--- name: architecture-paradigm-microkernel description: 'Minimal core system with plugin-based feature extensibility for platform development. Triggers: microkernel, plugin-architecture, extensibility, platform-design Use when: platforms/IDEs/marketplaces, core stability critical, plugin isolation needed DO NOT use when: selecting paradigms (use architecture-paradigms first), no extensibility needed.' category: architectural-pattern tags: - architecture - microkernel - plugin - extensibility - platform-design dependencies: [] tools: - plugin-loader - sandbox-executor - sdk-generator usage_patterns: - paradigm-implementation - platform-development - extensibility-design complexity: high estimated_tokens: 900 --- # The Microkernel (Plugin) Architecture Paradigm ## When To Use - Building extensible systems with plugin architectures - Products requiring customer-specific customizations ## When NOT To Use - Monolithic applications without plugin extensibility needs - Systems where all features are core and tightly coupled by design ## When to Employ This Paradigm - When building platforms, Integrated Development Environments (IDEs), data ingestion pipelines, or marketplaces where third parties need to extend core functionality. - When the core system requires extreme stability, while extensions and features must evolve and change rapidly. - When isolating optional dependencies and sandboxing untrusted code provided by plugins is critical. ## Adoption Steps 1. **Define Core Services**: Clearly delineate the minimal responsibilities of the microkernel, such as scheduling, component lifecycle management, core domain primitives, and messaging. 2. **Specify the Plugin Contract**: Design and document the formal contract for all plugins, including registration procedures, capability descriptors, lifecycle hooks (e.g., start, stop), and the permission model. 3. **Build the Extension Loader and Sandbox**: Implement the mechanisms for loading extensions, performing version compatibility checks, negotiating capabilities, and isolating plugins to prevent failures from cascading. 4. **Provide a Software Development Kit (SDK)**: To facilitate plugin development, provide an SDK with project templates, testing harnesses, and compatibility-checking tools. 5. **Govern the Release Process**: Maintain a clear compatibility matrix between core and plugin versions. Implement an automated regression test suite that validates core functionality against a variety of plugins. ## Key Deliverables - An Architecture Decision Record (ADR) describing the division of responsibilities between the core and plugins, along with the governance model for plugin development and certification. - Formal documentation for the security and permission model, detailing what capabilities are available to plugins. - An automated plugin validation pipeline that performs linting, runs tests, and executes the plugin within a sandbox environment. ## Risks & Mitigations - **Uncontrolled Plugin Proliferation**: - **Mitigation**: Without a curation process, the maintenance cost of supporting numerous plugins can become unsustainable. Enforce a formal certification process or a marketplace-style review for all third-party plugins. - **Version Skew Between Core and Plugins**: - **Mitigation**: Use semantic versioning (SemVer) rigorously for both the core and the plugins. Where necessary, provide abstraction layers or "shims" to maintain backward compatibility with older plugins. - **Core System Bloat**: - **Mitigation**: There is often pressure to add feature logic to the stable core. Aggressively resist this temptation. The core should remain minimal, with new features implemented as plugins whenever possible. ## Troubleshooting ### Common Issues **Command not found** Ensure all dependencies are installed and in PATH **Permission errors** Check file permissions and run with appropriate privileges **Unexpected behavior** Enable verbose logging with `--verbose` flag