docs(publishing): answer the agent's question on the MCP page, and give the site root real content

[jswir]

Why

Someone asking an AI assistant "how do I let a coding agent query my warehouse safely" does not currently reach these pages, and the two pages most likely to be cited are the two least able to answer.

What changed

The site root served a redirect shim. src/index.html used layouts/redirect.html, which emits <title>Page Redirection</title>, ~15 words of body, and a one-second meta-refresh. Deployment is GitHub Pages so a real 301 is not available from this repo — but the root does not need to redirect at all. It now serves a short landing page: what Malloy is, what Publisher is, how to serve a model over MCP, and links into the docs. The /documentation link stays first so humans still get there in one click.

The MCP page opened with a feature description — "Connect AI assistants to your Malloy semantic models using the Model Context Protocol". It now opens with the question people arrive with, and answers it: the agent queries the semantic model, so it works from the sources, joins and measures you defined and cannot invent a table or write arbitrary SQL against production.

The quick start now shows claude mcp add alongside the JSON config, and a short section covers moving the same model from local DuckDB to a warehouse. Stdio bridging and reload semantics are unchanged; they now follow the job rather than preceding it.

Second commit: the page was out of date with Publisher. Three fixes:

• Start command. --server_root <dir> with no config starts a server that reports serving with no packages. Both the MCP page and the new landing page now lead with the bundled examples (npx @malloy-publisher/server@latest) and the scaffolder for your own data, then show a check that packages actually loaded.
• Tool reference. It used the pre-rename malloy_* names, and described get_context parameters it no longer takes. It now lists the eight tools Publisher registers, including list_packages, get_status and search_database_schema, which the page never mentioned.
• Security note. It said Publisher binds 0.0.0.0, so port 4040 is open. The MCP port binds 127.0.0.1 by default (server.ts:259). The REST port binds 0.0.0.0, and REST reaches the same data, so the warning now names that port.

TOC: MCP for AI Agents moves from sixth to second in Publishing, directly after Publish Your Models.

Incidental fix: layouts/redirect.html interpolated {{ site.baseurl }} twice in all four of its URLs. Harmless only because every npm script passes --baseurl ''. That layout is still used by src/slack.html and documentation/samples.malloynb.

Verification

npm run build-prod, which is what CI runs.

• The build reports 1539 pre-existing errors on this checkout. A clean build of origin/main reports the same 1539 — these changes add none.
• All nine links from the new root page resolve.
• The root renders with a real title and 442 words, previously 15.
• mcp_agents.html and samples.html both still render correctly.

I have not tried to fix the pre-existing build errors; they look unrelated (undefined airports in visualization notebooks) and belong in their own PR.