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OfficialDev Tools

MCP Apps

by Model Context Protocol

Official spec and SDK for the MCP Apps protocol. Standard for embedding UIs inside AI clients alongside MCP tools. 2,221 GitHub stars and 27 commits on main in the last 30 days.

2,221·5 tools·Released NOV 2025·NOASSERTION
npx -y @modelcontextprotocol/ext-apps
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Official spec and SDK for the MCP Apps protocol. Standard for embedding UIs inside AI clients alongside MCP tools. 2,221 stars and 27 commits on main in the last 30 days.

Reviewed by M. Nouriel · MAY 2026

INSTALL THIS SERVER

{ "mcpServers": { "mcp-apps": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/ext-apps" ] } } }
PrereqNPM: `@modelcontextprotocol/ext-apps`. Spec evolving; track release notes for breaking changes. Path: ~/Library/Application Support/Claude/claude_desktop_config.json (macOS).
{ "mcpServers": { "mcp-apps": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/ext-apps" ] } } }
{ "mcpServers": { "mcp-apps": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/ext-apps" ] } } }
{ "mcpServers": { "mcp-apps": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/ext-apps" ] } } }
{ "mcpServers": { "mcp-apps": { "command": "npx", "args": [ "-y", "@modelcontextprotocol/ext-apps" ] } } }

5 TOOLS AVAILABLE

list_apps
List installed MCP Apps in the client
Read
install_app
Install an MCP App from a manifest
Admin
render_ui
Render an MCP App UI inside the client
Admin

OUR ASSESSMENT

Strengths
  • Official Model Context Protocol project.
  • 2,221 GitHub stars.
  • 27 commits on main in the last 30 days.
  • Defines the standard for UI-embedded MCP Apps.
  • Reference SDK for both server and client implementers.
Weaknesses
  • Spec still evolving; expect breaking changes during beta phase.
  • License NOASSERTION at inspection; track for license clarification.
  • Adoption depends on MCP client support; not all clients implement the spec yet.
Security Notes

No authentication at the protocol layer. App-level security is the App author responsibility; review individual App manifests before installing in production agent flows.

Best For

MCP server authors who want to ship a UI alongside their tools; client developers implementing the MCP Apps spec; teams planning UI-rich agent experiences inside Claude Desktop, Cursor, or other MCP clients.

TECHNICAL DETAILS

Language
typescript
Transport
stdiostreamable-http
Clients
Claude DesktopClaude CodeCursorVS CodeWindsurf
License
NOASSERTION
npm
@modelcontextprotocol/ext-apps
Last Release
@modelcontextprotocol/ext-apps (npm latest)MAY 9, 2026
First Released
NOV 1, 2025

ADOPTION METRICS

// GitHub Stars
2,221

// Reading this2,221 stars on modelcontextprotocol/ext-apps. 27 commits on main in the last 30 days.

// Popularity Rank
#10
Globally · #10 in Dev Tools

// Reading thisPairs with MCP Registry, MCP Inspector, MCPB Desktop Extensions for the official MCP protocol layer.

SOURCES & VERIFICATION

We don't take any single directory's word for it. Before scoring, we cross-reference 5 public MCP sources, install the server ourselves against the clients we cover, and record when we last re-verified.

01
Discovered
Manual submission
First indexed MAY 9, 2026
02
Cross-referenced
5 directories
PulseMCP, MCP.so, Glama, Smithery, Official MCP Registry
03
Verified against
Claude Desktop
Installed and tested across clients
04
Last re-checked
MAY 9, 2026
Weekly re-verification
// How other directories see it

The same server, 5 different lenses. We reconcile these signals into our editorial score, which is why our number sometimes diverges from a directory-aggregate star count.

SourceTheir ratingTheir star countTheir downloadsLast synced
AutomationSwitch This page4.5editorial2,221MAY 9, 2026
PulseMCP— unratedunavailableunavailableMAY 9, 2026
MCP.so— unratedunavailableunavailableMAY 9, 2026
Glama— unratedunavailableunavailableMAY 9, 2026
Smithery— unratedunavailableunavailableMAY 9, 2026
Official MCP Registry— unratedunavailableunavailableMAY 9, 2026

// Counts are directory-reported; we don't adjust them. Discrepancies usually come from different snapshot times or star-caching.

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// Get in touch

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