publicmcp

Build and self-host a PUBLICMCP business identity MCP server.

PUBLICMCP is an open standard for public-facing business identity MCP servers: structured, read-only business data that any AI agent or MCP client can query. This repository holds the specification (SPEC.md) and a reference Python package.

PUBLICMCP is self-hosted only. Each business runs its own server. There is no central registry, hosted service, or verification program.

What's new in 0.4.1 (2026-10-25)

• Self-hosted only. The central registry, directory, verification badges, hosted service and public library are retired. publicmcp.org is no longer used. The standard's home is sltcreative.com/publicmcp.
• Spec 0.4.1 is an editorial revision of v0.4: the registry section is removed, the spec URL now points to SPEC.md on GitLab, and Appendix A covers self-hosting. Servers still declare publicmcp_version: "0.4".
• Package: the publicmcp router command and its registry tools are removed. init and serve are unchanged.

Quickstart

Requires Python 3.10+.

pip install publicmcp
publicmcp init          # create business.json
publicmcp serve         # start server on :8000

Point your MCP client at http://localhost:8000/mcp.

What the reference package does

publicmcp serve starts a FastMCP server that exposes your business.json as read-only MCP tools. Browsers that open /mcp (or any path other than /, /info and /.well-known/publicmcp.json) are redirected to the publicmcp_page set in business.json; AI agents get MCP.

Plus one prompt: sales_workflow, a tool-chaining guide for sales agents.

Not yet in the package: get_markets, get_products, search_site_content, get_page_content, list_site_pages, check_project_fit and /.well-known/agents.json. The package also still declares an earlier publicmcp_version, names itself publicmcp-server (spec 3.1 expects {business-slug}-publicmcp), sends no server instructions (3.2), and its get_portfolio filters and response shape differ from spec 5.1. For full v0.4 compliance, add these yourself or build your own server against SPEC.md.

CLI reference

publicmcp init [--output business.json] [--force]
    Create a starter business.json template.

publicmcp serve [--business business.json] [--host 0.0.0.0] [--port 8000] [--domain your.domain.com]
    Start the server. --domain sets the URL in the discovery endpoint. Always pass it in
    production: the default comes from the business.json website field, without www.

Endpoints

Discovery

Servers should publish /.well-known/publicmcp.json and /.well-known/agents.json (spec section 11). Sites on hosted platforms (Duda, Shopify, Wix, Squarespace) that can't serve files can use a DNS TXT record instead:

_agents.yourdomain.com.  TXT  "v=agents0.1; type=publicmcp; endpoint=https://mcp.yourdomain.com/mcp; version=0.4"

Production deployment

Run behind a reverse proxy with TLS on a dedicated subdomain. With Caddy:

mcp.yourdomain.com {
    reverse_proxy 127.0.0.1:8000
}

publicmcp serve --business business.json --host 127.0.0.1 --port 8000 --domain mcp.yourdomain.com

Add CORS headers (Access-Control-Allow-Origin: *) at the proxy so browser-based agents can read your endpoints.

Example deployment: Salt Creative self-hosts its server at https://mcp.sltcreative.com/mcp.

Links

• Spec: SPEC.md
• PyPI: pypi.org/project/publicmcp
• Maintainer: Salt Creative

License

Apache 2.0. See LICENSE.