1. Local stdio MCP
Most reliable today. Drop krexel-mcp into ~/.codex/ or your MCP-aware tool. Works in Codex, Claude Code, Cursor, Windsurf, and VS Code right now.
Native ChatGPT connector.
OpenAI's current Apps SDK requires OAuth 2.1 with PKCE, protected-resource metadata, and authorization-server discovery. We're building that. Until it ships, ChatGPT customers have two honest options:
2. Legacy Custom GPT
A pinned OpenAPI spec for chatgpt.com customers on older plans. The tool catalogue is smaller (read-only + ship_site) and it predates the current Apps SDK.
What the native ChatGPT app will do (and won't)
- Auth. OAuth 2.1 authorization-code with PKCE. No raw API keys pasted into ChatGPT.
- Tools exposed.
list_sites,get_site,read_file,list_files,list_deploys. File write and ship tools are stubbed today and will only join the canonical hosted MCP once a unified application service (Release C) makes the corresponding operations real. - What it will not do (yet). Upload files via ChatGPT, attach a custom domain from inside ChatGPT, or run paid checkouts. Those still need the dashboard.