{
  "title": "MCP Apps vs MCP-UI",
  "schemaVersion": "1.0",
  "researchFreeze": "2026-08-26",
  "protocolRevision": "MCP Apps 2026-01-26 / ext-apps SDK v1.7.5 / MCP core 2026-07-28",
  "sourcePackage": "research/9",
  "integrityNote": "The 93 ordinary archive entries verify. Two self-referential bookkeeping entries have disclosed stale final rows; public corrections do not modify the raw archive.",
  "count": 10,
  "records": [
    {
      "Dimension": "Historical role",
      "MCP-UI": "Pre-standard community implementation and experimentation",
      "MCP Apps": "Official standardized extension",
      "id": "R9-MCPUI001",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Current role",
      "MCP-UI": "SDKs and adapters that implement MCP Apps plus legacy compatibility",
      "MCP Apps": "Normative protocol and official SDK",
      "id": "R9-MCPUI002",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Primary tool linkage",
      "MCP-UI": "Legacy formats and current _meta.ui.resourceUri",
      "MCP Apps": "_meta.ui.resourceUri",
      "id": "R9-MCPUI003",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "View transport",
      "MCP-UI": "MCP-UI postMessage conventions and adapters",
      "MCP Apps": "JSON-RPC App protocol over postMessage",
      "id": "R9-MCPUI004",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Host SDK",
      "MCP-UI": "@mcp-ui/client is a production-oriented host renderer",
      "MCP Apps": "Official repo offers AppBridge/basic-host, not a turnkey host product",
      "id": "R9-MCPUI005",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "OpenAI compatibility",
      "MCP-UI": "Current ChatGPT UI builds target MCP Apps; adapters can cover optional ChatGPT-specific extensions such as window.openai.",
      "MCP Apps": "The open standard is now OpenAI’s baseline for new ChatGPT UI, with product extensions remaining optional.",
      "id": "R9-MCPUI006",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413",
        "S417"
      ],
      "packageSnapshot": {
        "mcpUi": "Apps SDK adapter translates to window.openai",
        "mcpApps": "Open standard differs from OpenAI-specific runtime"
      },
      "editorialCorrection": "Updated the stale adapter-only framing to OpenAI’s current MCP Apps-first UI guidance."
    },
    {
      "Dimension": "Migration",
      "MCP-UI": "Adapters can preserve legacy widgets while adopting official metadata",
      "MCP Apps": "New implementations should target stable Apps spec",
      "id": "R9-MCPUI007",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Relationship",
      "MCP-UI": "Influenced and helped author the standard",
      "MCP Apps": "Formalized a cross-host baseline",
      "id": "R9-MCPUI008",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Same project?",
      "MCP-UI": "No, but closely related and overlapping contributors",
      "MCP Apps": "No, official MCP extension project",
      "id": "R9-MCPUI009",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    },
    {
      "Dimension": "Recommended wording",
      "MCP-UI": "MCP-UI pioneered and now implements MCP Apps",
      "MCP Apps": "MCP Apps is the standardized extension",
      "id": "R9-MCPUI010",
      "packageSourceIds": [
        "S001",
        "S004",
        "S032",
        "S033"
      ],
      "sourceIds": [
        "S388",
        "S390",
        "S412",
        "S413"
      ]
    }
  ]
}