Add MCP (Model Context Protocol) experiment

[Jameswlepage]

Summary

Adds MCP server integration for WordPress, enabling AI assistants like Claude Desktop, Cursor, and VS Code to interact with WordPress capabilities via the Model Context Protocol.

Addresses #37

Features

• MCP Server Management: Configure multiple MCP servers with customizable routes and transport options
• Tool Discovery: Automatically expose WordPress abilities as MCP tools
• Admin Dashboard: Full React-based admin UI for server configuration and monitoring
• Client Configuration: Auto-generate config snippets for Claude Desktop, Cursor, Windsurf, VS Code, and JetBrains IDEs
• Connection Testing: Built-in endpoint testing to verify server connectivity

Related

See also #63 (Abilities Explorer) - the MCP admin UI and Abilities Explorer share similar concepts around displaying and managing WordPress abilities. Future work could explore sharing components or patterns between them.

Changes

• includes/Experiments/MCP/ - PHP backend (Manager, Admin_Page, REST controller)
• src/admin/mcp-server/ - React admin UI with DataViews
• docs/experiments/mcp.md - Documentation

Test plan

• Enable the MCP experiment in AI settings
• Navigate to the MCP admin page
• Verify server status shows as "Running"
• Enable/disable specific tools via the tools table
• Copy a client configuration and test in Claude Desktop or Cursor
• Use the "Test connection" feature to verify endpoint

[codecov]

Codecov Report

❌ Patch coverage is 0.90498% with 657 lines in your changes missing coverage. Please review.
✅ Project coverage is 38.28%. Comparing base (1351969) to head (0bb4efe).
⚠️ Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
includes/Experiments/MCP/Manager.php	0.00%	463 Missing ⚠️
includes/Experiments/MCP/REST/MCP_Controller.php	0.00%	126 Missing ⚠️
includes/Experiments/MCP/Admin_Page.php	0.00%	54 Missing ⚠️
includes/Experiments/MCP/MCP.php	26.31%	14 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff               @@
##             develop     #152       +/-   ##
==============================================
- Coverage      50.80%   38.28%   -12.53%     
- Complexity       375      513      +138     
==============================================
  Files             27       31        +4     
  Lines           1978     2641      +663     
==============================================
+ Hits            1005     1011        +6     
- Misses           973     1630      +657     

Flag	Coverage Δ
unit	38.28% <0.90%> (-12.53%)	⬇️

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[Copilot]

Pull request overview

This PR adds a comprehensive MCP (Model Context Protocol) experiment that enables AI assistants like Claude Desktop, Cursor, and VS Code to interact with WordPress capabilities via the Model Context Protocol. The implementation includes a full-stack solution with PHP backend management, React-based admin UI, REST API endpoints, and extensive configuration options.

Key Changes:

• Full MCP server management system with multi-server support and configurable routes
• React-based admin dashboard with DataViews for managing exposed abilities and server configuration
• REST API controller for server CRUD operations, tool management, and connection testing
• Auto-generated client configuration templates for popular MCP clients

Reviewed changes

Copilot reviewed 36 out of 36 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
webpack.config.js	Adds entry point for admin/mcp-server bundle
src/admin/mcp-server/types.ts	TypeScript type definitions for MCP UI state
src/admin/mcp-server/index.tsx	Main React app component with state management
src/admin/mcp-server/components/*.tsx	React components for UI features (tools table, config generator, status cards)
src/admin/mcp-server/style.scss	Component styles and layout definitions
src/admin/hooks/usePersistedView.ts	Hook for persisting DataViews state
src/admin/components/icons/*.tsx	Provider icon components (AI, Anthropic, Google, etc.)
src/admin/components/provider-icons.tsx	Icon lookup utility
src/admin/_dataviews.scss	DataViews styling overrides
src/admin/_common.scss	Common admin page styles
includes/Experiments/MCP/Manager.php	Core PHP manager for MCP configuration and server lifecycle
includes/Experiments/MCP/REST/MCP_Controller.php	REST API endpoints for MCP operations
includes/Experiments/MCP/Admin_Page.php	Admin page registration and asset enqueuing
includes/Experiments/MCP/MCP.php	Experiment entry point and registration
includes/Experiment_Loader.php	Registers MCP experiment in loader
docs/experiments/mcp.md	Comprehensive documentation for the MCP experiment

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[jeffpaul]

@Jameswlepage can you add tests here like was done in https://github.com/WordPress/ai/pull/147/changes#diff-0cf348eda48cae411ad9d44a2e5b449603a971f2313b0a849893ff4cf8280c46?

[jeffpaul]

• Reminder for us to add a screenshot gif and entry in the readme.txt for this feature before merging/releasing.

[raftaar1191]

I think this functionality belongs in the MCP Adapter plugin itself rather than the AI Experiments plugin.

Since it is MCP-specific behavior, keeping it within the adapter would maintain clearer separation of concerns and ensure the adapter remains the canonical place for MCP-related logic.

[webmyc]

Multi-server support with auto-exposing abilities as tools is exactly the right architecture. Good to see this taking shape.

I registered 100+ tools as WordPress Abilities in Respira (page builder editing over MCP) and ran into a few things that may be relevant here:

Schema serialization gotcha. When input_schema has "properties": {} (tools with no required params), PHP's json_encode serializes it as [] instead of {}, which breaks JSON Schema validation on the client side. I had to walk every schema and replace empty arrays under properties keys with new stdClass() before registration. Worth handling in the adapter layer so every plugin doesn't have to solve this independently.

Annotation hints matter for tool selection. With 100+ tools exposed, AI clients use readOnlyHint and destructiveHint to decide which tools to call speculatively vs. which to gate behind confirmation. I set these per-tool at registration time via ability_annotations. If the admin UI lets users enable/disable individual tools, surfacing these hints in the UI would help site owners understand what they're toggling.

Multisite context switching. On multisite, abilities registered on the main site need a way to execute against a different blog. I wrap every execute_callback in a switch_to_blog() / restore_current_blog() block based on user meta. The MCP Adapter doesn't seem to account for this — might be worth a note in the docs or a hook for plugins to inject site context.

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The client config generation is something I'd benefit from directly - I built my own config endpoint and the format alignment would be useful. Happy to share my registration and adapter integration code if any of it is useful reference for this PR.