Photon Weather ChatGPT MCP compatibility proof
Generated from a local OpenAI-style MCP probe against:

  PHOTON_DIR=examples/weather-showcase
  node dist/cli.js mcp weather --transport sse --port 3479

The probe used a ChatGPT-like initialize payload:

  clientInfo.name: openai-mcp
  clientInfo.version: 1.0.0
  protocolVersion: 2025-11-25
  extensions.io.modelcontextprotocol/ui.mimeTypes:
    - text/html;profile=mcp-app

Observed MCP evidence:

  initialize.status: 200
  initialize.server.name: photon-mcp
  initialize.protocolVersion: 2025-11-25

  tools/list:
    tool.name: current
    tool.annotations.readOnlyHint: true
    tool._meta.ui.resourceUri: ui://weather/weather-card
    tool._meta.outputTemplate: ui://weather/weather-card
    tool._meta.openai/outputTemplate: ui://weather/weather-card
    tool._meta.openai/widgetAccessible: true
    tool._meta.photon/render.resources.ui: ui://weather/weather-card

  resources/list:
    resource.uri: ui://weather/weather-card
    resource.name: ui:weather-card
    resource.description: UI template for current tool
    resource.mimeType: text/html;profile=mcp-app

  resources/read:
    status: 200
    content.uri: ui://weather/weather-card
    content.mimeType: text/html;profile=mcp-app
    content._meta.ui.prefersBorder: true
    content._meta.openai/widgetDescription: Interactive weather UI rendered from Photon.
    content._meta.openai/widgetPrefersBorder: true
    content.text includes: Photon weather showcase

Post-ChatGPT compatibility fix:

  openai-mcp without an explicit UI capability now receives the same UI tool
  descriptor metadata:

    tool._meta.ui.resourceUri: ui://weather/weather-card
    tool._meta.openai/outputTemplate: ui://weather/weather-card

  These resource reads now resolve to the same app card:

    ui://weather/weather-card
    ui://weather/current
    weather/current

Live ChatGPT note:

  In a developer-mode ChatGPT session, ChatGPT connected to the temporary
  Cloudflare Tunnel endpoint, listed slashless tools (`current`, `cities`),
  called `current` with city Singapore, fetched ui://weather/weather-card, and
  rendered the embedded weather app iframe inline. The screenshot is checked in
  at assets/showcase/weather/chatgpt-photon-weather-local-dot.png.
  A clean-flow capture shows the named Photon Weather Showcase connector
  rendering Singapore from a fresh prompt at
  assets/showcase/weather/chatgpt-photon-weather-clean-flow.gif.