Santander is seeking a senior Harness Engineer to design and deliver secure, production-grade harnesses enabling coding agents across the Knowledge Base Platform and related solutions. You will define architecture, integrate with Git workflows, CI/CD, observability, and cloud environments, while mentoring teams and establishing reusable patterns. The role requires 8+ years in software/AI engineering, strong leadership, Python and AWS experience, with a focus on secure SDLC and governance.