Apps SDK changelog

ChatGPT now provides standardized MCP Apps host CSS variables through hostContext.styles.variables during initialization and updates them through ui/notifications/host-context-changed when the host theme changes, helping apps match ChatGPT’s light and dark appearance without hardcoded host-specific colors.

window.openai.toolResponseMetadata now preserves the canonical MCP tool result envelope, including hidden _meta, when ChatGPT launches widgets.

For tools that need user approval, ChatGPT now delivers widget tool input through the MCP Apps ui/notifications/tool-input lifecycle after approval instead of preloading it into the initial widget globals.

ChatGPT now reads MCP server instructions returned during initialization and uses them alongside tool metadata to understand cross-tool workflows, constraints, and server-wide guidance.

Apps SDK and MCP server docs now show outputSchema in tool examples and recommend declaring one for tools that return structured content.

Apps SDK docs now explain that OpenAI turns approved apps into plugins for Codex distribution, and that for now plugins are only available in Codex.

window.openai.selectFiles() lets widgets pick existing files from the user’s ChatGPT file library when that library is available.

window.openai.uploadFile(file, { library: true }) lets widgets save uploads into the user’s ChatGPT file library when that library is available.

window.openai.uploadFile now supports non-image file types.

ChatGPT is now fully compatible with the MCP Apps spec.

window.openai.openExternal({ href, redirectUrl }) supports redirectUrl: false, which prevents the host from appending ?redirectUrl=... to external links.

window.openai.setOpenInAppUrl({ href }) is the supported way to override the fullscreen “Open in ” destination; if you do not call it, ChatGPT keeps opening the widget’s current iframe path.

openai/widgetDescription is honored during resource construction and takes precedence over resource.description when present.

window.openai.sendFollowUpMessage supports a scrollToBottom parameter; it defaults to true, and you can pass false to opt out.

Added company knowledge in ChatGPT compatibility guidance for the search/fetch tools. Click here to learn more.

Tool calls now include _meta["openai/session"], an anonymized conversation id you can use to correlate requests within a ChatGPT session.

window.openai.requestModal({ template }) now supports opening a different registered UI template by passing the template URI from registerResource.

Published a new Apps SDK state management guide.

Added copy functionality to all code snippets.

Launched a unified developers changelog.