import { describe, expect, it } from "@effect/vitest";import { Effect } from "effect";import { Client } from "@modelcontextprotocol/sdk/client/index.js";import { InMemoryTransport } from "@modelcontextprotocol/sdk/inMemory.js";import { EXTENSION_ID, RESOURCE_MIME_TYPE } from "@modelcontextprotocol/ext-apps/server";import type { ClientCapabilities } from "@modelcontextprotocol/sdk/types.js";import { createExecutorMcpServer } from "@executor-js/host-mcp/tool-server";import { MCP_APPS_SHELL_RESOURCE_URI } from "@executor-js/host-mcp/create-artifact";import type { ExecutionEngine } from "@executor-js/execution";import { loadMcpAppsShellHtml } from "./shell-html";import { MCP_APPS_SHELL_DOCUMENT_MARKER } from "./shell-asset-path";// The shipped binary serves the shell from a file on disk (`build:shell` output,// copied next to the executable by `apps/cli/src/build.ts`). If that file is// missing the loader rejects the resource read — it used to degrade to a// placeholder document, which hung every MCP-Apps client silently — so assert// an MCP client reading the resource gets the REAL built shell. This replaces// a build-time subprocess probe that hard-slept 7 seconds inside every binary// build.const stubEngine: ExecutionEngine<never> = { execute: () => Effect.succeed({ result: "ok" }), executeWithPause: () => Effect.succeed({ status: "completed", result: { result: "ok" } }), resume: () => Effect.succeed(null), isExecutionSettled: undefined, getPausedExecution: () => Effect.succeed(null), pausedExecutionCount: () => Effect.succeed(0), hasPausedExecutions: () => Effect.succeed(false), getDescription: Effect.succeed("smoke"), // The fake forks nothing, so there is no sandbox fiber to end. shutdown: Effect.void,};// oxlint-disable-next-line executor/no-double-cast -- boundary: MCP SDK ClientCapabilities predates the ext-apps `extensions` fieldconst APPS_CAPS = { extensions: { [EXTENSION_ID]: { mimeTypes: [RESOURCE_MIME_TYPE] } },} as unknown as ClientCapabilities;describe("MCP-Apps shell resource", () => { it("serves the built shell to an MCP client", async () => { const mcpServer = await Effect.runPromise( // Artifacts are opt-in per connection; the shell resource only exists on // a session that asked for them. createExecutorMcpServer({ engine: stubEngine, loadAppShellHtml: loadMcpAppsShellHtml, artifactsEnabled: true, }), ); const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair(); const client = new Client( { name: "shell-smoke", version: "1.0.0" }, { capabilities: APPS_CAPS }, ); await mcpServer.connect(serverTransport); await client.connect(clientTransport); const read = await client.readResource({ uri: MCP_APPS_SHELL_RESOURCE_URI }); const [content] = read.contents; expect(content.mimeType).toBe(RESOURCE_MIME_TYPE); // The shell is served as text, never as a blob. expect("text" in content).toBe(true); const html = "text" in content ? content.text : ""; expect(html).toContain('id="root"'); // The identity marker the Workers loader authenticates the document by // (an ASSETS-binding miss under SPA not-found handling answers with // index.html and a 200). Asserted here so the marker leaving the template // fails this suite too, not just the app builds. expect(html).toContain(MCP_APPS_SHELL_DOCUMENT_MARKER); // `vite-plugin-singlefile` inlines every asset: a shell that still points at // a sibling bundle would 404 inside the host's sandboxed iframe. // // Scanned over the DOCUMENT only, with the inlined script bodies blanked // first. The bundle is ~5 MB of JavaScript that includes React's own source // strings, and several of those build markup as text // (`n += ' href="' + e.href + '"'` inside its resource-hint code). Matching // the raw document therefore reports tags that exist only as characters in // a string literal, which no browser will ever fetch — a false positive // that says nothing about the property under test. What matters is whether // the served document itself references anything it would have to go and // get. // Only INLINE scripts are blanked. A `<script src=...>` is exactly the // regression this guards, so its tag has to survive the blanking — matching // it and its closing tag together would delete the evidence. const documentOnly = html.replace( /<script(?![^>]*\bsrc=)[^>]*>[\s\S]*?<\/script>/g, "<script></script>", ); const externalRefs = [...documentOnly.matchAll(/<(?:script|link)[^>]*(?:src|href)="([^"]+)"/g)] .map((match) => match[1]) .filter((url) => !url.startsWith("data:")); expect(externalRefs).toEqual([]); await clientTransport.close(); await serverTransport.close(); });});
import { describe, expect, it } from "@effect/vitest";
import { Effect } from "effect";
import { Client } from "@modelcontextprotocol/sdk/client/index.js";
import { InMemoryTransport } from "@modelcontextprotocol/sdk/inMemory.js";
import { EXTENSION_ID, RESOURCE_MIME_TYPE } from "@modelcontextprotocol/ext-apps/server";
import type { ClientCapabilities } from "@modelcontextprotocol/sdk/types.js";
import { createExecutorMcpServer } from "@executor-js/host-mcp/tool-server";
import { MCP_APPS_SHELL_RESOURCE_URI } from "@executor-js/host-mcp/create-artifact";
import type { ExecutionEngine } from "@executor-js/execution";
import { loadMcpAppsShellHtml } from "./shell-html";
import { MCP_APPS_SHELL_DOCUMENT_MARKER } from "./shell-asset-path";
// The shipped binary serves the shell from a file on disk (`build:shell` output,
// copied next to the executable by `apps/cli/src/build.ts`). If that file is
// missing the loader rejects the resource read — it used to degrade to a
// placeholder document, which hung every MCP-Apps client silently — so assert
// an MCP client reading the resource gets the REAL built shell. This replaces
// a build-time subprocess probe that hard-slept 7 seconds inside every binary
// build.
const stubEngine: ExecutionEngine<never> = {
execute: () => Effect.succeed({ result: "ok" }),
executeWithPause: () => Effect.succeed({ status: "completed", result: { result: "ok" } }),
resume: () => Effect.succeed(null),
isExecutionSettled: undefined,
getPausedExecution: () => Effect.succeed(null),
pausedExecutionCount: () => Effect.succeed(0),
hasPausedExecutions: () => Effect.succeed(false),
getDescription: Effect.succeed("smoke"),
// The fake forks nothing, so there is no sandbox fiber to end.
shutdown: Effect.void,
};
// oxlint-disable-next-line executor/no-double-cast -- boundary: MCP SDK ClientCapabilities predates the ext-apps `extensions` field
const APPS_CAPS = {
extensions: { [EXTENSION_ID]: { mimeTypes: [RESOURCE_MIME_TYPE] } },
} as unknown as ClientCapabilities;
describe("MCP-Apps shell resource", () => {
it("serves the built shell to an MCP client", async () => {
const mcpServer = await Effect.runPromise(
// Artifacts are opt-in per connection; the shell resource only exists on
// a session that asked for them.
createExecutorMcpServer({
engine: stubEngine,
loadAppShellHtml: loadMcpAppsShellHtml,
artifactsEnabled: true,
}),
);
const [clientTransport, serverTransport] = InMemoryTransport.createLinkedPair();
const client = new Client(
{ name: "shell-smoke", version: "1.0.0" },
{ capabilities: APPS_CAPS },
);
await mcpServer.connect(serverTransport);
await client.connect(clientTransport);
const read = await client.readResource({ uri: MCP_APPS_SHELL_RESOURCE_URI });
const [content] = read.contents;
expect(content.mimeType).toBe(RESOURCE_MIME_TYPE);
// The shell is served as text, never as a blob.
expect("text" in content).toBe(true);
const html = "text" in content ? content.text : "";
expect(html).toContain('id="root"');
// The identity marker the Workers loader authenticates the document by
// (an ASSETS-binding miss under SPA not-found handling answers with
// index.html and a 200). Asserted here so the marker leaving the template
// fails this suite too, not just the app builds.
expect(html).toContain(MCP_APPS_SHELL_DOCUMENT_MARKER);
// `vite-plugin-singlefile` inlines every asset: a shell that still points at
// a sibling bundle would 404 inside the host's sandboxed iframe.
//
// Scanned over the DOCUMENT only, with the inlined script bodies blanked
// first. The bundle is ~5 MB of JavaScript that includes React's own source
// strings, and several of those build markup as text
// (`n += ' href="' + e.href + '"'` inside its resource-hint code). Matching
// the raw document therefore reports tags that exist only as characters in
// a string literal, which no browser will ever fetch — a false positive
// that says nothing about the property under test. What matters is whether
// the served document itself references anything it would have to go and
// get.
// Only INLINE scripts are blanked. A `<script src=...>` is exactly the
// regression this guards, so its tag has to survive the blanking — matching
// it and its closing tag together would delete the evidence.
const documentOnly = html.replace(
/<script(?![^>]*\bsrc=)[^>]*>[\s\S]*?<\/script>/g,
"<script></script>",
);
const externalRefs = [...documentOnly.matchAll(/<(?:script|link)[^>]*(?:src|href)="([^"]+)"/g)]
.map((match) => match[1])
.filter((url) => !url.startsWith("data:"));
expect(externalRefs).toEqual([]);
await clientTransport.close();
await serverTransport.close();
});
});