Crate turul_mcp_ext_apps 

MCP Apps Extension (io.modelcontextprotocol/ui, SEP-1865)

Spec-neutral host crate for the MCP-side surface of the Apps extension: UI views embedded in AI chat hosts, served by MCP servers as ui:// resources and linked from tools via _meta.ui.

Scope: this crate binds what an MCP server declares —

• the client capability shape under capabilities.extensions (UiClientCapabilities, identifier EXTENSION_IDENTIFIER)
• tool _meta.ui metadata (UiToolMeta: resourceUri, visibility)
• UI-resource _meta.ui metadata (UiResourceMeta: CSP, sandbox permissions, dedicated origin, border preference)

The host↔view iframe protocol (ui/* methods over postMessage) belongs to app/host SDKs and is deliberately not bound here.

The Apps protocol versions independently of core MCP (current: 2026-01-26); this crate’s v2026_07_28 module names the CORE spec lane it pairs with. Schema provenance: schema/README.md.

Re-exports

pub use v2026_07_28::EXTENSION_IDENTIFIER;

pub use v2026_07_28::EmptyObject;

pub use v2026_07_28::MCP_APP_HTML_MIME;

pub use v2026_07_28::META_KEY_UI;

pub use v2026_07_28::UiClientCapabilities;

pub use v2026_07_28::UiResourceCsp;

pub use v2026_07_28::UiResourceMeta;

pub use v2026_07_28::UiResourcePermissions;

pub use v2026_07_28::UiToolMeta;

pub use v2026_07_28::UiToolVisibility;

pub use v2026_07_28::client_supports_html_views;

pub use v2026_07_28::declared_by_client;

Modules

v2026_07_28

SEP-1865 Apps extension MCP-side surface for the 2026-07-28 spec line.