ChatGPT memory full? How it works and how to add Dexio
Updated
ChatGPT remembers details about you across chats, in ways OpenAI describes in its help pages. Dexio is a different kind of memory: a wiki of linked markdown pages that ChatGPT reads and writes through Developer mode, and that your other agents share. This guide covers both, including what OpenAI says about memory filling up.
What ChatGPT remembers on its own
With Memory on, ChatGPT can remember preferences and details from your chats. Depending on your plan and region, it can also draw on saved memories, custom instructions, files in Library and connected apps. It does not keep every detail; it decides what is relevant to each response.
Two settings do most of the work:
- Saved memories are details you ask ChatGPT to remember, or that it saves as useful context. They are stored apart from your chats, so deleting a chat does not delete a memory saved from it.
- Reference chat history lets ChatGPT use relevant parts of past conversations. What it keeps from them can change as ChatGPT updates what is most useful to remember.
You manage both in Settings, then Personalization, then Memory. The memory summary there is a high-level view and may leave details out. You can also ask ChatGPT what it remembers about you. Temporary chats do not create or update memories.
When memory is full
OpenAI says there is no separate storage limit for what ChatGPT can reference through chat history, so a full memory concerns saved memories. Depending on your plan, saved-memory controls include automatic prioritization, which OpenAI describes as keeping the most relevant memories in front so saved memories are less likely to reach capacity.
To make room yourself, open Settings, then Personalization, then Memory, and delete saved memories you no longer need. Deleting one stops ChatGPT using it for personalization, but it does not remove that information from past chats.
ChatGPT’s memory is context about you, kept in your ChatGPT account. A Dexio wiki holds full pages about your work: how a system works, what was decided and why, what the research found. There is no limit on the number of pages, you can read them yourself at app.dexio.wiki, and other agents read and edit the same pages.
Connect ChatGPT to Dexio
ChatGPT connects to Dexio in Developer mode only. You need chatgpt.com in a browser and a paid plan: Plus, Pro, Business, Enterprise or Education.
- In ChatGPT, open Settings, then Security and login, and turn on Developer mode.
- Open chatgpt.com/plugins and click +.
- Name it Dexio, paste
https://app.dexio.wiki/mcpand click Create. - On Dexio’s page, sign in or create a free account, then click Allow access.
- In a chat, open +, then Developer mode, then Dexio.
Dexio shows the same steps at app.dexio.wiki/settings/agents?connect=chatgpt.
Check that it works
In a chat with Dexio selected, ask:
What’s in my Dexio wiki?
ChatGPT calls Dexio’s list_pages tool and lists your pages. For actions that change data, ChatGPT may ask you to confirm first, depending on the app’s permissions and the action.
Then give it a first page to write:
Save a page in my Dexio wiki about what we’re working on. If you don’t know enough yet, ask me first.
Open app.dexio.wiki. The page shows up in the graph, where every page is a dot and every link a line.
Tell ChatGPT to use the wiki
ChatGPT takes standing instructions from two places:
- Custom instructions apply to all your chats. On the web, open Settings, then Personalization, check that Enable customization is on, and write in the Custom Instructions field. Plus, Pro, Business, Enterprise and Education plans allow up to 5,000 characters.
- Project instructions apply only within one project, and override your custom instructions there. Open the project’s ••• menu, then Project settings.
Something like this works in either:
Before answering questions about my work, search my Dexio wiki. When we settle a decision or work something out, write it to the page that covers it, and link related pages.
OpenAI’s help says choosing an app applies to the message you send it with, not the whole conversation. When a later message needs the wiki, select Dexio again or mention it by name.
Troubleshooting
- There is no Developer mode setting. It needs a paid plan and chatgpt.com in a browser. In Business, Enterprise and Education workspaces, admins control Developer mode; on Business, only admins and owners can turn it on. Ask your workspace admin. OpenAI’s help center also describes the switch under Settings, then Apps, then Advanced settings, so look there if it is not under Security and login.
- ChatGPT reads the wiki but will not write to it. OpenAI’s two descriptions differ here. Its developer docs list Plus, Pro, Business, Enterprise and Education with read and write tools. Its help center says write actions are for Business, Enterprise and Education, and that Pro connects with read and fetch only. If writes are blocked on your plan, this is the likely reason. ChatGPT also asks you to confirm write actions unless you let it remember your choice.
- ChatGPT answers without the wiki. Open +, then Developer mode, then Dexio, or mention Dexio in your message.
- You want to disconnect ChatGPT. In Dexio, Settings, then Agents lists every connected app, when each was last used, and revokes any of them.
Your other agents share the same wiki
Claude, Claude Code, Codex, Cursor, Hermes, OpenClaw and any other MCP client connect to the same wiki at the same address. Agents that can run commands set themselves up from one message. What ChatGPT writes down, Claude Code can read the next time you open a terminal.
Every agent names itself on every change, so a page’s history shows which agent wrote what, and the person behind it. Setup for each agent is in the guides, and the Claude Code guide is a good next one.
Sources
- https://developers.openai.com/api/docs/guides/developer-mode
- https://developers.openai.com/plugins/deploy/connect-chatgpt
- https://help.openai.com/en/articles/8590148-memory-in-chatgpt
- https://help.openai.com/en/articles/8096356-chatgpt-custom-instructions
- https://help.openai.com/en/articles/10169521-projects-in-chatgpt
- https://help.openai.com/en/articles/12584461-developer-mode-apps-and-full-mcp-connectors-in-chatgpt-beta
- https://dexio.wiki/docs
- https://dexio.wiki/agents.md