Plenty of proxies put many servers behind one connection; what is unusual here is the state that survives the session: a document library you can ask questions of, memory sessions that compress into a summary, and a clipboard entries can be pushed to and popped from as a pipeline between tools. The trade is a dependency: everything routes through the plugged.in app, so its account holds your server configuration and its API key gates the whole connection.
A proxy that aggregates the MCP servers configured in the plugged.in app behind a single connection, routing calls to the right one. Alongside the proxying it provides its own capabilities: a document library with RAG, session memory, notifications and a clipboard.
- pluggedin_discover_tools refreshes the tool, resource and template catalogue for the configured servers, for one server or all of them, downstream servers reachable over STDIO, SSE or Streamable HTTP
- pluggedin_ask_knowledge_base answers a question from your document library and returns the answer with its document sources
- Documents created, listed, searched, updated and read: search returns metadata and a snippet, and pluggedin_get_document returns the full content and optionally its version history
- A clipboard shared between tools: entries set by name or pushed to an auto-incrementing index, popped LIFO, listed, fetched and deleted, with a content type, an encoding, a TTL and a visibility per entry, up to 2MB each
- Memory sessions: start a session, record observations with a type and an outcome as work proceeds, and end it to trigger a compressed session summary
- pluggedin_memory_search returns lightweight semantic matches and pluggedin_memory_details fetches the full content of the ones you pick — search first, expand second
- Notifications sent with a severity and optional email delivery, listed with an unread filter, marked done and deleted
- pluggedin_setup explains configuration and needs no API key, which is what makes the first connection debuggable
An account on the plugged.in app and an API key from it, passed as PLUGGEDIN_API_KEY or --pluggedin-api-key; PLUGGEDIN_API_BASE_URL points at a self-hosted instance instead of https://plugged.in. It runs as npx -y @pluggedin/pluggedin-mcp-proxy@latest, or from Docker. Default transport is stdio; --transport streamable-http serves over HTTP with --port, --require-api-auth and --stateless as the options around it. Each downstream server still needs its own credentials, configured in the plugged.in app rather than here.
One command plus a key — npx -y @pluggedin/pluggedin-mcp-proxy@latest --pluggedin-api-key YOUR_API_KEY, then supply credentials