--- title: "Use WhatsApp in ChatGPT through a custom MCP app" description: "Add Kaption’s WhatsApp MCP server to ChatGPT as an app with developer mode. ChatGPT can search chats, summarize conversations and set reminders." canonical: "https://kaptionai.com/mcp/chatgpt/" lang: "en" --- # Use WhatsApp in ChatGPT through a custom MCP app > Add Kaption’s WhatsApp MCP server to ChatGPT as an app with developer mode. ChatGPT can search chats, summarize conversations and set reminders. Canonical: https://kaptionai.com/mcp/chatgpt/ ChatGPT can connect to remote MCP servers with OAuth sign-in. Add Kaption’s server and ask ChatGPT to search your chats, summarize a group or find a contact. ## Ask ChatGPT about your WhatsApp ChatGPT reads the answer from your WhatsApp through Kaption on your computer. Kaption’s relay checks your sign-in and cannot read your messages. ## How to connect 1. **Turn on Cloud MCP in Kaption.** Open WhatsApp Web in Chrome or Edge with the Kaption extension, then AI assistants (MCP) › Cloud Bridge › Enable. In the Kaption desktop app, switch on Cloud MCP in Settings. In Kaption 0.95 and later, open AI assistants (MCP), click Add an assistant and choose Claude or ChatGPT. Keep Kaption open while the assistant works: the tools only reach WhatsApp while Kaption runs. 2. **Turn on developer mode in ChatGPT.** Open ChatGPT Settings › Apps (Connectors on some plans) › Advanced settings and turn on Developer mode. The menu names vary by plan; OpenAI’s help center has the current path. 3. **Create the app.** Click Create (or Add custom connector), name it WhatsApp, paste the address below and choose OAuth as the authentication. 4. **Sign in with a code on WhatsApp.** The app opens Kaption’s sign-in page. Enter your phone number, type the 6-digit code Kaption sends you on WhatsApp, and choose how long the connection lasts: while you use it (it ends after 90 days without use), 1 year, or until you disconnect it. MCP server address: `https://mcp.kaptionai.com/mcp` (Streamable HTTP, OAuth 2.1). ## Good to know - **ChatGPT plans:** Custom MCP apps depend on your ChatGPT plan and workspace settings, and OpenAI changes them often. If you don’t see developer mode, ask your workspace admin or check OpenAI’s help center. - **Turn it on in a chat:** Pick the WhatsApp app from the tools menu in a conversation, then ask about your chats. - **What ChatGPT can do:** Search and read chats, summarize conversations, look up contacts and groups, manage labels, notes and reminders, and schedule a message after you confirm it. ## Plan and limits Claude and ChatGPT are unlimited in every account’s first 60 days; after that they need a plan: Lifetime local AI 20 actions a week, Pro 250 credits a month, and Business 500 with its 2 numbers plus 250 for each extra number, shared by all its numbers, the plan to pick when an assistant uses WhatsApp every day. Business Agent includes them with fair use. A read uses 1 credit, a send 2 and a summary 3. Prices: https://kaptionai.com/pricing/ ([pricing.md](https://kaptionai.com/pricing.md)). ## Questions ### Can the assistant send messages on its own? Yes, unless you turn it off. Sending from your computer is on by default, and Kaption tells you the first time an assistant sends. The assistant can send to an existing person chat or an eligible group, with one attachment up to 8 MiB. The message is queued for the earliest permitted delivery, within 8 an hour and 20 a day, and your computer and WhatsApp must stay open. To stop it, turn off “Let assistants send messages from this computer” in Kaption → AI assistants (MCP) → Connections; the assistant cannot turn it back on. With it off, the assistant can still schedule one message to one 1:1 chat, up to 800 characters. Either way, it should confirm the text and the recipient with you first. Locked chats are never visible to it. ### Does Kaption store my chats on its servers? No. The relay at mcp.kaptionai.com checks your sign-in and passes each request to Kaption on your computer, which runs it against your WhatsApp and sends back only the answer. ### What does “Extension not connected” mean? Kaption is closed, or Cloud MCP is off. Open WhatsApp Web with the Kaption extension, or the desktop app, and turn the connection on.