{"version":"2.1.281","anchor":"mcp-apps-host-capability-advertised-behind-claude-code-mcp-a","canonical_anchor":"mcp-apps-host-capability-advertised-behind-claude-code-mcp-a","heading":"MCP Apps host capability advertised behind CLAUDE_CODE_MCP_APPS_HOST","tier":"use","area":"MCP","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.281\/e\/mcp-apps-host-capability-advertised-behind-claude-code-mcp-a","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.281","markdown":"### MCP Apps host capability advertised behind CLAUDE_CODE_MCP_APPS_HOST\n\nWith CLAUDE_CODE_MCP_APPS_HOST set to true, Claude Code tells MCP servers it accepts MCP App content\n\n**Unclear.** The finding does not say whether Claude Code actually displays that content, or how.\n\n**What**\n\nMCP servers are outside programs that give Claude Code extra tools. When Claude Code connects to one, it describes what it can handle. When the environment variable `CLAUDE_CODE_MCP_APPS_HOST` is true, that description now includes the `io.modelcontextprotocol\/ui` extension, saying it accepts content of type `text\/html;profile=mcp-app`.\n\n**Why**\n\nA server that sees this can offer MCP App content to Claude Code. Without the variable set, nothing changes.\n\n- Area: MCP\n- Names: `CLAUDE_CODE_MCP_APPS_HOST`\n- Tier: Use it now\n- Useful: 5\/5\n- Signal: 4\/5"}