| --- |
| title: Universal MCP Hub - Volkan |
| emoji: 🛡️ |
| colorFrom: indigo |
| colorTo: red |
| sdk: docker |
| pinned: false |
| license: apache-2.0 |
| short_description: 'Sandboxed Universal MCP Server built on PyFundaments' |
| --- |
| |
| # Universal MCP Hub (Sandboxed) |
|
|
| > A production-grade MCP server that actually thinks about security. |
| > Built on [PyFundaments](PyFundaments.md) — running on **simpleCity** and **paranoidMode**. |
|
|
| ``` |
| No key → no tool → no crash → no exposed secrets |
| ``` |
|
|
| Most MCP servers are prompts dressed up as servers. This one has a real architecture. |
|
|
| --- |
|
|
| ## Why this exists |
|
|
| First have a look on this new project from BadTin & Me [Wall-of-Shames](https://github.com/Wall-of-Shames?view_as=public) |
|
|
| The MCP ecosystem is full of servers with hardcoded keys, zero sandboxing, and `os.environ` scattered everywhere. One misconfigured fork and your API keys are gone. |
|
|
| This hub was built as the antidote: |
|
|
| - **Structural sandboxing** — `app/*` can never touch `fundaments/` or `.env`. Not by convention. By design. |
| - **Guardian pattern** — `main.py` is the only process that reads secrets. It injects validated services as a dict. `app/*` never sees the raw environment. |
| - **Graceful degradation** — No key? Tool doesn't register. Server still starts. No crash, no error, no empty `None` floating around. |
| - **Single source of truth** — All tool/provider/model config lives in `app/.pyfun`. Adding a provider = edit one file. No code changes. |
|
|
| --- |
|
|
| ## Architecture |
|
|
| ``` |
| main.py (Guardian) |
| │ |
| │ reads .env / HF Secrets |
| │ initializes fundaments/* conditionally |
| │ injects validated services as dict |
| │ |
| └──► app/app.py (Orchestrator, sandboxed) |
| │ |
| │ unpacks fundaments ONCE, at startup, never stores globally |
| │ starts hypercorn (async ASGI) |
| │ routes: GET / | POST /api | GET+POST /mcp |
| │ |
| ├── app/mcp.py ← FastMCP + SSE handler |
| ├── app/tools.py ← Tool registry (key-gated) |
| ├── app/provider.py ← LLM + Search execution + fallback chain |
| ├── app/models.py ← Model limits, costs, capabilities |
| ├── app/config.py ← .pyfun parser (single source of truth) |
| └── app/db_sync.py ← Internal SQLite IPC (app/* state only) |
| ≠ fundaments/postgresql.py (Guardian-only) |
| ``` |
|
|
| **The sandbox is structural:** |
|
|
| ```python |
| # app/app.py — fundaments are unpacked ONCE, NEVER stored globally |
| async def start_application(fundaments: Dict[str, Any]) -> None: |
| config_service = fundaments["config"] |
| db_service = fundaments["db"] # None if not configured |
| encryption_service = fundaments["encryption"] # None if keys missing |
| access_control_service = fundaments["access_control"] |
| ... |
| # From here: app/* reads its own config from app/.pyfun only. |
| # fundaments are never passed into other app/* modules. |
| ``` |
|
|
| `app/app.py` never calls `os.environ`. Never imports from `fundaments/`. Never reads `.env`. |
| This isn't documentation. It's enforced by the import structure. |
|
|
| ### Why Quart + hypercorn? |
|
|
| MCP over SSE needs a proper async HTTP stack. The choice here is deliberate: |
|
|
| **Quart** is async Flask — same API, same routing, but fully `async/await` native. This matters because FastMCP's SSE handler is async, and mixing sync Flask with async MCP would require thread hacks or `asyncio.run()` gymnastics. With Quart, the `/mcp` route hands off directly to `mcp.handle_sse(request)` — no bridging, no blocking. |
|
|
| **hypercorn** is an ASGI server (vs. waitress/gunicorn which are WSGI). WSGI servers handle one request per thread — fine for traditional web apps, wrong for SSE where a connection stays open for minutes. hypercorn handles SSE connections as long-lived async streams without tying up threads. It also runs natively on HuggingFace Spaces without extra config. |
|
|
| The `/mcp` route in `app.py` is also the natural interception point — auth checks, rate limiting, payload logging can all be added there before the request ever reaches FastMCP. That's not possible when FastMCP runs standalone. |
|
|
| --- |
|
|
| ## Two Databases — One Architecture |
|
|
| This hub runs **two completely separate databases** with distinct responsibilities. This is not redundancy — it's a deliberate performance and security decision. |
|
|
| ``` |
| ┌─────────────────────────────────────────────────────────────┐ |
| │ Guardian Layer (fundaments/*) │ |
| │ │ |
| │ postgresql.py → Cloud DB (e.g. Neon, Supabase) │ |
| │ asyncpg pool, SSL enforced │ |
| │ Neon-specific quirks handled │ |
| │ (statement_timeout stripped, keepalives) │ |
| │ │ |
| │ user_handler.py → SQLite (users + sessions tables) │ |
| │ PBKDF2-SHA256 password hashing │ |
| │ Session validation incl. IP + UserAgent │ |
| │ Account lockout after 5 failed attempts │ |
| │ Path: SQLITE_PATH env var or app/ │ |
| │ │ |
| └──────────────────────┬──────────────────────────────────────┘ |
| │ inject as fundaments dict |
| ▼ |
| ┌─────────────────────────────────────────────────────────────┐ |
| │ App Layer (app/*) │ |
| │ │ |
| │ db_sync.py → SQLite (hub_state + tool_cache tables) │ |
| │ aiosqlite (async, non-blocking) │ |
| │ NEVER touches users/sessions tables │ |
| │ Relocated to /tmp/ on HF Spaces auto │ |
| │ │ |
| └─────────────────────────────────────────────────────────────┘ |
| ``` |
|
|
| **Why two SQLite databases?** |
|
|
| `user_handler.py` (Guardian) owns `users` and `sessions` — authentication state that must be isolated from the app layer. `db_sync.py` (app/*) owns `hub_state` and `tool_cache` — fast, async IPC between tools that doesn't need to leave the process, let alone hit a cloud endpoint. |
| |
| A tool caching a previous LLM response or storing intermediate state between pipeline steps should never wait on a round-trip to Neon. Local SQLite is microseconds. Cloud PostgreSQL is 50-200ms per query. For tool-to-tool communication, that difference matters. |
| |
| **Table ownership — hard rule:** |
| |
| | Table | Owner | Access | |
| | :--- | :--- | :--- | |
| | `users` | `fundaments/user_handler.py` | Guardian only | |
| | `sessions` | `fundaments/user_handler.py` | Guardian only | |
| | `hub_state` | `app/db_sync.py` | app/* only | |
| | `tool_cache` | `app/db_sync.py` | app/* only | |
|
|
| `db_sync.py` uses the same SQLite path (`SQLITE_PATH`) as `user_handler.py` — same file, different tables, zero overlap. The `db_query` MCP tool exposes SELECT-only access to `hub_state` and `tool_cache`. It cannot reach `users` or `sessions`. |
|
|
| **Cloud DB (postgresql.py):** |
|
|
| Handles the heavy cases — persistent storage, workflow tool results that need to survive restarts, anything that benefits from a real relational DB. Neon-specific quirks are handled automatically: `statement_timeout` is stripped from the DSN (Neon doesn't support it), SSL is enforced at `require` minimum, keepalives are set, and terminated connections trigger an automatic pool restart. |
|
|
| If no `DATABASE_URL` is set, the entire cloud DB layer is skipped cleanly. The app runs without it. |
|
|
| --- |
|
|
| ## Tools |
|
|
| Tools register themselves at startup — only if the required API key exists in the environment. No key, no tool. The server always starts. |
|
|
| | ENV Secret | Tool | Notes | |
| | :--- | :--- | :--- | |
| | `ANTHROPIC_API_KEY` | `llm_complete` | Claude Haiku / Sonnet / Opus | |
| | `GEMINI_API_KEY` | `llm_complete` | Gemini 2.0 / 2.5 / 3.x Flash & Pro | |
| | `OPENROUTER_API_KEY` | `llm_complete` | 100+ models via OpenRouter | |
| | `HF_TOKEN` | `llm_complete` | HuggingFace Inference API | |
| | `BRAVE_API_KEY` | `web_search` | Independent web index | |
| | `TAVILY_API_KEY` | `web_search` | AI-optimized search with synthesized answers | |
| | `DATABASE_URL` | `db_query` | Read-only SELECT — enforced at app level | |
| | *(always)* | `list_active_tools` | Shows key names only — never values | |
| | *(always)* | `health_check` | Status + uptime | |
| | *(always)* | `get_model_info` | Limits, costs, capabilities per model | |
|
|
| **Configured in `.pyfun` — not hardcoded:** |
|
|
| ```ini |
| [TOOL.code_review] |
| active = "true" |
| description = "Review code for bugs, security issues and improvements" |
| provider_type = "llm" |
| default_provider = "anthropic" |
| timeout_sec = "60" |
| system_prompt = "You are an expert code reviewer. Analyze the given code for bugs, security issues, and improvements. Be specific and concise." |
| [TOOL.code_review_END] |
| ``` |
|
|
| Current built-in tools: `llm_complete`, `code_review`, `summarize`, `translate`, `web_search`, `db_query` |
| Future hooks (commented, ready): `image_gen`, `code_exec`, `shellmaster`, Discord, GitHub webhooks |
|
|
| --- |
|
|
| ## LLM Fallback Chain |
|
|
| All LLM providers share one `llm_complete` tool. If a provider fails, the hub automatically walks the fallback chain defined in `.pyfun`: |
|
|
| ``` |
| anthropic → gemini → openrouter → huggingface |
| ``` |
|
|
| Fallbacks are configured per-provider, not hardcoded: |
|
|
| ```ini |
| [LLM_PROVIDER.anthropic] |
| fallback_to = "gemini" |
| [LLM_PROVIDER.anthropic_END] |
| |
| [LLM_PROVIDER.gemini] |
| fallback_to = "openrouter" |
| [LLM_PROVIDER.gemini_END] |
| ``` |
|
|
| Same pattern applies to search providers (`brave → tavily`). |
|
|
| --- |
|
|
| ## Quick Start |
|
|
| ### HuggingFace Spaces (recommended) |
|
|
| 1. Fork / duplicate this Space |
| 2. Go to **Settings → Variables and secrets** |
| 3. Add the API keys you have (any subset works) |
| 4. Space starts automatically — only tools with valid keys register |
|
|
| That's it. No config editing. No code changes. |
|
|
| [→ Live Demo Space](https://huggingface.co/spaces/codey-lab/Universal-MCP-Hub-DEMO) (no LLM keys set!) |
|
|
| ### Local / Docker |
|
|
| ```bash |
| git clone https://github.com/VolkanSah/Universal-MCP-Hub-sandboxed |
| cd Universal-MCP-Hub-sandboxed |
| cp example-mcp___.env .env |
| # fill in your keys |
| pip install -r requirements.txt |
| python main.py |
| ``` |
|
|
| Minimum required ENV vars (everything else is optional): |
|
|
| ```env |
| PYFUNDAMENTS_DEBUG="" |
| LOG_LEVEL="INFO" |
| LOG_TO_TMP="" |
| ENABLE_PUBLIC_LOGS="true" |
| HF_TOKEN="" |
| HUB_SPACE_URL="" |
| MCP_TRANSPORT="sse" |
| ``` |
|
|
| --- |
|
|
| ## Connect an MCP Client |
|
|
| ### Claude Desktop / any SSE-compatible client |
|
|
| ```json |
| { |
| "mcpServers": { |
| "universal-mcp-hub": { |
| "url": "https://YOUR_USERNAME-universal-mcp-hub.hf.space/sse" |
| } |
| } |
| } |
| ``` |
|
|
| ### Private Space (with HF token) |
|
|
| ```json |
| { |
| "mcpServers": { |
| "universal-mcp-hub": { |
| "url": "https://YOUR_USERNAME-universal-mcp-hub.hf.space/sse", |
| "headers": { |
| "Authorization": "Bearer hf_..." |
| } |
| } |
| } |
| } |
| ``` |
|
|
| --- |
|
|
| ## Desktop Client |
|
|
| A full PySide6 desktop client is included in `DESKTOP_CLIENT/hub.py` — ideal for private or non-public Spaces where you don't want to expose the SSE endpoint. |
|
|
| ```bash |
| pip install PySide6 httpx |
| # optional file handling: |
| pip install Pillow PyPDF2 pandas openpyxl |
| python DESKTOP_CLIENT/hub.py |
| ``` |
|
|
| **Features:** |
| - Multi-chat with persistent history (`~/.mcp_desktop.json`) |
| - Tool/Provider/Model selector loaded live from your Hub |
| - File attachments: images, PDF, CSV, Excel, ZIP, source code |
| - Connect tab with health check + auto-load |
| - Settings: HF Token + Hub URL saved locally, never sent anywhere except your own Hub |
| - Full request/response log with timestamps |
| - Runs on Windows, Linux, macOS |
|
|
| [→ Desktop Client docs](DESKTOP_CLIENT/README.md) |
|
|
| --- |
|
|
| ## Configuration (.pyfun) |
|
|
| `app/.pyfun` is the single source of truth for all app behavior. Three tiers — use what you need: |
|
|
| ``` |
| LAZY: [HUB] + one [LLM_PROVIDER.*] → works |
| NORMAL: + [SEARCH_PROVIDER.*] + [MODELS.*] → works better |
| PRODUCTIVE: + [TOOLS] + [HUB_LIMITS] + [DB_SYNC] → full power |
| ``` |
|
|
| Adding a new LLM provider requires two steps — `.pyfun` + one line in `providers.py`: |
|
|
| ```ini |
| # 1. app/.pyfun — add provider block |
| [LLM_PROVIDER.mistral] |
| active = "true" |
| base_url = "https://api.mistral.ai/v1" |
| env_key = "MISTRAL_API_KEY" |
| default_model = "mistral-large-latest" |
| models = "mistral-large-latest, mistral-small-latest, codestral-latest" |
| fallback_to = "" |
| [LLM_PROVIDER.mistral_END] |
| ``` |
|
|
| ```python |
| # 2. app/providers.py — uncomment the dummy + register it |
| _PROVIDER_CLASSES = { |
| ... |
| "mistral": MistralProvider, # ← uncomment to activate |
| } |
| ``` |
|
|
| `providers.py` ships with ready-to-use commented dummy classes for OpenAI, Mistral, and xAI/Grok — each with the matching `.pyfun` block right above it. Most OpenAI-compatible APIs need zero changes to the class itself, just a different `base_url` and `env_key`. Search providers (Brave, Tavily) follow the same pattern and are next on the roadmap. |
|
|
| Model limits, costs, and capabilities are also configured here — `get_model_info` reads directly from `.pyfun`: |
|
|
| ```ini |
| [MODEL.claude-sonnet-4-6] |
| provider = "anthropic" |
| context_tokens = "200000" |
| max_output_tokens = "16000" |
| requests_per_min = "50" |
| cost_input_per_1k = "0.003" |
| cost_output_per_1k = "0.015" |
| capabilities = "text, code, analysis, vision" |
| [MODEL.claude-sonnet-4-6_END] |
| ``` |
|
|
| --- |
|
|
| ## Dependencies |
|
|
| ``` |
| # PyFundaments Core (always required) |
| asyncpg — async PostgreSQL pool (Guardian/cloud DB) |
| python-dotenv — .env loading |
| passlib — PBKDF2 password hashing in user_handler.py |
| cryptography — encryption layer in fundaments/ |
| |
| # MCP Hub |
| fastmcp — MCP protocol + tool registration |
| httpx — async HTTP for all provider API calls |
| quart — async Flask (ASGI) — needed for SSE + hypercorn |
| hypercorn — ASGI server — long-lived SSE connections, HF Spaces native |
| requests — sync HTTP for tool workers |
| |
| # Optional (uncomment in requirements.txt as needed) |
| # aiofiles — async file ops (ML pipelines, file uploads) |
| # discord.py — Discord bot integration (app/discord_api.py, planned) |
| # PyNaCl — Discord signature verification |
| # psycopg2-binary — alternative PostgreSQL driver |
| ``` |
|
|
| The core stack is intentionally lean. `asyncpg` + `quart` + `hypercorn` + `fastmcp` + `httpx` covers the full MCP server. Everything else is opt-in. |
|
|
| --- |
|
|
| ## Security Design |
|
|
| - API keys live in HF Secrets / `.env` — never in `.pyfun`, never in code |
| - `list_active_tools` returns key **names** only — never values |
| - `db_query` is SELECT-only, enforced at application level (not just docs) |
| - `app/*` has zero import access to `fundaments/` internals |
| - Direct execution of `app/app.py` is blocked by design — prints a warning and uses a null-fundaments dict |
| - `fundaments/` is initialized conditionally — missing services degrade gracefully, they don't crash |
|
|
| > PyFundaments is not perfect. But it's more secure than most of what runs in production today. |
|
|
| [→ Full Security Policy](SECURITY.md) |
|
|
| --- |
|
|
| ## Foundation |
|
|
| This hub is built on [PyFundaments](PyFundaments.md) — a security-first Python boilerplate providing: |
|
|
| - `config_handler.py` — env loading with validation |
| - `postgresql.py` — async DB pool (Guardian-only) |
| - `encryption.py` — key-based encryption layer |
| - `access_control.py` — role/permission management |
| - `user_handler.py` — user lifecycle management |
| - `security.py` — unified security manager composing the above |
|
|
| None of these are accessible from `app/*`. They are injected as a validated dict by `main.py`. |
|
|
| [→ PyFundaments Function Overview](PyFundaments%20–%20Function%20Overview.md) |
| [→ Module Docs](docs/app/) |
|
|
| --- |
|
|
| ## History |
|
|
| [ShellMaster](https://github.com/VolkanSah/ChatGPT-ShellMaster) (2023, MIT) was the precursor — browser-accessible shell for ChatGPT with session memory via `/tmp/shellmaster_brain.log`, built before MCP was even a concept. Universal MCP Hub is its natural evolution. |
|
|
| --- |
|
|
| ## License |
|
|
| Dual-licensed: |
|
|
| - [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0) |
| - [Ethical Security Operations License v1.1 (ESOL)](ESOL) — mandatory, non-severable |
|
|
| By using this software you agree to all ethical constraints defined in ESOL v1.1. |
|
|
| --- |
|
|
| *Architecture, security decisions, and PyFundaments by Volkan Kücükbudak.* |
| *Built with Claude (Anthropic) as a typing assistant for docs & the occasional bug.* |
|
|
| > crafted with passion — just wanted to understand how it works, don't actually need it, have a CLI 😄 |
|
|
