John's Essentials for ChatGPT

com.johnsessentials/johns-essentials

144 deterministic file tools: PDF, image, media, convert, analyze. Connect in one click (OAuth).

client:ChatGPT transport:streamable-http

Install John's Essentials in ChatGPT

Settings → Connectors → Advanced → Developer mode

https://api.johnsessentials.com/mcp/messages

Custom connectors are a paid-plan feature and take a remote URL only. ChatGPT cannot run a packaged server locally. ChatGPT docs