The .well-known/mcp.json manifest, explained
A `.well-known/mcp.json` manifest advertises that your domain offers an MCP server, so clients can discover your tools without being configured by hand.
Readable versus operable
llms.txt and structured data make you readable — an agent can describe your product. A manifest makes you operable — an agent can do something in it.
That is the jump from being mentioned in an answer to being the thing that completes the task.
Do you need one yet?
Only if you have an MCP server for it to point at. Manifest discovery conventions are still settling, and most real adoption today happens through explicit client configuration rather than domain discovery.
Publishing a manifest that points nowhere is worse than publishing none: it fails for anyone who tries it, which is a worse first impression than absence.
The order that works
Build the server. Get it working in a real client — Claude Desktop or Cursor, configured by hand. Fix what breaks when someone who is not you tries it. Then publish discovery metadata.
The manifest is the last step, not the first.
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