Sumeru

configuration page
Marketplace
add mcp, minimal options
add mcp advanced options

Inspiration

MCP is everywhere: Linear, Notion, Stripe, Sentry, and dozens of local tools all speak the same protocol. But every host still wants its own config: paste another URL, wire another bearer token, fight another OAuth. I wanted one local funnel: add N upstream MCPs once, then point Codex (or any host) at a single authenticated endpoint and stop babysitting server lists.

What it does

Sumeru is a local desktop MCP funnel/manager. You add upstream servers (stdio commands like npx …, or Streamable HTTP URLs), and it exposes them through one loopback endpoint:

http://127.0.0.1:7341/mcp with bearer auth.

The host only sees three gateway tools:

list_mcps : what’s configured
list_mcp_tools : tools for a given upstream
execute_mcp_tool : call an upstream tool

Extras that make it usable day to day:

System tray lifecycle (close window → keep serving; Quit from tray to stop)
Pause / Resume and optional launch at login
Browser OAuth for HTTP MCPs (DCR when available; guided Client ID flow when not)
Secrets in the OS keychain
A Marketplace for one-click install of curated DCR providers (Notion, Linear, Stripe, Sentry, etc.)
CLI + npm launcher (sumeru-mcp) for stdio hosts and sumeru gui

How I built it

Planning phase: Gpt 5.6 sol
Desktop shell: Tauri (Rust) + Svelte 5 / Vite / shadcn-svelte
Gateway: Rust Streamable HTTP MCP server on loopback, bearer-gated, browser Origin rejected
Upstream pool: lazy connect on first tool use; reuse until edit/delete/quit; no blind retries on ambiguous failures
Transports: argv-based stdio (no shell strings) and HTTPS HTTP MCPs (plain HTTP only on loopback)
OAuth: RFC 9728 / 8414 discovery, PKCE, Dynamic Client Registration, loopback callback on :7342
Distribution: GitHub Releases (macOS/Linux), portable CLI binaries, npm sumeru-mcp, in-app VitePress docs

Challenges we ran into

MCP + OAuth issues: some providers support DCR cleanly; others need manual Client IDs, secrets, and exact redirect URIs I had to support both to ensure utility.
Tool surface bloat: dumping every upstream tool into the host breaks context; the three-tool gateway keeps the host schema small and routes intentionally

Accomplishments that we're proud of

A real product loop: install → Marketplace OAuth → paste one endpoint into Cursor → call tools
OAuth that works for both DCR and non-DCR providers, with tokens in the OS keychain
A tiny, intentional gateway API
Ship path: desktop UI, CLI/stdio mode, docs site, and release automation CI/CD

What we learned

OAuth “just works” is aspirational; discovery, DCR, and fallback UX all have to be reliable.
Local tooling works best when lifecycle is boring: tray, autostart, pause, keychain, one URL and other quality of life things.

What's next for Sumeru

Grow the Marketplace catalog and tighten non-DCR guided setup
Better observability: connection health, last-error surfaces, safer retry policy where it’s unambiguous
Smoother multi-host workflows and clearer agent-facing docs for the three gateway tools
Cross-platform polish (Windows packaging, Wayland/AppImage edges) and more cookbook recipes
Polishing macOS version of the app, it is currently untested.