Senior Software Engineer, Agentic Development

ST6 is a company that builds portfolio management and analytics software for institutional investors and is committed to becoming AI-native by the end of 2025. They are seeking a Senior Software Engineer to join their agentic development team, where the role involves delivering features, operating multi-agent workflows, and ensuring quality in production systems.

Responsibilities:

• Deliver features and modernizations across our stack using agentic development end-to-end
• Build and operate multi-agent workflows where distinct roles run in parallel and in coordination
• Work in brownfield environments with the same discipline as greenfield builds
• Validate agent output and know when to intervene — grounded in how well requirements were set upfront
• Pair with existing engineers to transfer agentic working habits through real production work
• Contribute consistently to sprint delivery and take ownership of quality over time

Requirements:

• 5–9 years of professional software engineering experience
• Strong fluency in Java or Python on AWS, or C# on Azure
• Production ownership history: you've shipped non-trivial systems and been accountable when things went wrong
• At least one significant out-of-depth experience — a stack switch, a domain change, or a greenfield build in unfamiliar territory
• 6+ months of serious, production-grade agentic tool use (Claude Code, Cursor, or equivalent) — production work only, not pilots or experiments
• Demonstrated ability to build product with AI, not just use AI within existing workflows
• Concrete understanding of when to let an agent run versus when to intervene, grounded in how well requirements were established before the work started
• Experience reviewing and validating work you did not write, including agent-generated output
• Familiarity with building multi-agent frameworks where distinct roles operate concurrently