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@optilogic/mcp-ui

v0.2.1

Published

MCP Apps UI bridge for Optilogic widgets - postMessage host client, React hooks, and WidgetRoot for building sandboxed opti-ui widgets embedded in Claude

Downloads

285

Vulnerabilities

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Links

Git

Maintainers

optishanedevoptishanedevjust-zachjust-zachopti-johnnyopti-johnny

Keywords

reactmcpmcp-uimcp-appspostmessagewidgetsoptilogic

Readme

@optilogic/mcp-ui

The bridge for building MCP Apps widgets — self-contained HTML UIs that Claude (and other MCP hosts) embed in a sandboxed iframe. It handles the boring, spec-defined parts so a widget is just an opti-ui component plus a data hook:

  • Host client — a typed postMessage / JSON-RPC transport that speaks the MCP Apps app↔host protocol (handshake, render-data delivery, tool callbacks, host context).
  • React hooks — useMcpData() (the tool's render data), useHostTheme() (host light/dark → opti-ui theme), useCallTool() (call a server tool back through the host).
  • <WidgetRoot> — wraps a widget: runs the handshake, injects @optilogic/core styles + theme, and renders loading / error states so every widget doesn't re-solve them.
  • @optilogic/mcp-ui/testing — a mock host for developing and Storybook-testing widgets offline, with no MCP host in the loop.

Widgets themselves live in the server that owns their tool data contracts (e.g. opti-mcp/web/widgets/*), not here. This package ships the reusable plumbing + the components they render come from @optilogic/charts / @optilogic/core.

Trust boundary

Everything arriving over postMessage is untrusted input. The transport validates every inbound message with hand-written type guards (unknown → narrowed) before it reaches widget code — never a cast. See src/protocol/.

Status

Foundation phase (opti-ui-foundation). The wire contract is being reconciled against the live MCP Apps spec; the transport's message format is isolated in src/protocol/ as the single swap-point.