Sr Software Engineer

About The Role

Lexsi Labs is seeking a Sr Software Engineer to own the coding agent: an autonomous system that takes objectives, works directly on repositories within customer networks (often without internet), verifies changes before human review, and produces detailed records of actions taken.

You Will Work On:

• Building agent architecture for software work including retrieval, editing, builds, tests, static analysis, and version control.
• Safety verification to ensure changes are correct before deployment.
• Long-horizon execution across multi-file refactors with checkpointing and self-correction.
• Developing authorization models and rollback strategies for agent actions.
• Integrating with engineering estates, enterprise auth systems (Git, Jenkins, etc.), and observability tooling like OpenTelemetry.
• Crafting evaluation suites from real repository tasks to tune behavior.

We Are Looking For:

This is a developer tooling role as much as an AI research role. You need deep experience with IDE internals, LSPs, code intelligence (ASTs, static analysis), and build systems like Bazel or Maven.

Strong backend fundamentals in Python, APIs, containerization, databases, and on-premise/offline infrastructure are essential. We value substance over polish, execution over rhetoric, and expect you to own problems from architecture to production behavior.