Stoobly Agent is a monolithic Python application that acts as a man-in-the-middle HTTP(S) proxy for recording, mocking, replaying, and testing API interactions. Built on mitmproxy, it provides a comprehensive CLI (Click-based) for managing requests, scenarios, settings, and snapshots, as well as a scaffold system that generates full Docker Compose or local development workflows. The application supports four proxy modes (record, mock, test, develop) with configurable policies, rewrite rules, and lifecycle hooks that allow custom Python callbacks at various interception stages. It persists state to a local SQLite database via an ORM with migrations, and optionally integrates with a remote Stoobly cloud service for project and scenario management. The codebase exhibits a solid architecture with adapter patterns for converting between different HTTP representations (mitmproxy, Python requests, raw, ORM, Stoobly API), factory patterns for resource creation, and builder patterns for Docker Compose generation. However, it suffers from some technical drift (deprecated mitmproxy API usage, many lazy imports, global singletons) and the test suite includes flaky end-to-end tests that depend on external services. Overall, it is a well-crafted tool for API development and testing, with several reusable components, particularly the HTTP adapter system.