A field note · ~6 min read
ChatGPT memory over MCP
Every complaint about ChatGPT's memory comes down to the same constraint: it has to fit inside the prompt of every conversation, so it has to be tiny. MCP sidesteps the constraint entirely. The model stops carrying you around and starts looking you up.
Carrying versus querying
Built-in memory is carried. Every saved fact is injected into every conversation whether it is relevant or not, which is exactly why it has to stay around 1,200–2,000 tokens. Multiply a larger bucket by hundreds of millions of users and the arithmetic stops working.
An MCP memory server is queried. Nothing is injected up front. When the model needs to know how you like documents structured, it calls a tool and asks. Cost scales with relevance rather than with the size of your history, which is why the ceiling effectively disappears.
What that changes in practice
| | Built-in memory | MCP memory server |
|---|
| Size | ~8–12 short facts | No practical ceiling |
| Setup | None | Developer mode plus a URL |
| Exportable | No | Yes — it is your store |
| Works in Claude too | No | Yes, same server |
| Survives a model change | Not guaranteed | Yes |
| Works on mobile | Yes | No — web only |
That last row is a real limitation, not a footnote. Developer mode is web-only, so an MCP-backed memory does not follow you to the phone. For most people the honest answer is to use both: built-in memory for the handful of facts that should always be present, MCP for the depth.
Getting there
Enable Developer mode, add https://konshus.ai/api/mcp, sign in. Full walkthrough in how to add an MCP connector to ChatGPT.
A vault only helps if there is something in it, so the useful first move is usually importing your existing history rather than starting from a blank page — see how to back up ChatGPT.