ext-apps/README.md
Olivier Chafik 974862237b
fix: Windows compatibility - bun as optional dep, cross-env for examples (#145)
* fix: Windows compatibility for npm scripts and cross-platform CI

Fixes #142 - Windows PowerShell install bug

Changes:
- Replace single quotes with escaped double quotes in generate:schemas
  (cmd.exe passes single quotes literally, breaking prettier glob matching)
- Simplify prettier scripts: remove redundant --ignore-path flags
  (prettier auto-loads .gitignore and .prettierignore by default)
- Remove $(pwd) from prettier scripts (bash-only syntax)
- Add cross-platform CI matrix: Linux x64, Windows x64, macOS ARM64, macOS x64
- Use shell: bash for grep commands in CI (not available in Windows cmd.exe)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: remove bun npm package from all workspaces

The bun npm package tries to install platform-specific binaries which
fails on Windows CI. Since bun is installed via oven-sh/setup-bun action
in CI (and developers install it globally), we don't need the npm package.

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Co-Authored-By: Claude <noreply@anthropic.com>

* fix: skip examples:build on Windows (uses Unix-only INPUT=... syntax)

The examples use `INPUT=mcp-app.html vite build` which is bash syntax
for setting environment variables. This doesn't work on Windows cmd.exe.
Since examples aren't published to npm, we can skip building them on Windows.

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Co-Authored-By: Claude <noreply@anthropic.com>

* fix: force LF line endings for cross-platform prettier consistency

Git on Windows auto-converts line endings to CRLF, causing prettier to
report formatting issues. Force LF for all text files.

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Co-Authored-By: Claude <noreply@anthropic.com>

* ci: add test for git-based npm install (cross-platform)

This verifies that `npm install git+https://...` works on all platforms,
which triggers the prepare script and requires bun to be available.

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Co-Authored-By: Claude <noreply@anthropic.com>

* ci: add Linux ARM64 and Windows ARM64 to CI matrix

- Added ubuntu-24.04-arm (Linux ARM64)
- Added windows-11-arm (Windows ARM64)

Note: WSL is not available on GitHub-hosted runners (requires nested
virtualization which isn't supported).

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Co-Authored-By: Claude <noreply@anthropic.com>

* ci: disable Windows ARM64 (Bun lacks stable ARM64 binaries)

The oven-sh/setup-bun action fails with 404 when trying to download
Bun for Windows ARM64. Re-enable when Bun adds proper support.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: add Windows WSL build test

Uses Vampire/setup-wsl action to install Ubuntu-24.04 in WSL and run
the full build/test cycle. This tests the Linux-in-Windows scenario
that was reported in issue #142.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: fix WSL build - install unzip for Bun installer

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Co-Authored-By: Claude <noreply@anthropic.com>

* ci: add setup-bun to publish.yml workflow

The pkg-pr-new publish workflow was missing bun setup, causing
"bun: not found" errors during npm ci (which triggers prepare script).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: enable Windows ARM64 with x64-baseline Bun (via emulation)

Windows ARM64 can run x64 binaries via emulation. Use bun-download-url
to force x64-baseline build since native ARM64 Bun isn't available yet.

Reference: https://github.com/oven-sh/bun/issues/9824

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Co-Authored-By: Claude <noreply@anthropic.com>

* ci: remove macOS x64 (macos-13 runner retired)

The macos-13 based runner images are now retired.

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Co-Authored-By: Claude <noreply@anthropic.com>

* docs: add Bun installation instructions per platform

Documents that Bun is required for development, with platform-specific
install commands in collapsible sections.

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Co-Authored-By: Claude <noreply@anthropic.com>

* docs: note Bun requirement in README examples section

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Co-Authored-By: Claude <noreply@anthropic.com>

* feat: add bun as optional dependency (no global install required)

- Add @oven/bun-* platform packages as optionalDependencies
- Create postinstall script to set up bun binary from optional deps
- Handle Windows ARM64 by downloading x64-baseline for emulation
- Remove setup-bun from CI workflows (npm install handles it now)
- Remove manual Bun install instructions from docs

This alternative approach eliminates the need for global Bun installation
or setup-bun action in CI. npm install automatically installs the
platform-appropriate bun binary.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: add debug logging to setup-bun script

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* chore: force stdout flush in setup-bun for CI debugging

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Co-Authored-By: Claude <noreply@anthropic.com>

* chore: add more debugging to setup-bun

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Co-Authored-By: Claude <noreply@anthropic.com>

* chore: remove accidental test artifacts

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Co-Authored-By: Claude <noreply@anthropic.com>

* chore: run setup-bun in prepare script (before build)

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Co-Authored-By: Claude <noreply@anthropic.com>

* feat: use cross-env for Windows-compatible example builds

- Add cross-env to devDependencies
- Update all example package.json scripts to use cross-env for INPUT and NODE_ENV
- Enable examples:build on Windows in CI (no longer Unix-only)
- Add examples:build to WSL CI job

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Co-Authored-By: Claude <noreply@anthropic.com>

* chore: remove unused imports in setup-bun.mjs

Address github-code-quality bot comments.

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Co-Authored-By: Claude <noreply@anthropic.com>

* fix: use run-bun.mjs wrapper for prepare hook compatibility

During npm install's prepare hook, node_modules/.bin is not in PATH,
so calling 'bun' directly fails. The new run-bun.mjs wrapper finds
bun at node_modules/.bin/bun and runs it with the correct path.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: restore setup-bun action for build jobs

- Add setup-bun action to build and test-git-install jobs
- Disable Windows ARM64 (Bun doesn't support this platform)
- Add bun installation to WSL build

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* fix: remove bun devDep, add libc detection for Linux ARM64

- Remove 'bun' from devDependencies (its postinstall fails on Windows ARM64)
- Add libc detection (glibc vs musl) to setup-bun.mjs
- Only try compatible binaries based on detected libc
- Re-enable Windows ARM64 in CI (now uses x64 emulation fallback)
- Remove setup-bun action from CI (no longer needed)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

* ci: simplify WSL build - let setup-bun.mjs handle bun installation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

---------

Co-authored-by: Claude <noreply@anthropic.com>
2025-12-16 14:07:38 +00:00

70 lines
3.4 KiB
Markdown

# @modelcontextprotocol/ext-apps
[![npm version](https://img.shields.io/npm/v/@modelcontextprotocol/ext-apps.svg)](https://www.npmjs.com/package/@modelcontextprotocol/ext-apps) [![API Documentation](https://img.shields.io/badge/docs-API%20Reference-blue)](https://modelcontextprotocol.github.io/ext-apps/api/)
This repo contains the SDK and [specification](https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/draft/apps.mdx) for MCP Apps Extension ([SEP-1865](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/1865)).
MCP Apps are a proposed standard inspired by [MCP-UI](https://mcpui.dev/) and [OpenAI's Apps SDK](https://developers.openai.com/apps-sdk/) to allow MCP Servers to display interactive UI elements in conversational MCP clients / chatbots.
## Overview
This SDK serves two audiences:
### App Developers
Build interactive UIs that run inside MCP-enabled chat clients.
- **SDK for Apps**: `@modelcontextprotocol/ext-apps` — [API Docs](https://modelcontextprotocol.github.io/ext-apps/api/modules/app.html)
- **React hooks**: `@modelcontextprotocol/ext-apps/react` — [API Docs](https://modelcontextprotocol.github.io/ext-apps/api/modules/_modelcontextprotocol_ext-apps_react.html)
### Host Developers
Embed and communicate with MCP Apps in your chat application.
- **SDK for Hosts**: `@modelcontextprotocol/ext-apps/app-bridge` — [API Docs](https://modelcontextprotocol.github.io/ext-apps/api/modules/app-bridge.html)
There's no _supported_ host implementation in this repo (beyond the [examples/basic-host](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) example).
We have [contributed a tentative implementation](https://github.com/MCP-UI-Org/mcp-ui/pull/147) of hosting / iframing / sandboxing logic to the [MCP-UI](https://github.com/idosal/mcp-ui) repository, and expect OSS clients may use it, while other clients might roll their own hosting logic.
## Installation
```bash
npm install -S @modelcontextprotocol/ext-apps
```
Or edit your `package.json` manually:
```json
{
"dependencies": {
"@modelcontextprotocol/ext-apps": "^0.0.1"
}
}
```
## Examples
Start with these foundational examples to learn the SDK:
- [`examples/basic-server-vanillajs`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-server-vanillajs) — Example MCP server with tools that return UI Apps (vanilla JS)
- [`examples/basic-server-react`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-server-react) — Example MCP server with tools that return UI Apps (React)
- [`examples/basic-host`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples/basic-host) — Bare-bones example of hosting MCP Apps
The [`examples/`](https://github.com/modelcontextprotocol/ext-apps/tree/main/examples) directory contains additional demo apps showcasing real-world use cases.
To run all examples together:
```bash
npm install
npm run examples:start
```
Then open http://localhost:8080/.
## Resources
- [Quickstart Guide](https://modelcontextprotocol.github.io/ext-apps/api/documents/Quickstart.html)
- [API Documentation](https://modelcontextprotocol.github.io/ext-apps/api/)
- [Draft Specification](https://github.com/modelcontextprotocol/ext-apps/blob/main/specification/draft/apps.mdx)
- [SEP-1865 Discussion](https://github.com/modelcontextprotocol/modelcontextprotocol/pull/1865)