Create OpenCode plugins using the opencode-ai/plugin SDK. Use when user wants to build a plugin, extend OpenCode, intercept tool execution, add custom tools, react to events, create a hook, block commands, add custom auth, or add automation to OpenCode. Also use for 'opencode plugin', 'custom tool', 'tool hook', 'plugin hook', 'logging for all tool calls', 'restrict what commands the AI can run', 'lifecycle hooks', 'middleware', 'tool.execute.before', 'tool.execute.after', 'auth hook', 'chat.params', 'intercept bash commands', 'block file writes', 'add audit logging', 'custom model provider auth', 'inject context before LLM call', 'fire-and-forget background task', 'watch session events'.