v0.6.0

MCP Adapter 0.6.0 improves protocol compatibility, resource metadata handling, session reliability, WP-CLI behavior, and coexistence with plugins that bundle their own copy of the adapter.

Before upgrading

• WordPress 6.9 or newer is now required. The standalone Abilities API plugin is no longer a supported installation path.
• Abilities with meta.public: true are now exposed through the default MCP server unless meta.mcp.public explicitly opts out. Existing permission callbacks and capability checks still apply.
• On multisite only, active Streamable HTTP sessions must reconnect once after upgrading because session storage moves from a network-wide key to separate per-site keys. Single-site installations are unaffected.
• The MIME validation helpers previously exposed by McpValidator have been removed. Integrations calling them directly should apply their own application-specific MIME validation.

MCP resources and metadata

• Preserve _meta on resource contents, embedded resources, content blocks, and prompt messages.
• Omit malformed _meta without discarding the payload it accompanies.
• Emit mimeType exactly as declared, including values with parameters such as text/html;profile=mcp-app.
• Correctly handle blob-only resource contents.
• Support resources/templates/list, returning an empty template list when no templates are available.
• Match resource URI schemes case-insensitively, so clients can read resources even when they normalize the scheme to lowercase.

These changes improve compatibility with MCP Apps and other clients that depend on resource metadata.

Reliability and compatibility

• Protect concurrent session mutations with bounded retries, reducing the risk of one request overwriting another session.
• Scope session storage by blog on WordPress multisite.
• Use Jetpack Autoloader so the newest available WP\MCP classes win when the standalone adapter and another plugin bundle different versions.
• Normalize empty arguments for schema-defining abilities, allowing valid zero-argument tool calls to execute correctly.

WP-CLI improvements

• Keep JSON-RPC stdout clean when wp mcp-adapter serve selects the default server.
• Use WP-CLI’s global --user argument instead of registering a conflicting local option.

Additional improvements

• Block direct execution of plugin PHP files.
• Clarify that the Abilities API is included in WordPress 6.9 and newer.
• Document the required ability category field and improve examples throughout the documentation.
• Expand automated compatibility, dependency, and Plugin Check coverage.

New contributors

Welcome to @johnbillion, @graham73may, @gziolo, @ustramooner, @matthewfarrugia, @robertocyrino, and @mathetos, who made their first contributions to MCP Adapter in this release.

Thank you to everyone who contributed code, documentation, testing, and reviews.

Full Changelog: v0.5.0...v0.6.0