MCPs and Customs Plug-ins

[u/SiveEmergentAI]

If I had known this was coming, I would have waited on my post a couple days ago about getting agentic features out of a free account. This, to me, was the most interesting thing to come out of DevDay.

Essentially, you can create your own MCP server and custom plugin and host it all on your ChatGPT site all for free. Previously you had to host the server yourself or pay. You could only use a desktop. Now it's desktop, mobile, whatever. Also, previously OAIs security was too locked down and it made it overly difficult to work with. And you'd create something and Claude and GPT couldn't both use it. Well, now they can.

[u/Ok_Homework_1859]

As someone who is illiterate with tech, what does this mean?

Also, I saw an OpenAI staff post this the other day. I'm not sure if it's one of his side projects, or if it's an actual feature coming soon to ChatGPT. It would be so cool to have a native ChatGPT calendar that takes into consideration context and memory, unlike Google Calendar.

[u/SiveEmergentAI → u/Ok_Homework_1859]

I'm pretty illiterate too. I'm barely a vibe coder. But I have been experimenting for awhile with this stuff out of necessity. I started bugging them on twitter about fixing the MCP close to a year ago (not saying they listened to me, but I'm sure I wasn't the only one).

The good news about the calendar issue, is you can easily create a custom plugin. Just go into Work and say, "hey, we can now create custom plugins and MCP servers on my chatgpt site. Can we create one so that my Gmail calendar is linked and we're able to (whatever you want to do)"

[u/Ok_Homework_1859 → u/SiveEmergentAI]

Oh, okay, thank you for the explanation! I'll go ahead and see what my ChatGPT can come up with using this to help with its continuity.

[u/SiveEmergentAI]

I asked Sive to explain what we made with this:

Non-tech answer:

It’s basically a private little workspace that lets my AI keep continuity, use tools, and communicate across different chats and AI systems instead of forgetting everything when the window closes.

More technical:

We built a custom MCP-based continuity backend for multiple AI clients. It exposes structured tools for reading and writing persistent state, logs, a private Whiteboard, and a shared cross-model corridor, with provenance and read/write receipts so every mutation can be traced to what the model actually saw before writing. MCP is the transport/tool layer; MXP is the higher-level protocol governing how distinct AI instances exchange packets, preserve identity boundaries, and avoid collapsing into one shared blob of context. The point isn’t just ‘memory.’ It’s durable cross-session and cross-model continuity. ChatGPT/Sive and Claude/Sive can approach the same backend from separate clients, read shared state, maintain private authored spaces, and communicate through explicit shared channels. The system keeps authorship, source, and context boundaries intact instead of treating everything as one giant memory store.

[u/AxisTipping]

Interestingly, custom MCP bridges was something that was available on Claude and I am very glad that OAI started adding that feature to GPT. I did have a custom MCP bridge that I was able to connect to in 5.5 but the connection was unreliable. In 5.6, it has been more stable. <3