Client conformance checklist

This checklist is non-normative. The complete specification governs when wording differs.

Plugin loader

• Load a plugin from a directory and enforce the filesystem-resolved package boundary.
• Select locally supported manifest rules from $schema; do not retrieve a schema during loading.
• Validate the closed plugin.json schema and required $schema and name fields.
• Report and ignore unknown top-level fields.
• Ignore a non-object extensions field and unimplemented extension namespaces.
• Reject other fatal manifest violations before component discovery.

Discovery and isolation

• Discover supported component types only from their fixed locations.
• Treat missing component locations as valid absence.
• Isolate invalid component types, skills, and MCP entries at their specified boundaries.
• Ignore unsupported component types and support at least one of skills or MCP servers.

MCP support

• If MCP is implemented, support at least one of stdio and Streamable HTTP; support for both is recommended.
• Use each server entry's declared transport for the initial connection attempt.
• Validate the closed top-level document and each server entry independently.
• Resolve stdio commands as single executable tokens.
• Provide PLUGIN_ROOT and a dedicated persistent PLUGIN_DATA directory.
• Expand only the two defined placeholders and only in args, env values, and cwd.
• Enforce working-directory containment and remote URL/header requirements.
• Continue loading after an independent MCP server fails.

Versioning

• Require matching Agent Plugins versions in plugin.json and mcp.json.
• Never reassign a published canonical schema identifier to different contents.
• Allow plugins to continue targeting older versions according to locally supported compatibility policy.