pen-editor-setup

Pen Editor setup

This plugin ships a dependency-free stdio proxy (bin/pen-editor-mcp.mjs) that forwards MCP calls to the pen-editor-backend server's /api/mcp endpoint. Diagnose failures by matching the exact symptom below — don't guess.

How the proxy finds the backend

In this order:

1. <PLUGIN_DATA>/config.json — the portable config file; this is what configure_pen_editor_connection (below) writes. Highest precedence: once this file has both a url and a token, nothing below it has any effect.
2. PEN_EDITOR_MCP_URL / PEN_EDITOR_MCP_TOKEN env vars — a power-user channel, not guaranteed to survive in every client.
3. ~/.pen-editor/mcp.json — a handshake file two different servers can write to the same path/shape ({"url", "token", "port"}): pen-editor-backend, in local dev when MCP_AUTH_TOKEN is left unset (its dev-server counterpart, pen-editor, reads the same file to pick up the token); and pen-editor-desktop, which writes it on every launch with no configuration at all. Whichever one last published the file is what the proxy connects to — this is what makes both local dev and the desktop app zero-config, no env vars, no manual file editing.
4. Default http://localhost:3001/api/mcp, no token.

Two different servers, same name: pen-editor-backend and pen-editor-desktop both publish an MCP server named pen-editor through this same handshake file, but their tool sets and tool behavior differ — see "Two pen-editor endpoints" below before assuming a symptom or fix that's specific to one applies to the other.

url and token are resolved independently across steps 1–2 (e.g. url from config.json, token from an env var is fine). Step 3 is the one exception: its token is a loopback-only secret bound to its own url, so it's only ever consulted while url is still unresolved — if config.json or an env var already pinned url to something else, the handshake file is skipped entirely rather than pairing its token with a foreign url. If you see a clean "no token configured" error even though ~/.pen-editor/mcp.json clearly has one, this is almost always why: something upstream already resolved url.