Developed foundational metadata capabilities for the quantumlib/Cirq repository by introducing circuit tagging and metadata propagation features. Leveraging Python and object-oriented programming, refactored the AbstractCircuit class to support a unified tags attribute, enabling metadata to be attached and consistently propagated across circuit operations and serialization processes. This work involved careful API design and refactoring of core methods to ensure that tags are maintained throughout the circuit lifecycle, improving management, reproducibility, and serialization fidelity. The enhancements lay the groundwork for metadata-driven tooling and governance, supporting more robust circuit simulation workflows and enabling future extensibility in circuit management and reproducibility practices.