');
+		harnessHtml = buildSandboxHarness(nerdamerJs);
+	}
+	return harnessHtml;
+}
+
 interface SandboxReply {
 	logs?: unknown;
 	result?: unknown;
@@ -45,20 +59,22 @@ export class SandboxService {
 	 * timeout or abort. Removing the iframe terminates the worker
 	 * at the browser level, so runaway code cannot outlive it.
 	 */
-	static executeTool(
+	static async executeTool(
 		toolName: string,
 		params: Record<string, unknown>,
 		signal?: AbortSignal
 	): Promise<ToolExecutionResult> {
 		if (toolName !== SANDBOX_TOOL_NAME) {
-			return Promise.resolve({ content: `Unknown frontend tool: ${toolName}`, isError: true });
+			return { content: `Unknown frontend tool: ${toolName}`, isError: true };
 		}
 
 		const code = typeof params.code === 'string' ? params.code : '';
 		if (!code) {
-			return Promise.resolve({ content: 'Missing required parameter: code', isError: true });
+			return { content: 'Missing required parameter: code', isError: true };
 		}
 
+		const harness = await getHarness();
+
 		const requested = Number(params.timeout_ms);
 		const timeoutMs =
 			Number.isFinite(requested) && requested > 0
@@ -69,7 +85,7 @@ export class SandboxService {
 			const iframe = document.createElement('iframe');
 			iframe.setAttribute('sandbox', 'allow-scripts');
 			iframe.style.display = 'none';
-			iframe.srcdoc = SANDBOX_HARNESS_HTML;
+			iframe.srcdoc = harness;
 
 			let settled = false;