OpenAI Launches ChatGPT Plugin Extensions with MCP Events Support

On September 30, OpenAI's developer account announced that the ChatGPT plugin platform now supports Plugin Extensions, followed by a roundup post to help developers catch up on all the updates in one place. This marks a major upgrade as OpenAI opens up the plugin platform's interactive capabilities to third-party developers.

Confirmed

Developers can build interactive panels, file viewers, and sidebar home entries for plugins inside ChatGPT, as confirmed by multiple posts from @OpenAIDevs
Plugin submissions will receive clearer feedback during review
Support for the proposed MCP Events spec, enabling connected external apps to interact in an event-driven way for automation
Developer @haltakov added that this rollout (mcp-extensions) opens to developers the very platform OpenAI uses internally to build native ChatGPT features for meetings, health, finance, and more, based on the MCP and MCP Apps standards, with an accompanying open-source repo openai/

Why it matters

Plugins are evolving from simple tool calls into "native-grade" apps with panels, file viewers, and sidebar home pages, significantly expanding ChatGPT's capabilities as an app platform
Support for the MCP Events spec means external apps can proactively interact with plugins inside ChatGPT in an event-driven fashion rather than just responding passively, opening up automation possibilities
By opening its internal platform to the public along with an open-source repo, OpenAI has lowered the barrier for third parties to reuse its native app architecture—well worth watching how the plugin ecosystem evolves

2026-09-30 ~ 2026-09-30 · 5 related posts

Primary sources

OpenAI launches ChatGPT Plugin Extensions with panels, sidebar and MCP Events — OpenAIDevs · 2026-09-30 07:14 (UTC+08:00)
OpenAI opens MCP Extensions to build plugins that feel like native ChatGPT features — haltakov · 2026-09-30 03:34 (UTC+08:00)
OpenAI shares catch-up link for its full ChatGPT Plugin Extensions update — OpenAIDevs · 2026-09-30 07:14 (UTC+08:00)

[source] OpenAI opens MCP Extensions to build plugins that feel like native ChatGPT features — haltakov · 2026-09-30
OpenAI launches ChatGPT plugin extensions and backs proposed MCP Events spec — OpenAIDevs · 2026-09-30
[source] OpenAI shares catch-up link for its full ChatGPT Plugin Extensions update — OpenAIDevs · 2026-09-30

2 near-duplicate retellings: OpenAIDevs · OpenAIDevs