ChatGPT plugins return for a third act as an Apps SDK on top of MCP
A timeline of ChatGPT plugins' three rises and falls, and how this MCP-based Apps SDK, permanent sidebar slot and MCP Events differ.
ChatGPT plugins are back for the third act in three years, and the staging this time is different enough to matter. Extensions now sit on top of your existing MCP server. OpenAI's Apps SDK wraps your tool definitions with a UI layer, so a plugin can get a permanent slot in the ChatGPT sidebar, an interactive panel next to the conversation, a native file viewer, and as of DevDay on September 29, individual permission approvals plus an MCP Events spec that lets an app start a conversation instead of waiting to be asked. A new Plugin Creator and a rebuilt submission flow are meant to fix what was, by OpenAI's own admission, an opaque review process. Here's the part that reads like deja vu with better tooling. Plugins version one launched in March 2023, the store passed 1,000 listings, and it was dead by April 2024, killed off by Custom GPTs and a GPT store that never found product market fit either. Anthropic's MCP filled the gap as the neutral protocol in November 2024. OpenAI adopted it by March 2025, shipped the Apps SDK with Spotify, Canva and http://Booking.com as launch partners that October, reopened the plugin directory on July 9 this year, and DevDay just made the sidebar slot permanent with Slack, SharePoint, Airtable and Google Drive already wired in. The best proof of life isn't a launch partner logo. Within a day of the keynote, Federico Viticci shipped a free, open source extension that puts Apple Reminders inside ChatGPT, built on his own RemCTL command line tool with full MCP support. What nobody's pricing in: OpenAI still says it periodically compares your MCP server's tools against the published definitions. The platform keeps veto power over ranking and surface area, the same leverage that made the first plugin store a ghost town the moment ChatGPT's own features covered the obvious use cases. The protocol layer is open now. The shelf space still isn't. https://x.com/viticci/status/2105318261898322344
This post quotes another post: “RemCTL 2.0 runs Apple Reminders as a ChatGPT extension”