DOC-3476: Add Context7 MCP setup instructions to llms.txt

Add AI-Assisted Development with MCP section to llms.txt with
Context7 MCP setup instructions for Cursor and Claude Code.

URL rewriting to index.md endpoints is handled by a separate
post-build pipeline step rather than hardcoding in source files.

Author: kemister85

modules/ROOT/attachments/llms.txt

@@ -117,6 +117,33 @@ TinyMCE AI (`tinymceai` plugin) is the current AI writing assistant for TinyMCE.
 - [Upgrading TinyMCE](https://www.tiny.cloud/docs/tinymce/latest/upgrading/): Upgrade guide
 - [Migration from 7.x](https://www.tiny.cloud/docs/tinymce/latest/migration-from-7x/): Migrate from TinyMCE 7
 
+## AI-Assisted Development with MCP
+
+For up-to-date TinyMCE documentation directly in AI coding tools, set up the Context7 MCP server. TinyMCE docs are indexed at [context7.com/tinymce/tinymce-docs](https://context7.com/tinymce/tinymce-docs).
+
+### Cursor
+
+Add to `.cursor/mcp.json`:
+
+```json
+{
+  "mcpServers": {
+    "context7": {
+      "command": "npx",
+      "args": ["-y", "@upstash/context7-mcp"]
+    }
+  }
+}
+```
+
+### Claude Code
+
+```bash
+claude mcp add context7 -- npx -y @upstash/context7-mcp
+```
+
+Add "use context7" to any prompt for live TinyMCE documentation lookups.
+
 ## Complete Documentation
 
 For a complete list of all 411 documentation pages, see [llms-full.txt](https://www.tiny.cloud/docs/llms-full.txt).