From 28a21c5e08c8529416ac92ec64a069310c45ee3c Mon Sep 17 00:00:00 2001 From: cliffhall Date: Wed, 5 Aug 2026 17:59:09 -0400 Subject: [PATCH] test: add an MCP App showcase config to reproduce and verify #1859 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The `mcp_app_demo` tool and `mcp_app_demo_widget` UI resource presets already existed in the preset registry, but no config wired them into a server — so there was no runnable way to reach a rendered MCP App, and therefore no way to exercise the sandbox proxy path that #1859 broke. `mcp-app-http.json` composes the two over plain streamable-HTTP. With it, the Apps tab renders a real widget and the packaging bug is reproducible on demand: without clients/web/static in the tarball the widget area shows "Sandbox not loaded: ENOENT … /clients/web/static/sandbox_proxy.html" instead. Co-Authored-By: Claude Opus 5 (1M context) Claude-Session: https://claude.ai/code/session_01XAR2Nr9kXbrywFNUVoTe9F --- README.md | 9 +++++++++ test-servers/configs/mcp-app-http.json | 12 ++++++++++++ 2 files changed, 21 insertions(+) create mode 100644 test-servers/configs/mcp-app-http.json diff --git a/README.md b/README.md index 5a5d7a2f..05ffe096 100644 --- a/README.md +++ b/README.md @@ -132,6 +132,7 @@ Each config below is a ready-made server for exercising one feature by hand. Loa | Config | Demonstrates | Issue | | ----------------------------------------- | -------------------------------------------------- | ---------------------------------------------------------------------- | +| `mcp-app-http.json` | An MCP App (UI resource + app tool) in the Apps tab | [#1859](https://github.com/modelcontextprotocol/inspector/issues/1859) | | `modern-mrtr-http.json` | A single MRTR round-trip | — | | `mrtr-showcase-http.json` | Every MRTR preset in one server | — | | `modern-network-http.json` | Network tab: `Mcp-*` headers + error taxonomy | [#1628](https://github.com/modelcontextprotocol/inspector/issues/1628) | @@ -142,6 +143,14 @@ Each config below is a ready-made server for exercising one feature by hand. Loa | `subscriptions-{legacy,modern}-http.json` | Resource subscriptions, both eras | [#1630](https://github.com/modelcontextprotocol/inspector/issues/1630) | | `tasks-{legacy,modern}-http.json` | Tasks, both eras | [#1631](https://github.com/modelcontextprotocol/inspector/issues/1631) | +#### MCP Apps + +`mcp-app-http.json` serves the `mcp_app_demo` tool (`_meta.ui.resourceUri`) alongside its `mcp_app_demo_widget` UI resource, so the **Apps** tab has a real App to render. It is a plain streamable-HTTP server — connect with the **default (legacy)** protocol era, not Modern. + +Open the Apps tab, select `mcp_app_demo`, give it a title and click **Open App**: the widget renders inside the sandbox iframe and exercises the host-side UI protocol surface — host-context render, `size-changed`, `ui/message`, and a log line into the **App logs** panel. Because the widget is served through the sandbox proxy page, this config is also what reproduces [#1859](https://github.com/modelcontextprotocol/inspector/issues/1859) (a missing `clients/web/static/sandbox_proxy.html` surfaces here as a "Sandbox not loaded" message in place of the widget) — a failure that only ever appeared in an installed package, never in the repo. + +For the scripted version of the same flow (`--app-info` probe → deep link → rendered widget), see [Reviewing an MCP App](./docs/mcp-app-review.md). + #### MRTR `modern-mrtr-http.json` serves the `mrtr_confirm` tool (preset `mrtr_confirm`, `createMrtrTool`) over the modern leg. Its handler returns `inputRequired(...)` embedding a form elicitation, so invoking it produces a real round-trip: `input_required` → the client fulfils the embedded elicitation and retries with a new id → `complete`. diff --git a/test-servers/configs/mcp-app-http.json b/test-servers/configs/mcp-app-http.json new file mode 100644 index 00000000..445966ac --- /dev/null +++ b/test-servers/configs/mcp-app-http.json @@ -0,0 +1,12 @@ +{ + "serverInfo": { + "name": "mcp-app-showcase", + "version": "1.0.0" + }, + "tools": [{ "preset": "echo" }, { "preset": "mcp_app_demo" }], + "resources": [{ "preset": "mcp_app_demo_widget" }], + "transport": { + "type": "streamable-http", + "port": 3130 + } +}