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WebMCP Demo Store

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WebMCP demo store: same catalog via MCP tool calls vs DOM scraping. -79% bytes, -42% tokens.

Source code Website Documentation

Install

Add this to your client's MCP configuration (Claude Desktop: claude_desktop_config.json; Cursor: .cursor/mcp.json; VS Code and others use the same "mcpServers" shape).

Remote (streamable-http)
Claude Code 
claude mcp add --transport http webmcp-demo-store 'https://demowithmcp.converso.work/mcp'
JSON configuration (Claude Desktop, Cursor, VS Code) 
{
    "mcpServers": {
        "webmcp-demo-store": {
            "type": "http",
            "url": "https://demowithmcp.converso.work/mcp"
        }
    }
}

Documentation

From the project's README on GitHub, refreshed weekly. Links open on GitHub.

Contents
  1. WebMCP Demo Store — one-file server, two modes, one benchmark
  2. Run it
  3. Live demos
  4. Chrome-native WebMCP test (13 Oct 2026)
  5. Repo layout
  6. License

WebMCP Demo Store — one-file server, two modes, one benchmark

Same store, same tools, two delivery modes:

  • WebMCP mode — the page exposes its catalog through MCP tool calls (MCP-over-HTTP /mcp, plus Chrome-native document.modelContext), so an agent reads only what the task needs.
  • Plain mode — the same store as an ordinary website; the agent parses full HTML pages, as every agent must today.

Benchmark (150-product catalog, identical tasks): 79% less action bytes, 42% fewer input tokens, 8/8 tasks correct in both modes. DOM mode wins on small catalogs then collapses; WebMCP wins with age. Crossover report: report.html → WebMCP_Comparison_Report.pdf.

Run it

python3 server.py                    # plain mode      → http://localhost:9501
MCP=1 PORT=9502 python3 server.py    # WebMCP mode     → http://localhost:9502 + /mcp

stdlib-only (http.server, json, uuid, threading) — no pip install, no dependencies.

Live demos

Chrome-native WebMCP test (13 Oct 2026)

Chrome 154 + --enable-features=WebMCP exposes document.modelContext on HTTPS origins (about:blank excluded).

  • Registered the 5-tool store contract via the IMPERATIVE API (registerTool): search_products, add_to_cart, get_cart, checkout (server-backed; all fetches in-page).
  • Standard client flow verified: getTools() discovery → executeTool() calls → orders 1017/1018 placed, T2/T4/T8 picks correct (HP Pavilion 14, Razer DeathAdder, OnePlus 12R).
  • 154 build quirks found & worked around:
    1. executeTool(tool, args) requires args as a JSON string (object form throws "Failed to parse input arguments"); return values are JSON strings too — JSON.parse both sides.
    2. Tools can't be re-registered under the same name (InvalidStateError) — reload the page to reset.
    3. Flag/feature name: --enable-features=WebMCP works headless; docs' chrome://flags/#enable-webmcp-testing is the manual path. Note: API is document.modelContext (moved from navigator since July 2026 build).
  • Takeaway: the demo's tool contract is compatible with Chrome's native WebMCP, not just our JSON-RPC shim. When Chrome ships the client agent (Gemini-in-Chrome), the store is already agent-ready.

Repo layout

pathwhat
server.pythe whole thing: store + cart + orders + MCP transport (MCP=1) + static/report serving
catalog.json / catalog_10.json150-product / 10-product demo catalogs
compare.py, compare_llm.py, browser_llm.pybenchmark harnesses (DOM-mode agent, LLM-token accounting, browser-native flow)
make_report.pyregenerates the HTML/PDF reports from results.json / agg_150_vs_30.json
whitepaper.html, report*.html, *.pdf, chart_*.pngstrategy + evidence artifacts (launch deck included)
weekly_recap.pycounters + live-URL digest (used by the ops cron)

License

MIT.

Frequently asked questions

What is WebMCP Demo Store?

WebMCP demo store: same catalog via MCP tool calls vs DOM scraping. -79% bytes, -42% tokens.

How do I install WebMCP Demo Store?

It runs as a remote server. In Claude Code: claude mcp add --transport http webmcp-demo-store 'https://demowithmcp.converso.work/mcp'. For other clients, paste the JSON configuration from this page into their MCP settings.

Does WebMCP Demo Store need an API key?

Its registry entry lists no required key or secret. Some features may still need an account with the service it connects to.

Is WebMCP Demo Store open source?

Yes. Its code is on GitHub under the MIT license.

Who maintains WebMCP Demo Store?

It is published by kamatanuj. AI.tn lists it but does not maintain or endorse it.

From the official MCP Registry. Listing is not an endorsement: review a server's code and permissions before giving it access to your data.