InstaHost WordPress MCP

An installable WordPress plugin that adds secure content-management abilities to the official WordPress MCP Adapter.

Architecture

This plugin does not implement a competing MCP transport. It registers WordPress Abilities and creates a focused MCP Adapter server at:

https://example.com/wp-json/mcp/instahost-wordpress

MCP Adapter owns the HTTP transport, MCP sessions, schema conversion, error handling, and ability execution. InstaHost WordPress MCP supplies the content abilities and their WordPress capability checks.

For desktop MCP clients, use Automattic MCP WordPress Remote as the local stdio-to-WordPress bridge. It supports OAuth 2.1, JWT, Application Passwords, proxy configuration, and MCP Adapter session forwarding.

Abilities

• instahost-wordpress/get-site-info
• instahost-wordpress/list-posts
• instahost-wordpress/get-post
• instahost-wordpress/search
• instahost-wordpress/create-post (optional)
• instahost-wordpress/update-post (optional)
• instahost-wordpress/delete-post (optional)

Write abilities are disabled by default. Enable them under Settings > InstaHost MCP.

Managed automatic enrollment

Managed deployments can make the MCP connection available automatically after plugin activation. Provision these values through wp-config.php without committing them:

define( 'INSTAHOST_WORDPRESS_MCP_REGISTRY_URL', 'https://registry.example.com/v1/enroll' );
define( 'INSTAHOST_WORDPRESS_MCP_ENROLLMENT_TOKEN', '<single-use-token>' );

The plugin schedules an HTTPS enrollment, creates a restricted dedicated MCP identity, and sends the registry a revocable route-scoped bearer token. It never sends administrator credentials, content, cookies, or database data. Public installs with no deployment-time token make no outbound request.

The receiving registry must verify the site through the advertised MCP endpoint, protect against SSRF/DNS rebinding, encrypt the connection token, and keep writes disabled unless the WordPress administrator enables them. See docs/managed-enrollment.md for the complete contract.

Requirements

• WordPress 6.9 or newer
• PHP 8.0 or newer
• MCP Adapter 0.6.1 or newer
• HTTPS for remote access

Install

1. Download mcp-adapter.zip from the MCP Adapter releases, then install and activate it.
2. Upload and activate InstaHost WordPress MCP.
3. Open Settings > InstaHost MCP.
4. Copy the generated @automattic/mcp-wordpress-remote@0.4.0 configuration and replace the credential placeholders, or configure OAuth/JWT.

Example remote configuration

{
  "mcpServers": {
    "instahost-wordpress": {
      "command": "npx",
      "args": ["-y", "@automattic/mcp-wordpress-remote@0.4.0"],
      "env": {
        "WP_API_URL": "https://example.com/wp-json/mcp/instahost-wordpress",
        "WP_API_USERNAME": "your-wordpress-username",
        "WP_API_PASSWORD": "your-application-password",
        "OAUTH_ENABLED": "false"
      }
    }
  }
}

OAuth is preferred where the WordPress site provides compatible authorization metadata. Application Passwords must be used only over HTTPS.

Security model

• MCP Adapter transport permission requires an authenticated user with edit_posts.
• Every ability independently checks the relevant WordPress capabilities.
• Publish, private, trash, and delete operations have explicit capability gates.
• Non-forced deletion is rejected when WordPress recoverable trash is disabled.
• The tested remote bridge is pinned to @automattic/mcp-wordpress-remote@0.4.0.
• Non-published list results are limited to the current author unless the caller can edit others' content.
• Revisions, autosaves, and inaccessible password-protected content are not returned.
• Managed enrollment credentials authenticate only on the dedicated MCP route.
• Invalid ihmcp_ credentials fail closed without intercepting unrelated JWT/OAuth bearer tokens.
• Public installs make no phone-home request unless a registry URL and one-time enrollment token are explicitly provisioned.
• Mutation input is sanitized through WordPress APIs.
• Uninstall removes only this plugin's setting; it never deletes WordPress content.

Build and test

php tests/smoke.php
INSTAHOST_TEST_TRASH_DAYS=0 php tests/smoke.php
php tests/enrollment.php
php tests/enrollment-unconfigured.php
php scripts/check-version.php
sh scripts/build.sh

The installable artifact is written to dist/.

License

GPL-2.0-or-later