mcp-multi-poc

PoC for serving multiple MCP servers from a single PyPI package, using subcommands for server selection and optional extras for on-demand dependencies. Stands in for the Couchbase MCP monorepo question (alpha = operational, beta = analytics, tabulate = the analytics SDK — chosen because it is outside fastmcp's transitive dependency tree; httpx and pyyaml are not, and silently defeat the extras guard).

What this PoC must answer

Local smoke test (before publishing anything)

cd mcp-registry-poc
uv venv && uv pip install -e .
mcp-multi-poc alpha          # starts alpha on stdio (Ctrl+C to exit)
mcp-multi-poc beta           # must FAIL with the friendly extras message
uv pip install -e ".[beta]"
mcp-multi-poc beta           # now starts
mcp-multi-poc                # bare command runs alpha (backward-compat check)
mcp-multi-poc-beta           # Option 1 script works locally once extra installed

uvx behavior (after publishing to PyPI):

uvx mcp-multi-poc alpha                  # base only
uvx "mcp-multi-poc[beta]" beta           # extras via uvx — key UX under test
uvx --from "mcp-multi-poc[beta]" mcp-multi-poc-beta   # Option 1 fallback form

Publish steps (manual, in order)

1. If mcp-multi-poc is taken on PyPI, pick another name and rename consistently (pyproject name, [project.scripts], both server.json identifiers).
2. Build and publish to real PyPI (registry validation fetches from pypi.org; TestPyPI will not work): uv build && uv publish.
3. Install mcp-publisher and log in: mcp-publisher login github (interactive) — must match the io.github.<username> namespace.
4. Publish the entries: mcp-publisher publish server.alpha.json, ... server.beta.json, and ... server.beta-script.json — the last one is expected to fail validation; record the exact error (if the CLI expects the file at ./server.json, copy each into place first).
5. Verify via the registry API: curl "https://registry.modelcontextprotocol.io/v0/servers?search=mcp-multi-poc"
6. Configure both servers in a client from the registry metadata and call echo (alpha) and make_table (beta).
7. Record results per question above, then deprecate/delete the PoC entries.

MCP client config for manual testing (pre-registry)

{
  "mcpServers": {
    "poc-alpha": { "command": "uvx", "args": ["mcp-multi-poc", "alpha"] },
    "poc-beta":  { "command": "uvx", "args": ["mcp-multi-poc[beta]", "beta"] }
  }
}