Connect from ChatGPT
3 min read
ChatGPT has one extra step vs claude.ai: enable Developer Mode first.

Prereqs
- ChatGPT Plus or Pro (Free has no Custom MCP)
- ChatGPT UI from 2025.10+ (when Developer Mode opened)
Steps
1 · Enable Developer Mode
- ChatGPT settings → Advanced
- Toggle Developer Mode on
- Reload
2 · Add Custom MCP Server
- Settings → Custom MCP servers
- "Add MCP server"
- Fill:
- Name:
Slima - Transport: HTTP / Streamable HTTP
- URL:
https://mcp.slima.ai/mcp
- Name:
- "Save"
3 · OAuth authorize
First use:
- ChatGPT prompts "Authorize with Slima"
- Redirect to Slima sign-in
- Authorize
- Redirect back
Verify
In ChatGPT:
@slima list my books
Should return your books.
ChatGPT vs Claude.ai
| claude.ai | ChatGPT | |
|---|---|---|
| Connection | Custom Connector | Custom MCP Server |
| Required tier | Pro / Max / Team / Enterprise | Plus / Pro |
| Developer Mode | No | Yes |
Issues
No Custom MCP option
- ChatGPT version ≥ 2025.10
- Plus / Pro (Free doesn't have it)
- Developer Mode on
401 / connection fails
See: Can't connect
Related
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