using-the-mcp-server

Using the MCP Server

The html-to-markdown MCP server exposes the converter's conversion and metadata-extraction capabilities as MCP tools, so an MCP-compatible client (Claude Code, Claude Desktop) can convert HTML and pull structured metadata directly, with no CLI invocation or glue code.

How it runs in this plugin

The plugin auto-registers the server. Its command is the bundled launcher scripts/mcp-launch.sh, which execs html-to-markdown mcp. On first run the launcher resolves an html-to-markdown binary: it reuses one already on PATH or cached in the plugin's bin/, then tries npx/uvx, then Homebrew, then downloads a prebuilt from the tool's latest GitHub release. Override the channel with HTML_TO_MARKDOWN_LAUNCHER=auto|npx|uvx|brew|download.

The mcp subcommand ships in a recent release of the tool. If an older html-to-markdown is already on PATH, it may not expose mcp yet — upgrade the binary (brew upgrade, re-download, or rebuild) to pick it up.

To run it manually:

html-to-markdown mcp        # for Claude Code / Claude Desktop (stdio)

The tools

• convert_html — convert an HTML string to Markdown, Djot, or plain text. Takes html (the HTML string), an optional config object mirroring ConversionOptions, and an optional json flag. With json: true it returns the full ConversionResult (content, tables, metadata, document structure, inline images, warnings) instead of the bare converted text.
• extract_metadata — pull structured metadata (document info, Open Graph / Twitter / JSON-LD / Microdata, headers, links, images) from an HTML string. Takes only html.

Both tools accept an HTML string — the MCP server does not fetch URLs or read files (that is CLI-only). The exact argument schemas come from the running server; ask the client to list tools to see the live surface.

When to prefer MCP over the CLI or SDK

• Prefer MCP inside an agent session: the agent calls the converter directly as a tool, with no shell-out and no process management.
• Prefer the CLI for one-shot conversions and shell pipelines (… | jq).
• Prefer the SDK when embedding conversion in application code.