Worked on the CopilotKit/CopilotKit repository to address a critical issue affecting Angular OnPush components, specifically ensuring that agent messages rendered correctly in the UI. Applied a targeted fix by emitting a new messages array when adding messages, which triggered Angular’s change detection and resolved a regression caused by identical array references. Enhanced reliability by introducing regression tests that covered both in-place mutation scenarios and OnPush descendant rendering, using TypeScript and Vitest for robust validation. Maintained code quality through cleanup efforts, including the removal of redundant comments, and focused on preserving referential stability to optimize frontend performance and UI accuracy.